Genentech’s Perjeta-Based Adjuvant Breast Cancer Care Shows Minor Improvement, Puma Biotech Shares Jump

Published: Jun 06, 2017

Genentech’s Perjeta-Based Adjuvant Breast Cancer Care Shows Minor Improvement, Puma Shares Jump June 6, 2017
(Last Updated: June 6, 2017 at 12:20pm PT)

By Alex Keown, BioSpace.com Breaking News Staff

CHICAGO – Data from Genentech ’s combination study of Herceptin and Perjeta as adjuvant care for breast cancer patients failed to wow investors and pharma watchers at the American Society of Clinical Oncology annual meeting.

During the annual event in Chicago, Genentech revealed data that showed a combination of Herceptin, the go-to drug for HER2-positive breast cancer, and Perjeta, demonstrated positive results in staving off a return of breast cancer in a vast majority of patients. In its announcement, Genentech said that 94.1 percent of people treated with the Perjeta-based regimen did not have their breast cancer return after three years. That’s an impressive number, however it’s only slightly better than a combination of Herceptin and traditional chemotherapy. Using the more traditional route, 93.2 percent of patients did not see their cancer return—a difference of .9 percent.

That difference was enough to give shares of Puma Biotechnology a boost on Monday a nice bump as that company awaits a decision from the U.S. Food and Drug Administration on whether it will approve its experimental breast cancer drug neratanib, a potent irreversible tyrosine kinase inhibitor. In late May, an FDA advisory committee recommended approval for the drug in a 12-4 vote, although there were some calls for a narrowing of the drug’s label should it be approved. During clinical trials, neratanib along with Herceptin demonstrated a disease-free survival (DFS) rate of 93.9 percent.

While things look good for Puma, Dietmar Berger, M.D., Ph.D., Senior Vice President, Global Head of Hematology/Oncology Clinical Development, Genentech reached out in an email and told BioSpace that its Perjeta-based regiment “improved upon the high bar” set by Herceptin in the treatment of HER2-positive breast cancer patients.

“Despite advancements in the treatment of HER2-positive early breast cancer, one in four people treated with Herceptin and chemotherapy will eventually see their cancer return in the long-term. Treating breast cancer early, before it has spread, may help prevent the disease from returning and potentially reaching an incurable stage,” the Genentech spokesperson said in an email.

There was no indication of what a possible Perjeta-based regimen for adjuvant breast cancer care will cost and Genentech did not provide any insight into what that cost could be. But, it’s a sure bet that the pricing will be significantly more than the traditional Herceptin and chemotherapy regimen. If that does prove to be the case, there will be a question as to how many doctors push patients onto the treatment over the .9 percent difference.

At four years, the data for the Perjeta-based regimen is a bit better compared to Herceptin and chemotherapy. At four years, 92.3 percent of patients treated with the Perjeta-based regimen did not have their breast cancer return compared to 90.6 percent treated with Herceptin and chemotherapy.

In HER2-negative patients, the Perjeta-based regiment also showed strong results, holding off a cancer recurrence in 92 percent of patients in comparison to 90.2 percent in Herceptin and chemotherapy groups. In contrast, Puma’s drug was not as strong in HER2-negative patients, according to reports.

In a statement Sandra Horning, Genentech’s chief medical officer, said the goal of adjuvant care is to provide the best chance for a cure for cancer patients. She said in her statement that the company comes closer to that goal with each advance, including the Perjeta-based regimen.

“In early breast cancer, where the standard of care treatment has already significantly improved clinical outcomes, some people can live for many years without recurrence. The accumulation of invasive disease-free survival events is therefore gradual,” the Genentech spokesperson said in an email to BioSpace. “Study participants will be followed for ten years and future analyses with longer follow-up will be important to provide additional insights into the role of these treatments in the adjuvant setting.”

One area where the Genentech cocktail may be more palatable to patients is in the safety profile. Puma’s neratanib comes with one significant side effect—severe diarrhea. Genentech said the Perjeta-based regimen’s safety profile has remained consistent with previous studies, including a low incidence of cardiac events and no new safety signals.

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