Invited discussant of the MONALEESA-3 trial, Mafalda Oliveira, MD, PhD, of Vall d’Hebron University Hospital and Vall d’Hebron Institute of Oncology, Barcelona, commented: “I totally agree with the authors when they say these results are ‘impressive.’” Among all the phase III trials evaluating combinations of CDK4/6 inhibitors and endocrine therapy, MONALEESA-3 has shown the longest median overall survival in a first-line population: 67.6 months, she added.

Mafalda Oliveira, MD, PhD

MONALEESA-3 included patients with de novo advanced disease and those whose disease recurred at least 12 months following adjuvant endocrine therapy. Based on data suggesting that patients with de novo disease typically fare better, she wondered whether outcomes for these two subsets differed. However, in the question-and-answer period, Dr. Patrick Neven indicated their hazard ratios are similar.

“Another thing worth mentioning is that only 35% of patients in the placebo group received subsequent CDK4/6 inhibitors. Perhaps this does not reflect the current treatment landscape in this context,” she added.

The overall difference of nearly 16 months between the experimental and control arms is much greater than the differences observed in trials of the other agents, which have ranged from approximately 11 to 12 months in the first-line setting and 7 to 9 months in intent-to-treat populations, Dr. Oliveira noted. “The overall survival results of -PALOMA-2 (palbociclib plus letrozole vs letrozole alone) were released at this year’s ASCO Annual Meeting, and I look forward to including that data together with the MONALEESA-3 in this treatment landscape,” she said. 

DISCLOSURE: Dr. Oliveira reported financial relationships with Roche, GSK, Gilead, Puma Biotechnology, AstraZeneca, iTeos Therapeutics, Pierre-Fabre, MSD Novartis, and Eisai.