Category: Meeting Updates

Late Breaking Abstract – ESMO 2022: Apalutamide Plus Androgen Deprivation Therapy in Biochemically Relapsed Prostate Cancer

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SUMMARY: Prostate cancer is the most common cancer in American men with the exclusion of skin cancer, and 1 in 9 men will be diagnosed with prostate cancer during their lifetime. It is estimated that in the United States, about 268,490 new cases of prostate cancer will be diagnosed in 2022, and 34,500 men will die of the disease. The development and progression of prostate cancer is driven by androgens. Androgen Deprivation Therapy (ADT) or testosterone suppression has therefore been the cornerstone of treatment of advanced prostate cancer and is the first treatment intervention.

The major source of PSA (Prostate Specific Antigen) is the prostate gland, and the PSA levels are therefore undetectable within 6 weeks after Radical Prostatectomy. Similarly, following Radiation Therapy there is a gradual decline in PSA, before reaching a post treatment nadir. A detectable PSA level after Radical Prostatectomy, or a rising PSA level following Radiation Therapy, is considered PSA failure or biochemical recurrence. Approximately 35% of the patients with prostate cancer will experience PSA only relapse within 10 years of their primary treatment and a third of these patients will develop documented metastatic disease within 8 years following PSA only relapse. Rising PSA is therefore a sign of recurrent disease. Patient’s with biochemically relapsed prostate cancer following local therapy, and a short PSA doubling time, are at risk for distant metastases.

ERLEADA® (Apalutamide) is an orally administered Androgen Receptor (AR) inhibitor that binds directly to the ligand-binding domain of the AR. Apalutamide inhibits AR nuclear translocation, inhibits DNA binding, and impedes AR-mediated transcription. Apalutamide is presently approved for the treatment of patients with metastatic Castration Sensitive Prostate Cancer and non-metastatic Castration Resistant Prostate Cancer. ZYTIGA® (Abiraterone) is a selective, irreversible inhibitor of CYP 17A1 enzyme and decreases androgen biosynthesis in the testes, adrenal glands, and prostate-tumor tissue. Both Apalutamide and Abiraterone plus prednisone have been shown to prolong Overall Survival in the metastatic prostate cancer.

The purpose of this study was to evaluate if intensification of Androgen Deprivation Therapy (ADT) prolongs biochemical Progression Free Survival (PFS), in patients with biochemically relapsed prostate cancer. PRESTO is a randomized, open-label Phase III trial, in which 504 prostate cancer patients who had radical prostatectomy were included. Study patients had biochemical recurrence (PSA more than 0.05 ng/mL), a PSA doubling time of 9 months or less, and without distant metastases on conventional imaging (CT and Bone scan). Patients were randomized 1:1:1 to receive a finite 52-week treatment course with ADT alone (N=167), ADT plus Apalutamide (N=168), or ADT plus Apalutamide plus Abiraterone/Prednisone (N=169). Patients were stratified by PSA doubling time (less than 3 months versus 3-9 months) and patients were followed up following treatment completion with mostly lab assessment until PSA progression, at which point, treatment was per investigator discretion. Patient and disease characteristics at baseline were well balanced among the 3 study groups. The median age was 67 years and 84% of patients were white. The median PSA at baseline was 1.77 ng/mL. The PSA doubling time was less than 3 months for 26% of patients and between 3 and 9 months for 74% of patients. The median time between radical prostatectomy and baseline was 4.4 years. Overall, 85% of patients had prior radiation and 42% of patients had prior ADT. The Primary endpoint of the study was to compare biochemical Progression Free Survival (defined as increase in serum PSA of more than 0.2 ng/mL following treatment) in each experimental group with ADT alone. Secondary endpoints included safety, patient-reported Quality of Life (QOL), time to testosterone recovery (more than 50 ng/dL following treatment completion), Metastasis-Free Survival, and time to castration resistance.

The first planned interim analysis at a median follow-up of 21.5 months showed that both study groups significantly prolonged biochemical PFS compared to the control group. The median biochemical (PSA) PFS was 24.9 months with Apalutamide plus ADT versus 20.3 months with ADT alone (HR=0.52; P=0.00047). The median biochemical PFS was 26.0 months with ADT plus Apalutamide plus Abiraterone/Prednisone versus 20.0 months with ADT alone (HR=0.48; P=0.00008). A preplanned subgroup analysis based on stratification by PSA doubling time showed a consistent benefit in both study groups, compared to the control group, regardless of the length of PSA doubling time. The median time to testosterone recovery following treatment completion was 3.9 months with ADT alone, 3.8 months with Apalutamide plus ADT and 4.7 months with ADT plus Apalutamide plus Abiraterone/Prednisone. There was an increase in the incidence of adverse events with the addition of Abiraterone.

It was concluded that intensifying Androgen Receptor blockade with Apalutamide plus Androgen Deprivation Therapy prolongs biochemical PFS with a manageable safety profile and without impacting time to testosterone recovery, following a finite duration of treatment. The authors added that intensification of Androgen Receptor blockade should be considered in high-risk biochemically relapsed prostate cancer.

LBA63 – PRESTO: A phase III, open-label study of androgen annihilation in patients (pts) with high-risk biochemically relapsed prostate cancer (AFT-19). Aggarwal R, Heller G, Hillman D, et al. Annals of Oncology (2022) 33 (suppl_7): S808-S869. 10.1016/annonc/annonc1089

Late Breaking Abstract – ASCO 2022: Landmark Five Year Overall Survival Rates for OPDIVO® and YERVOY® Combination in NSCLC

RR

SUMMARY: The American Cancer Society estimates that for 2022, about 236,740 new cases of lung cancer will be diagnosed and 135,360 patients will die of the disease. Lung cancer is the leading cause of cancer-related mortality in the United States. Non-Small Cell Lung Cancer (NSCLC) accounts for approximately 85% of all lung cancers. Of the three main subtypes of NSCLC, 30% are Squamous Cell Carcinomas (SCC), 40% are Adenocarcinomas and 10% are Large Cell Carcinomas. With changes in the cigarette composition and decline in tobacco consumption over the past several decades, Adenocarcinoma now is the most frequent histologic subtype of lung cancer.

Immune checkpoints are cell surface inhibitory proteins/receptors that are expressed on activated T cells. They harness the immune system and prevent uncontrolled immune reactions by switching off the immune system T cells. Immune checkpoint proteins/receptors include CTLA-4 (Cytotoxic T-Lymphocyte Antigen 4, also known as CD152) and PD-1(Programmed cell Death 1). Checkpoint inhibitors unleash the T cells resulting in T cell proliferation, activation, and a therapeutic response. OPDIVO® (Nivolumab) is a fully human, immunoglobulin G4 monoclonal antibody that binds to the PD-1 receptor and blocks its interaction with PD-L1 and PD-L2, thereby undoing PD-1 pathway-mediated inhibition of the immune response and unleashing the T cells. YERVOY® is a fully human immunoglobulin G1 monoclonal antibody that blocks Immune checkpoint protein/receptor CTLA-4.

CheckMate-227 is an open-label, multi-part, global, Phase III trial in which OPDIVO® based regimens were compared with Platinum-doublet chemotherapy in patients with first line advanced NSCLC, across non-squamous and squamous tumor histologies. This study consisted of Part 1a/Part 1b and Part 2. In Part 2 of this trial, OPDIVO® plus chemotherapy was compared with chemotherapy alone, regardless of PD-L1 expression. Part 2 did not meet its Primary endpoint for Overall Survival for OPDIVO® plus chemotherapy versus chemotherapy alone, in patients with non-squamous NSCLC, and is published elsewhere.

