Several late-breaking studies made a splash today at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting. During the press conference this morning, results from the phase III MONALEESA-7 and KEYNOTE-062 trials were presented as well as long-term survival data from the KEYNOTE-001 trial. In the afternoon, a poster session featured a late-breaking study about the impact of the Affordable Care Act (ACA) in ovarian cancer.
Adding Ribociclib to Endocrine Therapy Improves Survival (Abstract LBA1008)
The addition of ribociclib, an oral CDK 4/6 inhibitor, to frontline endocrine therapy significantly extended overall survival (OS) for premenopausal women with advanced hormone receptor-positive/HER2-negative breast cancer, according to data from the phase III MONALEESA-7 trial.
Participants (N=672) were randomly assigned to received endocrine therapy plus ribociclib or endocrine therapy plus placebo. At a median follow-up of 34.6 months, 35% of patients in the ribociclib arm and 17% in the placebo arm were still receiving the assigned treatment.
The median OS was not yet reached for the ribociclib arm and 40.9 months for the placebo arm, resulting in a 29% relative reduction in risk of death for the ribociclib arm (HR=0.712; 95% CI, 0.535 – 0.948; P=0.00973). At 42 months of follow-up, the estimated OS rate was higher for the ribociclib arm compared with the placebo arm (70.2% vs 46.0%).
“This is the first time a statistically significant improvement in overall survival has been observed with a CDK 4/6 inhibitor in combination with endocrine therapy in patients with hormone receptor-positive advanced disease,” said study presenter Sara A. Hurvitz, MD, Director of the Breast Cancer Clinical Research Program at UCLA Jonsson Comprehensive Cancer Center.
Pembrolizumab in Gastric Cancer May be Safer Than Chemo (Abstract LBA4007)
Compared with chemotherapy, pembrolizumab alone had similar survival and less toxicity in the first-line setting for patients with PD-L1−positive, HER2-negative, advanced gastric or gastroesophageal junction (G/GEJ) cancer in the phase III KEYNOTE-062 trial. A survival benefit with pembrolizumab was seen in patients with tumors that had high PD-L1 expression—defined as a combined positive score of at least 10.
In terms of toxicity, 54.3% of patients who received pembrolizumab had a treatment-related adverse event and 16.9% had a grade 3 or higher adverse event. In contrast, 91.8% of patients who received chemotherapy had a treatment-related adverse event and 69.3% had a grade 3 or higher adverse event.
“For patients with advanced gastric or gastroesophageal cancer, pembrolizumab should really, in many cases, replace chemotherapy as a first-line treatment for this population,” said ASCO Expert Richard L. Schilsky, MD, Senior Vice President and Chief Medical Officer of ASCO.
5-Year Survival Rates for NSCLC Leap Forward with Pembrolizumab (Abstract LBA9015)
Pembrolizumab improved 5-year survival rates for advanced non-small cell lung cancer patients (NSCLC), according to long-term data from the multicohort phase Ib KEYNOTE-001 trial. At 5 years of follow-up, 18% of trial participants (100 of 550) were still alive. By comparison, before the advent of pembrolizumab, the average 5-year survival rate for advanced NSCLC was 5.5%.
Higher PD-L1 tumor proportion score (TPS) was linked to better survival, particularly among treatment-naïve patients—29.6% with a PD-L1 TPS of 50% or greater were still alive 5 years later compared with 15.7% with a PD-L1 TPS between 1% and 49%.
Among patients who received at least 2 years of pembrolizumab treatment and were still alive at data cutoff (n=46), the 5-year OS rate was 78.6% for treatment-naïve patients and 75.8% for previously treated patients. The objective response rate was 86% for treatment-naïve patients and 91% for previously treated patients.
ACA Linked to Better Diagnosis and Treatment of Ovarian Cancer (Abstract LBA5563)
After the implementation of the ACA in 2010, women with ovarian cancer had an increased likelihood of being diagnosed at an early stage and receiving treatment within 30 days of diagnosis, a poster reported.
The study researchers used data from the National Cancer Database and assessed early stage at diagnosis (I/II vs III/IV) and time to treatment (<30 days vs ≥30 days) in women aged 21 to 64 with ovarian cancer (n=72,987) and compared that to women aged 65 or older with ovarian cancer (N=59,499). The study time period defined 2006 to 2009 as before the ACA and 2011 to 2014 as after the ACA.
A difference-in-differences (DD) approach showed a trend toward increased diagnosis among younger women (DD=1.7%; 95% CI, 0.7 – 2.7; P=0.001) and reduction in delays in treatment of 30 days or greater (DD=−1.6%; 95% CI, −0.7 to −2.7; P=0.001) after the ACA was implemented.
“As stage and treatment are major determinants of survival, these gains under the ACA may have long-term impacts on women with ovarian cancer,” concluded the investigators.
Christina Bennett, MS