Editor's Note: For more coverage from the conference, check out our round-up — ASCO 2017: What you missed.
- A closely watched study of nearly 5,000 women with HER2 positive breast cancer showed adding Roche’s Perjeta (pertuzumab) to post-surgery treatment with the Swiss drugmaker’s Herceptin (trastuzumab) helped lower the risk of developing invasive disease.
- Patients who received both drugs together had a 19% lower risk of recurrence of invasive disease or death compared to those who were treated with Herceptin alone. While the benefit was statistically significant, the question for Roche is whether the risk reduction is sufficient to convince physicians to prescribe the combination rather than the already beneficial Herceptin monotherapy.
- Herceptin is a top earner for Roche, pulling in sales of 6.7 billion Swiss francs (roughly $6.75 billion). But inbound biosimilar competition could begin to erode its strong market position. Success with Perjeta, as both a single agent and in combination, will therefore be important for future growth of Roche’s HER2 franchise.
Herceptin transformed the standard of care for HER2 positive breast cancer, greatly improving outcomes in a patient population estimated to account for about 20% of the overall breast cancer population in the U.S.
Roche developed Perjeta as a successor to Herceptin and the drug has already found a niche in treatment of early breast cancer before surgery. The APHINITY study will likely improve upon that performance, although the benefit seen may not be as high as some have hoped.
Study results will be presented Monday morning at the annual meeting of the American Society for Clinical Oncology (ASCO).
With a median follow-up of almost four years, 171 patients on Perjeta and Herceptin developed invasive breast cancer, compared to 210 patients for those on Herceptin and placebo.
At the three year mark, 94.1% of women on Herceptin and Perjeta had not developed invasive disease, compared to 93.2% who were treated with Herceptin alone — a roughly one percentage point improvement.
"The study, APHINITY, was designed to look for about a 2.5% improvement in disease recurrence," said Dr. Harold Burstein, an ASCO expert and medical oncologist at Dana-Farber Cancer Institute and Brigham & Women's Hospital. "In the end, it fell short of that, presumably because a lot of the patients did so well."
A greater difference between treatment groups in three-year invasive disease-free survival was seen in patients with node-positive breast cancer: 92% vs 90.2%, respectively.
"I think that the benefits are sufficiently narrow that we are probably going to think about this drug mostly in higher risk patients, that would be node-positive patients or tumors that are larger where there is still sufficient risk and you'd want to offer something more than exists currently," Burstein added.
The results also raise the question of cost, as adding Perjeta to Herceptin would likely increase the cost of treatment even the two are packaged together to payers. Add in the prospect of a cheaper biosimilar from Mylan winning approval in the near future, and physicians and payers could see value in a lower-cost version of Herceptin.
APHINITY has already had an impact on markets. When Roche announced the trial met statistical significance back in March, the news boosted the pharma's shares while delivering a blow to Puma Biotechnology. Puma is hoping to win U.S. approval for its drug neratinib, also in adjuvant treatment of HER2 positive breast cancer patients who initially received Herceptin.
Roche’s success in APHINITY, even if short of a slam-dunk, could make it harder for Puma to carve out a space in the market, if neratinib is approved. In late May, an advisory panel to the Food and Drug Administration recommended that the agency approve neratinib by a vote of 12 to four.
Roche plans to discuss the study results with the FDA and the European Medicines Agency, in hopes of converting Perjeta’s current accelerated approval in early breast cancer to a full approval.