Part 1a: Patients received OPDIVO® 3 mg/kg IV every 2 weeks plus YERVOY® 1 mg/kg IV every 6 weeks (N=396), OPDIVO® monotherapy 240 mg IV every 2 weeks (N=396) or chemotherapy alone given every 3 weeks for up to four cycles (N=397), in patients whose tumors had PD-L1 expression of 1% or more.
Part 1b: Patients received OPDIVO® plus YERVOY® (N=187), OPDIVO® 360 mg IV every 3 weeks plus chemotherapy IV every 3 weeks for up to four cycles (N=177), or chemotherapy alone IV every 3 weeks for up to four cycles (N=186), in patients whose tumors did not express PD-L1 (less than 1%)

Patients were stratified by histology, and treatment was administered until disease progression, unacceptable toxicity, or administered for 2 years for immunotherapy. It should be noted that when this trial was launched, chemotherapy along with immunotherapy or immunotherapy alone was not approved for the front-line treatment of NSCLC. Therefore, dual immunotherapy combination was not compared with current standards of care such as chemotherapy plus immunotherapy.

There were two independent Primary endpoints in Part 1 for OPDIVO® plus YERVOY® versus chemotherapy: Overall survival (OS) in patients whose tumors express PD-L1 (assessed in patients enrolled in Part 1a) and Progression Free Survival (PFS) in patients with TMB of 10 mut/Mb or more, across the PD-L1 spectrum (assessed in patients enrolled across Part 1a and Part 1b). Other assessments included Objective Response Rate (ORR), Duration of Response (DOR), and treatment-free interval. Treatment-free interval was measured in patients who discontinued study therapy and was defined as the time from last study dose to start of subsequent systemic therapy.

The Overall Survival (OS) data was previously reported at a minimum follow up of 29 months, and the median OS was of 17.1 months for the OPDIVO® plus YERVOY® group, compared to 14.9 months in the chemotherapy group (HR=0.79; P=0.007), with a 2-year OS rate of 40.0% and 32.8%, respectively. The researchers here in presented data after a minimum follow up of 61.3 months (5 years).

Patients whose tumors had PD-L1 expression of 1% or more continued to have sustained long term OS benefit with OPDIVO® plus YERVOY® when compared to chemotherapy (HR=0.77), and the 5-year OS rates were 24% with OPDIVO® plus YERVOY® compared to 14% with chemotherapy alone.

Patients with a PD-L1 expression of less than 1% also demonstrated continued long term OS benefit with OPDIVO® plus YERVOY® when compared to chemotherapy (HR = 0.65), and the 5-year OS rates were 19% for OPDIVO® plus YERVOY&reg compared to 7% for chemotherapy alone.

Among patients who survived for 5 years, median PFS was 59.1 months for PD-L1–positive patients and 60.7 months for PD-L1–negative patients who received OPDIVO® plus YERVOY®, compared to 9.5 months and 24.9 months respectively, for those who received chemotherapy.

Among those who responded to treatment, more patients who received OPDIVO® plus YERVOY® remained in response at five years, compared to chemotherapy, in both PD-L1 expression of 1% or more group (28% versus 3%) and PD-L1 expression of less than 1% group (21% versus 0%), respectively.

Among patients treated with OPDIVO® plus YERVOY® who were alive at five years, approximately two-thirds of patients did not receive any subsequent therapy for more than three years after stopping treatment, regardless of PD-L1 expression.

It was concluded that in this longest reported follow up of a Phase III trial of first line, chemotherapy free, combination immunotherapy, in metastatic Non Small cell Lung Cancer, a combination of OPDIVO® plus YERVOY® continued to provide long term durable clinical benefit and increased 5-year survivorship, when compared to chemotherapy, in previously untreated patients with metastatic NSCLC, regardless of PD-L1 expression.

Five-year survival outcomes with nivolumab (NIVO) plus ipilimumab (IPI) versus chemotherapy (chemo) as first-line (1L) treatment for metastatic non–small cell lung cancer (NSCLC): Results from CheckMate 227. Brahmer JR, Lee J-S, Ciuleanu T-E, et al. J Clin Oncol. 2022;40(suppl 17):LBA9025. doi:10.1200/JCO.2022.40.17_suppl.LBA9025

Late Breaking Abstract – ASCO 2022: Docetaxel as Radiosensitizer Improves Overall Survival in Cisplatin-Ineligible Head and Neck cancer

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SUMMARY: The American Cancer Society estimates that in the US for 2022, about 54,000 new cases of oral cavity or oropharyngeal cancer will be diagnosed and about 11,230 patients will die of the disease. Patients with squamous cell carcinoma of the head and neck, frequently present with locoregionally advanced disease. For patients in this setting, chemoradiotherapy is an effective non-surgical approach as primary treatment. Alternatively, chemoradiotherapy can be delivered as adjuvant therapy after a curative resection.

Cisplatin-based concurrent chemoradiation is generally accepted as the standard, definitive non-surgical and post-operative approach in selected patients with locoregionally advanced squamous cell carcinoma of the head and neck. This treatment can however be associated with substantial morbidity and lifelong toxicities. Cetuximab is an immunoglobulin G1 chimeric monoclonal antibody against Epidermal Growth Factor Receptor (EGFR), and the only approved targeted agent in locoregionally advanced squamous cell carcinoma of the head and neck. Cetuximab plus Radiotherapy significantly improved Overall Survival at 5 years, when compared with radiotherapy alone, in patients with locoregionally advanced squamous cell carcinoma of the head and neck (Lancet Oncol. 2010). Cetuximab plus Radiotherapy is therefore an important treatment option in this patient group. However, financial barriers make Cetuximab as a Cisplatin substitute, inaccessible to patients, in low and middle-income countries.

Docetaxel is a semisynthetic taxane that affects polymerized tubulin to promote microtubule formation and inhibit its disassembly. Docetaxel has been shown to have significant antitumor activity as a single agent in head and neck cancer, when given in the neoadjuvant setting. Docetaxel is also a potent radiosensitizer. The researchers evaluated Docetaxel as a radiosensitizer in this clinical trial.

The authors in this open-label, randomized, Phase III study enrolled 356 Cisplatin-ineligible patients with locally advanced head and neck squamous cell carcinoma, planned for treatment with radical or adjuvant chemoradiation. The patients were randomly assigned 1:1 to receive Radiation alone (N=176) or Radiation with concurrent Docetaxel 15 mg/m2 IV weekly for a maximum of 7 cycles (N=180). Both treatment groups were well balanced. The median age was 62 yrs, approximately 45% of patients had a ECOG Performance Status of 2, and reasons for Cisplatin ineligibility included low creatinine clearance (26%), and hearing loss (43%). Approximately 33% of patients had oral cavity cancer and about two-thirds of patients had Stage IVA disease. The FACT-G, and Head and Neck questionnaires were completed by patients at baseline, 6 months, 12 months and at 24 months. FACT-G (Functional Assessment of Cancer Therapy-G) is a 27-item questionnaire designed to measure four domains of Health-Related Quality of Life (HRQOL) in cancer patients, which includes physical, social, emotional, and functional well-being. The Primary endpoint was Disease Free Survival (DFS), and key Secondary endpoints included Overall Survival (OS), adverse events and Quality of Life.

