Harold Burstein, MD

Several breast cancer experts weighed in on the findings of the APHINITY trial. At an ASCO press briefing, Harold Burstein, MD, Associate Professor of Medicine at Harvard Medical School and breast cancer specialist at Dana-Farber Cancer Institute, Boston, pointed out that investigators estimated a 10% risk of recurrence and a 20% reduction in risk with dual targeting. “They came close to these targets,” he noted.

“These are clinically meaningful results for many patients with HER2-positive breast cancer,” Dr. Burstein maintained, especially those with high-risk factors. In stage 1 HER2-positive disease, in contrast, “it probably does not make sense to add this or any other therapy beyond existing trastuzumab [Herceptin] and chemotherapy because of the very good prognosis for such patients.”

“APHINITY is a step forward in the treatment of HER2-positive breast cancer, and the relatively narrow benefits you are seeing in numerical terms reflect the overall good prognosis of HER2-positive early breast cancer now,” he concluded.

Cost Implications

The study’s discussant, Carey Anders, MD, Associate Professor of Medicine at the University of North Carolina at Chapel Hill, said that although clinicians “may consider” pertuzumab (Perjeta) plus trastuzumab in high-risk patients, this comes at a high financial cost. Pertuzumab adds almost $100,000 to the cost of a course of treatment, by Medicare estimates. Although 1 year of dual HER2 blockade costs $150,504, trastuzumab alone comes in at $55,908. “The cost implications are quite substantial,” she said. “We are all struggling with this.”

William Sikov, MD

William Sikov, MD, Program in Women’s Oncology at the Women and Infants Hospital of Rhode Island and Associate Professor of Medicine at the Alpert Medical School of Brown University, Providence, also questioned the value of adding pertuzumab or other costly treatments to adjuvant chemotherapy and trastuzumab and was applauded during the session. “To treat 100 patients with pertuzumab on top of standard therapy would cost $10 million dollars. With a 2% improvement, this means paying $5 million for each patient who does not recur, and the study will never demonstrate a survival advantage. I can think of a lot better things to do with $5 million [of health-care dollars],” Dr. Sikov commented.

“The problem is that we don’t live in utopia, where treatments have no financial or toxicity costs,” he continued. “Until we have more robust clinical or biologic indicators for which patients are going to benefit from these treatments, it would be irresponsible to add these to our standard regimens for a wide range of patients who are at slightly higher risk. These are patients who do very well with standard therapy.”

All experts emphasized the need to identify subgroups who may benefit from dual HER2 targeting, and APHINITY aims to do so. “We now have a huge amount of biomaterial, and work is ongoing on biomarkers. I hope to find subgroups where we see the most prominent effect of these agents, so we can better select the right patients for treatment,” Dr. von Minckwitz said. ■

DISCLOSURE: Drs. Burstein, Anders, and Sikov reported no conflicts of interest.