John T. Cole, MD

“The end-of-study analysis of the CLEOPATRA trial demonstrates and confirms the long-term benefit of combined HER2-antibody therapy, with a significant number of ongoing responders,” said John T. Cole, MD, breast cancer specialist and Director of Clinical Cancer Research at Ochsner Health System in New Orleans.

He has witnessed this benefit first-hand, he told The ASCO Post. “I have multiple patients in my practice who have exceeded 50 cycles of therapy—several with ongoing responses, and one in a patient who has received more than 100 cycles,” he said. “I have one patient who decided to stop treatment after several years and relapsed. She is back on treatment and doing well.”

Dr. Cole does not discontinue pertuzumab/trastuzumab in patients still responding, since biomarkers to guide such a decision are lacking, he said, but he acknowledges the downside of continuous treatment: “The big issue with a successful therapy is cost,” he said. “We are not talking about 1 year but rather many years of therapy. That really adds up.”

Improving Outcomes in HER2-Positive Disease

Carlos H. Barrios, MD, of the Centro de Pesquisa Clínica em Oncologia and Latin American Cooperative Oncology Group in Porto Alegre, Brazil, discussed other studies of anti-HER2 therapies at the ASCO meeting and shared some observations. “Anti-HER2 treatment has led to remarkable improvements in overall results for patients with HER2-positive breast cancer,” he said. Several clinical trials have now shown that outcomes are steadily improving for this subtype of breast cancer—an observation that cannot be made for all breast cancer subtypes.

Carlos H. Barrios, MD

One of the most important consequences of these results is that real-world data reported by Delalogue et al at the 2017 ASCO Annual Meeting do show consistent survival in HER2 positive patients treated in clinical practice outside trials. “In 2008, the median survival for metastatic HER2-positive breast cancer was 39 months, and by 2012, it reached 51 months. It is probably better today.It is reassuring that what we observe in trials is being translated to clinical practice,” Dr. Barrios said.

Looking ahead, Dr. Barrios predicted outcomes can be further improved, “but the complexity and plasticity of this vital signaling pathway will probably require a combination of different strategies to have a more definitive impact in addicted tumor cells. Better understanding of resistance mechanisms as well as the development of biomarkers and patient selection strategies are essential for further improvements.” ■

DISCLOSURE: Dr. Cole reported no conflicts of interest. Dr. Barrios owns stock in BioMarker, MedSIR, and Tummi; has received honoraria from Boehringer Ingelheim, Eisai, GlaxoSmithKline, Novartis, Pfizer, Roche/Genentech, and Sanofi; has consulted or advised for AstraZeneca, Boehringer Ingelheim, Eisai, GlaxoSmithKline, Libbs, MSD Oncology, Novartis, Pfizer, Roche/Genentech, and United Medical; has received travel expenses from AstraZeneca, Bristol-Myers Squibb Brazil, MSD Oncology, Novartis, Pfizer, and Roche/Genentech; and has received research funding from AB Science, AbbVie, Abraxis BioScience, Amgen, Asana Biosciences, Astellas Pharma, AstraZeneca, Atlantis Clinica, BioMarin, Boehringer Ingelheim, Bristol-Myers Squibb, Celgene, Covance, Daiichi Sankyo, Exelixis, GlaxoSmithKline, Halozyme, ImClone Systems, INC Research/inVentiv Health, Janssen, LEO Pharma, Lilly, Medivation, Merck, Merrimack, Millennium, Mylan, Novartis, Pfizer, Roche/Genentech, Sanofi, and Taiho Pharmaceutical.