It was noted that the 2-year DFS was 30.3% with Radiation alone versus 42% with Docetaxel plus Radiation Therapy (HR=0.67; P=0.002). Docetaxel plus Radiation Therapy also significantly improved Overall Survival. The median Overall Survival was 15.3 months with Radiation Therapy alone, versus 25.5 months in the Docetaxel plus Radiation Therapy group (P=0.035). The 2 -year Overall Survival was also significantly higher in the Docetaxel plus Radiation Therapy group and was 41.7% with Radiation Therapy alone, versus 50.8% in the Docetaxel plus Radiation Therapy group (HR=0.74; P=0.035). These survival outcomes were observed across all preplanned subgroups.

Grade 3 or above adverse events were seen in 58% of patients receiving Radiation Therapy alone and in 81.6% of patients receiving Docetaxel plus Radiation Therapy. The addition of Docetaxel to Radiation Therapy resulted in a higher incidence of Grade 3 and above mucositis (49.7% versus 22.2%; P<0.001), odynophagia (52.5% versus 33.5%; P<0.001) and dysphagia (49.7% versus 33%; P<0.002). The addition of Docetaxel however did not lead to a worsening of Quality of Life, including Trial Outcome Index and FACT-G scores at 6 months.

The authors concluded that the addition of Docetaxel to Radiation Therapy improved Disease Free Survival and Overall Survival, in Cisplatin-ineligible locally advanced head and neck squamous cell carcinoma, and provides an evidence based, financially more viable treatment option, for this patient group.

Results of phase 3 randomized trial for use of docetaxel as a radiosensitizer in patients with head and neck cancer unsuitable for cisplatin-based chemoradiation. Patil VM, Noronha V, Menon NS, et al. DOI: 10.1200/JCO.2022.40.17_suppl.LBA6003 Journal of Clinical Oncology 40, no. 17_suppl (June 10, 2022) LBA6003.

Late Breaking Abstract – ASCO 2022: Improved Distant Metastasis-Free Survival with Adjuvant KEYTRUDA® in High Risk Stage II Melanoma

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SUMMARY: The American Cancer Society’s estimates that for 2022, about 99,780 new cases of melanoma of the skin will be diagnosed in the United States and 7,650 people are expected to die of the disease. The rates of melanoma have been rising rapidly over the past few decades, but this has varied by age. Surgical resection with a curative intent is the standard of care for patients with early stage melanoma, with a 5-year survival rate of 98% for Stage I disease and 90% for Stage II disease. The current standard of care for patients following resection of high-risk Stage II disease is observation, even though patients with Stage IIB and IIC disease presenting with high-risk features (depth of invasion, T-category, ulceration) have 5 and 10 year melanoma-specific survival similar to that of patients with Stage IIIA and IIIB disease.

KEYTRUDA® (Pembrolizumab) is a fully humanized, Immunoglobulin G4, anti-PD-1, monoclonal antibody, that binds to the PD-1 receptor and blocks its interaction with ligands PD-L1 and PD-L2. By doing so, it unleashes the tumor-specific effector T cells, and is thereby able to undo PD-1 pathway-mediated inhibition of the immune response. The FDA in 2019, approved KEYTRUDA® for the adjuvant treatment of patients with melanoma, with involvement of lymph node(s), following complete resection (Stage III). The present study was conducted to evaluate the role of adjuvant immunotherapy in patients with high risk Stage II melanoma.

KEYNOTE-716 is a randomized, double-blind, Phase III trial, in which 976 patients aged 12 years or older, with completely resected cutaneous Stage IIB or IIC melanoma, and no lymph node involvement, were randomly assigned 1:1 to receive KEYTRUDA® 200 mg IV (2 mg/kg for pediatric patients) or placebo, every 3 weeks for 17 cycles (up to 1 year). Patients were stratified by T category 3b, 4a, 4b (adults) and with a separate stratum for pediatric patients. Approximately 65% had Stage IIB disease and 35% had Stage IIC disease. There was no prespecified analysis for PD-L1 or BRAF status in this study, as there was inconsistent and small amounts of tissue available for testing. This was the first part (Part 1) of this double-blind study. The Primary endpoint was Relapse Free Survival (RFS) per investigator assessment, and Safety. The second part (Part 2) of this study was open-label design, and adults and pediatric patients were eligible to receive up to 35 additional cycles of treatment, only if they had recurrence after receiving the placebo or completed 17 cycles of KEYTRUDA®. Patients in the KEYTRUDA® group who experienced disease recurrence within 6 months of completing the treatment were excluded from Part 2 of the study. Secondary end points included Distant Metastasis Free Survival (DMFS), Overall Survival (OS) and Quality of Life.

At median follow up of 14.4 months, adjuvant KEYTRUDA® significantly prolonged RFS compared to placebo (HR=0.65; P=0.00658), in patients with resected Stage IIB or IIC melanoma. At the time of this analysis, 11.1% of patients on KEYTRUDA® had a recurrence, compared to 16.8% of those receiving placebo. The 12-month RFS rate was 90.5% for KEYTRUDA® versus 83.1% for placebo.

The researchers herein presented new data from the analysis of Distant Metastasis-Free Survival (DMFS) and Recurrence Free Survival (RFS), with a longer median follow up of 26.9 months. Adjuvant KEYTRUDA® significantly improved DMFS when compared to placebo (HR=0.64; P=0.0029), representing a 36% reduction in the risk of recurrence. The 24-month DMFS rate was 88.1% versus 82.2%, respectively. Grade 3 or more Adverse Events occurred in 28.4% of patients in the KEYTRUDA® group, versus 20% in the placebo group. Hypothyroidism was the most common immune mediated Adverse Event with KEYTRUDA®, compared to placebo (17.2% versus 3.7%).

The authors concluded that adjuvant KEYTRUDA® for resected Stage IIB and IIC melanoma, significantly improved Distant Metastasis-Free Survival, with continued reduction in the risk of recurrence, and a favorable benefit-risk profile. KEYNOTE-716 is the first randomized Phase III trial of an anti-PD-1 therapy in resected Stage II melanoma, and these findings represent an important milestone for this patient group.

Distant metastasis-free survival with pembrolizumab versus placebo as adjuvant therapy in stage IIB or IIC melanoma: The phase 3 KEYNOTE-716 study. Long GV, Luke JJ, Khattak M, et al. DOI: 10.1200/JCO.2022.40.17_suppl.LBA9500 Journal of Clinical Oncology 40, no. 17_suppl (June 10, 2022) LBA9500-LBA9500.

Late Breaking Abstract – ASCO 2022: RUBRACA® Monotherapy as Maintenance Treatment in Newly Diagnosed Ovarian Cancer

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SUMMARY: It is estimated that in the United States, approximately 19,880 women will be diagnosed with ovarian cancer in 2022 and 12,810 women will die of the disease. Ovarian cancer ranks fifth in cancer deaths among women, and accounts for more deaths than any other cancer of the female reproductive system. Approximately 75% of the ovarian cancer patients are diagnosed with advanced disease. Approximately 85% of all ovarian cancers are epithelial in origin, and approximately 70% of all epithelial ovarian cancers are High-Grade Serous adenocarcinomas. Patients with newly diagnosed advanced ovarian cancer are often treated with platinum based chemotherapy following primary surgical cytoreduction. Approximately 70% of these patients will relapse within the subsequent 3 years and are incurable, with a 5 year Overall Survival rate of about 20-30%.

DNA damage is a common occurrence in daily life by UV light, ionizing radiation, replication errors, chemical agents, etc. This can result in single and double strand breaks in the DNA structure which must be repaired for cell survival. The two vital pathways for DNA repair in a normal cell are BRCA1/BRCA2 and PARP. BRCA1 and BRCA2 are tumor suppressor genes and they recognize and repair double strand DNA breaks via Homologous Recombination (HR) pathway. Homologous Recombination is a DNA repair pathway utilized by cells to accurately repair DNA double-stranded breaks during the S and G2 phases of the cell cycle, and thereby maintain genomic integrity.

Homologous Recombination Deficiency (HRD) is noted following mutation of genes involved in HR repair pathway. At least 15 genes are involved in the Homologous Recombination Repair (HRR) pathway including BRCA1 and BRCA2 genes. Mutations in BRCA1 and BRCA2 account for about 20-25% of hereditary breast cancers 15% of ovarian cancers, in addition to other cancers such as colon and prostate. BRCA mutations can either be inherited (Germline) and present in all individual cells or can be acquired and occur exclusively in the tumor cells (Somatic).

The PARP (Poly ADP Ribose Polymerase) family of enzymes includes PARP1 and PARP2, and is a related enzymatic pathway that repairs single strand breaks in DNA. In a BRCA mutant, the cancer cell relies solely on PARP pathway for DNA repair to survive. PARP inhibitors traps PARP onto DNA at sites of single-strand breaks, thereby preventing their repair and generate double-strand breaks. These breaks cannot be repaired accurately in tumors harboring defects in Homologous Recombination Repair pathway genes, such as BRCA1 or BRCA2 mutations, and this leads to cumulative DNA damage and tumor cell death.

RUBRACA® is an oral, small molecule PARP inhibitor, developed for treatment of ovarian cancer associated with Homologous Recombination DNA repair deficiency (HRD). With regards to ovarian cancer, RUBRACA® is presently approved by the FDA for the maintenance treatment of patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer, who are in a Complete or Partial Response to platinum-based chemotherapy.

ATHENA is an international, multicenter, randomized, double-blind, placebo-controlled, Phase III trial, which evaluated first-line maintenance treatment for patients with newly diagnosed advanced ovarian cancer. ATHENA was designed to evaluate RUBRACA® first-line maintenance treatment in a broad group of patients, including those without BRCA1 or BRCA2 (BRCA) mutations or other evidence of Homologous Recombination Deficiency (HRD), or high-risk clinical characteristics such as residual disease. ATHENA study has two separate and fully independently powered comparisons evaluating RUBRACA® monotherapy (ATHENA–MONO) and RUBRACA® plus Nivolumab (ATHENA–COMBO), as maintenance treatment in this patient population. The authors herein reported the efficacy and safety results from the ATHENA–MONO comparison of RUBRACA® maintenance treatment versus placebo.

In the ATHENA-MONO trial, patients with Stage III-IV high-grade ovarian cancer undergoing surgical cytoreduction (R0/complete resection permitted) and responding to 4-8 cycles of first-line platinum-doublet chemotherapy, were randomly assigned 4:1 to receive RUBRACA® 600 mg orally twice daily (N=427) or placebo. Treatment was continued for 24 months or until disease progression or unacceptable toxicity. Patients were stratified by HRD test status, residual disease after chemotherapy, and timing of surgery (primary surgery versus interval debulking). The median age was 61 years, majority of the patients (78%) did not have a BRCA mutation. Patients were stratified by HRD classification (BRCA wild-type/LOH (Loss of Heterozygosity) high-16% or more, BRCA wild-type/LOH low-less than 16%, and BRCA wild-type/LOH indeterminate). The Primary end point of investigator-assessed Progression Free Survival (PFS) was assessed in a step-down procedure, first in the HRD population (BRCA-mutant or BRCA wild-type/LOH high tumor), and then in the Intent-To-Treat (ITT) population. Secondary end points included Overall Survival (OS), investigator-assessed Objective Response Rate (ORR) in patients with measurable disease at baseline and Duration of Response (DOR) for patients with investigator-assessed confirmed radiographic Complete Response (CR) or Partial Response (PR). The median duration of follow was 26 months.

The median PFS in the HRD population was 28.7 months with RUBRACA® maintenance group compared to 11.3 months with placebo (HR=0.47; P=0.0004). In the Intent to Treat (ITT) population, the median PFS was 20.2 months in the RUBRACA® group versus 9.2 months in the placebo group (HR=0.52; P<0.0001). At 24 months, 45% of RUBRACA®-treated patients in the ITT population were progression-free compared with 25.4% with placebo. In the HRD negative population, the median PFS was 12.1 months in the RUBRACA® group versus 9.1 months in the placebo group (HR=0.65). Exploratory subgroup analyses of PFS in the ITT population showed that there was greater clinical benefit with RUBRACA® compared to placebo among all subgroups, including BRCA-mutant, BRCA wild-type/LOH high, and BRCA wild-type/LOH low (HRD-negative).

Among RUBRACA®-treated patients with measurable disease at baseline, the ORR, was 58.8% in the HRD population and 48.8% in the ITT population. Among the placebo-treated patients, the ORR was 20% in the HRD population and 9.1% in the ITT population. The median Duration of Response in the HRD and ITT populations for RUBRACA®-treated responders versus the placebo-treated responders respectively, was 16.7 months versus 5.5 months and 22.1 months versus 5.5 months. The Overall Survival results were immature at the time of the data cutoff. The most common Grade 3 or more adverse events in the RUBRACA® group were anemia (29%) and neutropenia 15%).

The authors concluded that in the ATHENA-MONO trial, RUBRACA® monotherapy is an effective first-line maintenance option that provides clinical benefit to a broad population of patients with newly diagnosed ovarian cancer, regardless of BRCA mutation and HRD status.

A Randomized, Phase III Trial to Evaluate Rucaparib Monotherapy as Maintenance Treatment in Patients With Newly Diagnosed Ovarian Cancer (ATHENA–MONO/GOG-3020/ENGOT-ov45). Monk BJ, Parkinson C, Lim MC, et al. DOI: 10.1200/JCO.2022.40.17_suppl.LBA5500 Journal of Clinical Oncology 40, no. 17_suppl (June 10, 2022) LBA5500-LBA5500. Published online June 08, 2022.

Late Breaking Abstract – ASCO 2022: Nimotuzumab Significantly Improves Overall Survival in K-Ras Wild-Type Advanced Pancreatic Cancer

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SUMMARY: The American Cancer Society estimates that in 2022, about 62,210 people will be diagnosed with pancreatic cancer and 49,830 people will die of the disease. Pancreatic cancer is the fourth most common cause of cancer-related deaths in the United States and Western Europe. Unfortunately, unlike other malignancies, very little progress has been made and outcome for patients with advanced pancreatic cancer has been dismal, with a 5-year survival rate for metastatic pancreatic cancer of approximately 10%. Pancreatic cancer has surpassed breast cancer as the third leading cause of cancer death in the United States and is on track to surpass colorectal cancer, to move to the second leading cause of cancer related deaths in the United States.

Majority of patients with pancreatic cancer (80% of cases) are diagnosed at an advanced stage, and are not amenable to curative surgical resection, at the time of diagnosis. The current treatment regimens for advanced disease have proved ineffective, conferring a median Overall Survival (OS) of 6-8 months. In patients with pancreatic ductal adenocarcinoma, the main driver is the KRAS oncogene, which is mutationally activated in over 90% of cases, and is more common in older (50 years or more) and female patients. However approximately 8-12% of patients with pancreatic ductal adenocarcinoma do not harbor KRAS mutations.

Nimotuzumab is a humanized anti-EGFR monoclonal antibody, that binds to EGFR (Epidermal Growth Factor Receptor) and disrupts the interaction of the EGFR with its ligand, specifically blocking the EGFR signaling pathway, and mediating Antibody-Dependent Cellular Cytotoxicity (ADCC) and other immune effects, and inducing EGFR endocytosis and degradation. Nimotuzumab as a single agent showed activity in high grade brain tumors, and resulted in high rates of antitumor response in patients with locally advanced squamous cell carcinomas of the head and neck, when combined with radiation therapy. Nimotuzumab is approved in different countries for the treatment of Squamous Cell Carcinoma of Head and Neck (SCCHN), Glioma and Nasopharyngeal carcinoma.

NOTABLE is a prospective, double-blind, Phase III trial in which the efficacy and safety of Nimotuzumab in combination with Gemcitabine was compared with Gemcitabine alone, in patients with KRAS wild-type, locally advanced or metastatic pancreatic cancer. In this study, 92 patients with locally advanced or metastatic pancreatic cancer were randomly assigned to receive either Nimotuzumab 400 mg IV every week followed by Gemcitabine 1000 mg/m2 IV on days 1, 8, and 15 of every 28-day cycle or placebo plus Gemcitabine. Treatment was continued until disease progression or unacceptable toxicity. The treatment groups were well balanced. The median age was 56 years and approximately 56% had prior surgical management or treatment of biliary duct obstruction. The Primary endpoint was Overall Survival (OS), and Secondary endpoints included Progression Free Survival (PFS), Objective Response Rate (ORR), and Safety. The researchers envisioned that patients who did not need surgical management or treatment of biliary duct obstruction, typically would have better liver function without jaundice, and therefore would better tolerate chemotherapy. A subgroup analyses was therefore conducted based on whether the patients needed surgical management or treatment of bile duct obstructions prior to receiving chemotherapy.

The median Overall Survival was significantly longer in the Nimotuzumab/Gemcitabine group compared to those who received placebo plus Gemcitabine (10.9 months versus 8.5 months; HR=0.50; P=0.025). The one-year survival rate was 43.6% in the Nimotuzumab/Gemcitabine group versus 26.8% in the placebo-Gemcitabine group and the 3-year survival rate was 13.9% and 2.7%, respectively. The median Progression Free Survival was 4.2 months in the Nimotuzumab/Gemcitabine group compared to 3.6 months in the placebo plus Gemcitabine group (HR=0.56; P=0.013).

Among those patients who did not need surgical management or treatment of biliary duct obstruction, subgroup analyses showed significantly more survival benefit in patients without treatment of biliary obstruction (11.9 months versus. 8.5 months; HR=0.54; P=0.037) and among those with no surgical history (15.8 months versus 6.0 months; HR=0.40). Patients without treatment of biliary obstruction also had a significantly longer PFS (5.5 months versus 3.4 months; P=0.008) respectively. There was no statistical difference in the Objective Response Rates between the two treatment groups (P>0.05). Grade 3 adverse events in the Nimotuzumab/Gemcitabine group were neutropenia (11%), leukopenia (9%) and thrombocytopenia (7%). No Grade 4 adverse events were noted.

It was concluded that Nimotuzumab in combination with Gemcitabine, significantly increased Overall Survival and Progression Free Survival, in patients with K-Ras wild-type locally advanced or metastatic pancreatic cancer. This benefit was even more in patients who did not need surgical management or treatment of biliary duct obstruction.

Nimotuzumab combined with gemcitabine versus gemcitabine in K-RAS wild-type locally advanced or metastatic pancreatic cancer: A prospective, randomized-controlled, double-blinded, multicenter, and phase III clinical trial. Qin S, Bai Y, Wang Z, et al. J Clin Oncol. 2022;40(suppl 17):LBA4011. doi:10.1200/JCO.2022.40.17_suppl.LBA4011.

Late Breaking Abstract – ASCO 2022: FOLFOXIRI Plus Bevacizumab in Unresectable Colorectal Cancer with Liver Metastases

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SUMMARY: ColoRectal Cancer (CRC) is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society estimates that approximately 151,030 new cases of CRC will be diagnosed in the United States in 2022 and about 52,580 patients are expected to die of the disease. The lifetime risk of developing CRC is about 1 in 23.

Approximately 15-25% of the patients with CRC present with metastatic disease at the time of diagnosis (synchronous metastases) and 50-60% of the patients with CRC will develop metastatic disease during the course of their illness. First line treatment of metastatic CRC include Oxaliplatin or Irinotecan, in combination with a Fluoropyrimidine and Leucovorin (FOLFOX or FOLFIRI), along with a VEGF targeting agent such as Bevacizumab. Patients with stage IV colorectal cancer are now routinely analyzed for extended RAS and BRAF mutations. KRAS mutations are predictive of resistance to EGFR targeted therapy. Approximately 8-15% of all metastatic CRC tumors present with BRAF V600E mutations and BRAF V600E is recognized as a marker of poor prognosis in this patient group. These patients tend to have aggressive disease and do not respond as well to standard treatment intervention. Approximately 20% of the BRAF-mutated population in the metastatic setting has MSI-High tumors, but MSI-High status does not confer protection to this patient group. Colorectal cancer patients with unresectable liver-only metastases at the time of initial presentation may potentially be cured, after downsizing of metastases by neoadjuvant systemic therapy. However, the optimal neoadjuvant induction regimen has not been defined.

CAIRO5 is a prospective, randomized, multicentre, Phase III trial, conducted to investigate the optimal systemic induction therapy for patients with initially unresectable, liver-only colorectal cancer metastases. In this study, 294 patients were randomized to receive either FOLFOX or FOLFIRI plus Bevacizumab (N=148), or FOLFOXIRI plus Bevacizumab (N=146) for up to 12 cycles. Bevacizumab was given at a dose of 5 mg/kg IV. FOLFOX/FOLFIRI regimen consisted of either Oxaliplatin 85 mg/m2 IV or Irinotecan 180 mg/m2 IV, given along with Leucovorin 400 mg/m2 IV over 120 minutes, 5-Flourouracil (5-FU) 400 mg/m2 IV, followed by 5-FU 2400 mg/m2 given as an IV infusion over 46 hours. FOLFOXIRI regimen consisted of Oxaliplatin 85 mg/m2 IV, Irinotecan 165 mg/m2 IV, given along with Leucovorin 400 mg/m2 IV over 120 minutes, followed by 5-FU 3200 mg/m2 given as an IV infusion over 46 hours. Treatment was given every 2 weeks for a maximum of 12 cycles, followed by 5-FU, Leucovorin and Bevacizumab maintenance until disease progression. Enrolled patients had metastatic CRC with previously untreated liver-only metastases, (un)resectability status was prospectively assessed by a central panel consisting of radiologists and liver surgeons, according to predefined criteria, and patients were assessed for resectability every 2 months. Eligible patients had right-sided primary tumor and/or RAS or BRAF V600E mutated tumor. Both treatment groups were well balanced. The median age was 63 years, 41% had right-sided primary tumor, 86% of tumors had RAS mutation, 7% had BRAF V600E mutation, 5% had prior adjuvant chemotherapy, the median number of colorectal liver metastases was 12, and 87% had potentially resectable colorectal metastases. Patients were stratified by potentially resectable versus permanently unresectable colorectal liver metastases, BRAFV600E mutation, sidedness and choice of Irinotecan versus Oxaliplatin. The Primary endpoint was Progression Free Survival (PFS). Secondary endpoints included R0/1 resection, Overall Survival (OS), Overall Response Rate (ORR), toxicity, pathologic response and postoperative morbidity.

At a median follow up of 41 months, the median PFS was 9.0 months with doublet regimen FOLFOX/FOLFIRI plus Bevacizumab versus 10.6 months with the triplet regimen of FOLFOXIRI plus Bevacizumab. (HR=0.74; P=0.02). The ORR was 32% in the FOLFOX/FOLFIRI plus Bevacizumab group versus 52.1% in the FOLFOXIRI plus Bevacizumab group (P<0.001), R0/1 resection/ ablation rates were 37.4% versus 51.4% (P=0.02), and postoperative complications occurred in 38.2% versus 51.2% (P=0.14), respectively. Overall Survival data was immature at the time of data cutoff. Grade 3 or more adverse events, including neutropenia and diarrhea, were more common in the FOLFOXIRI plus Bevacizumab group.

It was concluded that in patients with initially unresectable colorectal cancer liver metastasis and right-sided and/or RAS or BRAF-mutated primary tumor, the triplet regimen of FOLFOXIRI plus Bevacizumab resulted in superior Progression Free Survival, a higher Objective Response Rate, and a greater chance for R0/R1 hepatic metastasectomy with or without ablation, compared to doublet chemotherapy with FOLFOX or FOLFIRI plus Bevacizumab. This benefit with the triplet regimen was achieved at the cost of increased toxicity, suggesting that careful patient selection should be made for the triplet regimen.

FOLFOXIRI + bevacizumab versus FOLFOX/FOLFIRI + bevacizumab in patients with initially unresectable colorectal liver metastases (CRLM) and right-sided and/or RAS/BRAFV600E-mutated primary tumor: Phase III CAIRO5 study of the Dutch Colorectal Cancer Group. Punt CJA, Bond MJG, Bolhuis K, et al. J Clin Oncol. 2022;40(suppl 17):LBA3506.

Late Breaking Abstract – ASCO 2022: RVd Plus Autologous Stem Cell Transplantation and REVLIMID® Maintenance Improves PFS in Multiple Myeloma

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SUMMARY: Multiple Myeloma is a clonal disorder of plasma cells in the bone marrow and the American Cancer Society estimates that in the United States, 34,470 new cases will be diagnosed in 2022 and 12,640 patients will die of the disease. Multiple Myeloma is a disease of the elderly, with a median age at diagnosis of 69 years and characterized by intrinsic clonal heterogeneity. Almost all patients eventually will relapse, and patients with a high-risk cytogenetic profile, extramedullary disease or refractory disease have the worst outcomes. The introduction of Proteasome Inhibitors, immunomodulatory agents and CD 38 targeted therapies has resulted in higher Response Rates, as well as longer Progression Free Survival (PFS) and Overall Survival (OS), with the median survival for patients with myeloma approaching 10 years or more. Nonetheless, Multiple Myeloma (MM) in 2022 remains an incurable disease.

In patients with newly diagnosed Myeloma who are eligible for transplant, the optimal use of triplet/quadruplet induction regimens, Autologous Stem Cell Transplantation (ASCT), and REVLIMID® (Lenalidomide)-based maintenance, continues to evolve. In the IFM 2009 French trial, REVLIMID® maintenance treatment was admininstered for one year and after a median follow-up of 89.8 months, the median Progression Free Survival (PFS) was 47.2 months with RVd plus ASCT and 35 months with RVd alone, but there was no Overall Survival (OS) benefit.

DETERMINATION ((Delayed vs Early Transplant with Revlimid Maintenance and Antimyeloma Triple Therapy) trial is a randomized Phase III trial, conducted to determine whether Autologous Stem Cell Transplantation (ASCT) enhances the efficacy of first line triplet induction therapy or whether it should be kept in reserve for select group of patients. In this study, 722 patients with symptomatic newly diagnosed Myeloma were enrolled. All patients received 3 cycles of RVd followed by stem cell mobilization (for possible ASCT if disease progressed). Patients were then randomly assigned to receive 5 additional cycles of RVd (RVd-alone arm, N=357) or Melphalan at 200 mg/m2, followed by ASCT and 2 additional cycles of RVd (RVd+ASCT arm, N=365). Each RVd cycle consisted of REVLIMID® 25 mg orally on days 1-14, VELCADE® (Bortezomib) 1.3 mg/m2 IV or SC on days 1, 4, 8, 11, and Dexamethasone given orally on days 1, 2, 4, 5, 8, 9, 11, 12, given as 21 day cycles. Dexamethasone was dosed at 20 mg/day for first 3 cycles and 10 mg/day for remaining cycles. Both treatment groups then received REVLIMID® maintenance at 10-15 mg orally daily, until disease progression or drug related toxicities. Both treatment groups were well balanced. The median age of enrolled patients was 56 years, approximately 14% of patients had ISS Stage III Multiple Myeloma and 18% had high-risk cytogenetics such as t(4;14), t(14;16), del17p. Approximately 19% of trial participants were African American, which is the highest representation of this subset of patients in any Phase III Myeloma trial. The Primary endpoint was Progression Free Survival (PFS). Secondary end points included Response Rates, Duration of Response (DOR), time to progression, Overall Survival (OS), Quality of Life, and Safety.

At a median follow up of 76 months, the median PFS was 46.2 months in the RVd alone group versus 67.6 months in the RVd plus ASCT group (HR=1.53; P<0.0001). The estimated 5-year PFS rates were 41.5% and 55.6% respectively. The 5 year Overall Survival was similar and not statistically different and was 79.2% and 80.7% respectively. The authors attributed the lack of Overall Survival in the RVd plus ASCT group to the availability of many highly effective treatment options now available after first-line therapy including salvage ASCT, next-generation immunomodulatory drugs, Proteasome Inhibitors, and monoclonal antibodies.

When evaluated by cytogenetic risk, for the standard risk group, the median PFS was 82.3 months in the RVd plus ASCT group versus 53.2 months in the RVd alone group, whereas for patients with high risk cytogenetics, the median PFS was 55.5 versus 17.1 months, respectively. Further, patients with t(4;14) derived more PFS benefit from RVd plus ASCT than those with del(17p). The PFS benefit with RVd plus ASCT was inferior among the African American enrollees and individuals with a Body Mass Index greater than 25 kg/m2.

Even though the Response Rates and quality of responses were similar between the two treatment groups, the Duration of Response was longer in the RVd plus ASCT group at 56.4 months, compared to 39.9 months in the RVd alone group.

More patients in the RVd plus ASCT group achieved MRD (Minimal Residual Disease) negativity compared to RVD alone (54.4% versus 39.8%), despite similar Complete Response Rates in both treatment groups. These MRD negative patients had favorable 5-year PFS, regardless of their treatment assignment. However, RVd plus ASCT improved PFS by 67% among the MRD positive patients.

Grade 3 or greater treatment-related adverse effects including mucositis, fatigue, and infections were less common without ASCT than with, at 78% versus 94% respectively. Secondary malignancies occurred in 10% of the RVd-alone group and 11% of the RVd plus ASCT group. Following RVd plus ASCT, 10 patients developed Myelodysplastic syndrome and/or Acute Myeloid Leukemia, compared with none in the RVd-alone group, and this was statistically significant (P=0.002).

The authors concluded that a combination of REVLIMID®, VELCADE® and Dexamethasone (RVd) plus ASCT as initial therapy followed by REVLIMID® maintenance until progression, demonstrated a significant improvement in PFS compared to RVd alone, followed by REVLIMID® maintenance, in patients with newly diagnosed Multiple Myeloma. There was no Overall Survival advantage observed to date. The researchers added that given the lack of benefit in OS and potential toxicities associated with ASCT, these data provide support for personalized treatment approaches, and helps patients make informed decision to delay transplant. Additionally, the significantly longer PFS for both treatment groups in the DETERMINATION study compared to the IFM 2009 (preplanned comparison), suggests that there is a clear benefit to continuous REVLIMID® maintenance until disease progression.

Lenalidomide, bortezomib, and dexamethasone (RVd) ± autologous stem cell transplantation (ASCT) and R maintenance to progression for newly diagnosed multiple myeloma (NDMM): The phase 3 DETERMINATION trial. Richardson PG, Jacobus SJ, Weller E, et al. J Clin Oncol. 2022;40(suppl 17):LBA4. doi:10.1200/JCO.2022.40.17_suppl.LBA4

Late Breaking Abstract – ASCO 2022: ENHERTU® for HER2-Low Advanced Breast Cancer

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SUMMARY: Breast cancer is the most common cancer among women in the US and about 1 in 8 women (12%) will develop invasive breast cancer during their lifetime. Approximately 290,560 new cases of breast cancer will be diagnosed in 2022 and about 43,780 individuals will die of the disease, largely due to metastatic recurrence.

It is estimated that approximately 60% of metastatic breast cancers categorized as HER2-negative express low levels of HER2, defined as a score of 1+ on ImmunoHistoChemical (IHC) analysis or as an IHC score of 2+ and negative results on In Situ Hybridization (ISH). These HER2-low breast cancer tumors are treated as HER2-negative, as currently available HER2-directed therapies have resulted in poor outcomes. These patients have limited targeted treatment options and are often treated with single agent palliative chemotherapy following progression on first line chemotherapy.

ENHERTU® (Trastuzumab Deruxtecan) is an Antibody-Drug Conjugate (ADC) composed of a humanized monoclonal antibody specifically targeting HER2, with the amino acid sequence similar to Trastuzumab, a cleavable tetrapeptide-based linker, and a potent cytotoxic Topoisomerase I inhibitor as the cytotoxic drug (payload). ENHERTU® has a favorable pharmacokinetic profile and the tetrapeptide-based linker is stable in the plasma and is selectively cleaved by cathepsins that are up-regulated in tumor cells. Unlike KADCYLA® (ado-Trastuzumab emtansine), ENHERTU® has a higher drug-to-antibody ratio (8 versus 4), released payload easily crosses the cell membrane with resulting potent cytotoxic effect on neighboring tumor cells regardless of target expression, and the released cytotoxic agent (payload) has a short half-life , thus minimizing systemic exposure. The potential activity of ENHERTU® in HER2-low breast cancer tumors is driven by the bystander antitumor effect, offered by the optimized ADC technology. Previously published Phase I and II trials have shown that ENHERTU® in heavily pretreated patients with HER2-low metastatic breast cancer resulted in an Overall Response Rate of 37%, and median Progression Free Survival ranging from 6.3 to 11.1 months.

DESTINY-Breast04 is a multicenter, randomized, open-label, Phase III trial, conducted to evaluate the efficacy and safety of ENHERTU® as compared with the physician’s choice of chemotherapy, in patients with HER2-low metastatic breast cancer. In this study, patients were randomly assigned in a 2:1 ratio to receive ENHERTU® 5.4 mg/kg IV every 3 weeks (N=373) or the physician’s choice of Capecitabine, Eribulin, Gemcitabine, Paclitaxel, or Nab-paclitaxel (N=184). Low expression of HER2 was defined as a score of 1+ on ImmunoHistoChemical (IHC) analysis or as an IHC score of 2+ and negative results on In Situ Hybridization (ISH). Randomization was stratified according to HER2-low status (IHC 1+ versus IHC 2+ and ISH-negative), the number of previous lines of chemotherapy for metastatic disease (one versus two), and Hormone Receptor (HR) status (positive versus negative) and if positive, previous CDK4/6 inhibitor therapy versus no CDK4/6 inhibitor therapy. IHC scores for HER2 expression were determined through central testing with the use of VENTANA HER2/neu investigational assay system, according to an algorithm adapted from the 2018 ASCO/CAP testing guidelines. Eligible patients must have received chemotherapy for metastatic disease or have had disease recurrence during or within 6 months after completing adjuvant chemotherapy. Patients with Hormone Receptor positive (HR-positive) disease must have received at least one line of endocrine therapy. Patients with treated, stable brain metastases were eligible. Patients were ineligible if they had a history of noninfectious interstitial lung disease treated with steroids or had suspected interstitial lung disease on imaging at screening. Both treatment groups were well balanced and approximately 89% in the ENHERTU® group and 90% in the chemotherapy group were HR-positive. The Primary end point was Progression Free Survival (PFS) among patients with HR-positive disease. Secondary end points included PFS among all patients, Overall Survival (OS) in the HR-positive cohort and among all patients, Objective Response Rate (ORR), Duration of Response, and efficacy in the HR-negative cohort. The median duration of follow up for survival was 18.4 months.

At the time of the primary efficacy analysis, the median PFS in the HR-positive cohort was 10.1 months in the ENHERTU® group and 5.4 months in the physician’s choice group (HR for disease progression or death=0.51; P<0.001). This benefit with ENHERTU® was seen consistently across all analyzed subgroups which included HER2 IHC 1+, HER2 IHC 2+ and ISH-negative, as well as those who had received previous treatment with CDK4/6 inhibitors. The median PFS among all patients was 9.9 months in the ENHERTU® group and 5.1 months in the physician’s choice group (HR for disease progression or death=0.50; P<0.001). The median PFS in the HR-negative cohort was 8.5 months in the ENHERTU® group and 2.9 months in the physician’s choice group (HR=0.46).

The median OS in the HR-positive cohort was 23.9 months in the ENHERTU® group and 17.5 months in the physician’s choice group (HR for death=0.64; P=0.003). The median OS among all patients was 23.4 months in the ENHERTU® group and 16.8 months in the physician’s choice group HR=0.64; P=0.001). The median OS in the HR-negative cohort was 18.2 months in the ENHERTU® group and 8.3 months in the physician’s choice group (HR=0.48).

The ORR in the HR-positive group was 52.6% in the ENHERTU® group and 16.3% in the physician’s choice group, and the median duration of response was 10.7 months in the ENHERTU® group and 6.8 months in the physician’s choice group. The ORR among all patients was 52.3% in the ENHERTU® group and 16.3% in the physician’s choice group. Among HR-negative cohort, the ORRs were 50% and 16.7% respectively.

Grade 3 or higher adverse events occurred in 53% of the patients who received ENHERTU® and 67.4% of those who received the physician’s choice of chemotherapy. Adjudicated, drug-related Interstitial Lung Disease or pneumonitis occurred in 12.1% of the patients who received ENHERTU®.

The authors concluded that this is the first Phase III, practice-changing trial of a HER2-directed therapy in patients with HER2-low metastatic breast cancer, to show a statistically significant and clinically meaningful benefit in PFS and OS, compared to standard chemotherapy, regardless of Hormone Receptor status, with a generally manageable safety profile. The authors added that the strong efficacy of ENHERTU® in this HER2-low patient population, with approximately 50% lower risk of disease progression and 36% lower risk of death with ENHERTU® compared to standard chemotherapy, supports the need to reclassify HER2-low as a new targetable category of metastatic breast cancer.

Trastuzumab Deruxtecan in Previously Treated HER2-Low Advanced Breast Cancer. Modi S, Jacot W, Yamashita T, et al. for the DESTINY-Breast04 Trial Investigators. N Engl J Med 2022; 387:9-20.

Late Breaking Abstract – ASCO 2022: KISQALI® with Switch Endocrine Therapy Following Progression on a Prior CDK4/6 Inhibitor in HR+/HER2-negative Metastatic Breast Cancer

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SUMMARY: Breast cancer is the most common cancer among women in the US and about 1 in 8 women (12%) will develop invasive breast cancer during their lifetime. Approximately 290,560 new cases of breast cancer will be diagnosed in 2022 and about 43,780 individuals will die of the disease, largely due to metastatic recurrence. Approximately 70% of breast tumors in patients with metastatic disease are Estrogen Receptor (ER) and/or Progesterone Receptor (PR) positive and HER2-negative. These patients are often treated with single agent endocrine therapy, endocrine therapy in combination with CDK4/6 inhibitor, or single agent chemotherapy.

Cyclin Dependent Kinases (CDK) play a very important role to facilitate orderly and controlled progression of the cell cycle. Genetic alterations in these kinases and their regulatory proteins have been implicated in various malignancies. Cyclin Dependent Kinases 4 and 6 (CDK4 and CDK6) phosphorylate RetinoBlastoma protein (RB), and initiate transition from the G1 phase to the S phase of the cell cycle. RetinoBlastoma protein has antiproliferative and tumor-suppressor activity and phosphorylation of RB protein nullifies its beneficial activities. CDK4 and CDK6 are activated in hormone receptor positive breast cancer, promoting breast cancer cell proliferation. Further, there is evidence to suggest that endocrine resistant breast cancer cell lines depend on CDK4 for cell proliferation and associated with increased expression of CDK4. The understanding of the role of Cyclin Dependent Kinases in the cell cycle, has paved the way for the development of CDK inhibitors.

KISQALI® (Ribociclib) is an orally bioavailable, selective, small-molecule inhibitor of CDK4/6, preferentially inhibiting CDK4 that blocks the phosphorylation of RetinoBlastoma protein, thereby preventing cell-cycle progression and inducing G1 phase arrest.

MAINTAIN trial is an investigator-initiated, multicenter, Phase II, double-blind, placebo-controlled, prospective randomized study, conducted to evaluate the efficacy of Fulvestrant or Exemestane with or without KISQALI®, in patients with HR+/HER2-negative metastatic breast cancer, who had previously progressed on any CDK 4/6 inhibitor plus any endocrine therapy. In this study, 119 evaluable patients were randomized 1:1 to receive either KISQALI® 600mg orally once daily given 3 weeks on and 1 week off plus switch endocrine therapy (N= 60) or placebo plus switch endocrine therapy (N=59). Patients treated with prior Fulvestrant received Exemestane as endocrine therapy in the randomization, whereas if prior Exemestane was endocrine therapy, patients received Fulvestrant. If patients received neither as prior endocrine therapy, Fulvestrant or Exemestane was given per investigator discretion, although Fulvestrant was encouraged. Ultimately, 83% of patients received Fulvestrant and 17% received Exemestane. Eligible patients were postmenopausal, had HR+/HER2- negative metastatic breast cancer and had progressed on prior endocrine therapy and any CDK4/6 inhibitor. With regards to prior CDK 4/6 inhibitor treatment, 84% received IBRANCE® (Palbociclib), 11% received KISQALI®, 2% received VERZENIO® (Abemaciclib) and 3% received IBRANCE® and another CDK 4/6 inhibitor. The median duration of treatment with the prior CDK4/6 inhibitor was 15.5 months in the KISQALI® group and 17 months in the placebo group. Approximately 60% of patients had visceral metastasis, 45% had de novo metastasis at diagnosis, 18% had bone-only disease, 18% had received 2 or more prior endocrine therapies for metastatic disease, and 9% had received chemotherapy. The Primary end point was Progression Free Survival (PFS) and Secondary end points included Overall Response Rate (ORR), Clinical Benefit Rate, safety, and tumor and blood biomarkers. The median follow up was 18.2 months.

There was a statistically significant PFS improvement for patients randomized to KISQALI® plus endocrine therapy and the median PFS for patients in the KISQALI® plus endocrine therapy was 5.33 months, compared with 2.76 months for patients receiving placebo and endocrine therapy (HR=0.56;; P=0.004). At 12 months, the PFS rates were 24.6% in the KISQALI® group versus 7.4% in the placebo group. Similar results were noted in the subset of patients treated with Fulvestrant and KISQALI®, and the median PFS for those randomized to KISQALI® was 5.29 months versus 2.76 months in the placebo group (HR=0.59; P=0.02). The PFS benefit was more evident in KISQALI® group compared to the placebo group, especially among those who received a shorter duration of therapy with a prior CDK4/6 inhibitor (HR=0.36) and among those over age 65 years (HR=0.31). The Overall Response Rate in the KISQALI® group was 20%, compared to 11% in the placebo group, and the median Duration of Response was 18.8 months in those treated with KISQALI® and endocrine therapy, compared with 14.8 months for those treated with placebo plus endocrine therapy. There was also a significant improvement in the Clinical Benefit Rate (CBR), defined as patients who achieved Complete Response, Partial Response, or stable disease lasting at least 24 weeks. The CBR was significantly improved in the KISQALI® group, compared with the placebo group, and was 43% versus 25%, respectively (P=0.06). The most common adverse event in the KISQALI® group was neutropenia at 72%, compared to 15% in the placebo group.

It was concluded from this randomized, placebo-controlled trial that, treatment with KISQALI® and an alternate endocrine therapy, after progression on a prior CDK4/6 inhibitor, showed a 43% reduction in the risk of progression or death, compared with placebo and endocrine therapy, in patients with HR+/HER2-negative metastatic breast cancer.

A randomized, phase II trial of fulvestrant or exemestane with or without ribociclib after progression on anti-estrogen therapy plus cyclin-dependent kinase 4/6 inhibition (CDK 4/6i) in patients (pts) with unresectable or hormone receptor–positive (HR+), HER2-negative metastatic breast cancer (MBC): MAINTAIN trial. Kalinsky K, Accordino MK, Chiuzan C, et al. J Clin Oncol 40, 2022 (suppl 17; abstr LBA1004). DOI: 10.1200/JCO.2022.40.17_suppl.LBA1004.