Roche Holding Ltd.'s Perjeta showed a benefit of less than 1% to survival in a long-awaited late stage clinical trial of breast cancer patients, calling into question the Swiss group's aim to combine it with its blockbuster Herceptin medicine to bolster sales as the latter succumbs to generic rivals.
In data released at the close of the American Society of Clinical Oncologists meeting, Roche said its Perjeta breast cancer-based treatment did reduce the risk of invasive cancer returning compared with Herceptin and chemotherapy combination. However, the differential was negligible, at 94.1% compared with 93.2% for standard treatment of Herceptin and chemo.
"To an extent, this result was expected," said Deutsche Bank's Richard Parkes in a note. "But the low absolute size of benefit is still underwhelming."
The late-stage APHINITY trial compared 4,805 people with operable HER2-positive breast cancer over three years, half of whom were treated with chemotherapy, Perjeta and Herceptin while the other half had chemotherapy with placebo and Herceptin.
Perjeta is one of two drugs introduced by the Basel-based group to shore up its breast cancer franchise, and its combination with Herceptin forms part of Roche's strategy to fend off a cliff-edge drop in sales once Herceptin's sales exclusivity is successfully challenged. Amgen applied for a European regulatory permission to make a biosimilar in March.
"If Aphinity had been more positive, it would at least have given Roche the chance to bundle Herceptin and Perjeta in the neoadjuvant setting and set a competitive price in light of biosimilar competition," Steve McGarry, analyst at HSBC, wrote in a note. "That opportunity is now gone, leaving the HER2 breast cancer franchise more exposed to biosimilar competition." McGarry cut his price target for the Swiss pharmaceutical group to CHF215 per share from CHF230 per share, reiterating a "reduce" rating on the stock.
HER2-positive breast cancer is an aggressive form of the disease that affects 1 in 5 people diagnosed with breast cancer. Perjeta targets the HER2 receptor and is designed to prevent it from pairing with other HER receptors that help tumors to grow and survive. It is one of three cancer treatments Roche developed that target the HER2 pathway, along with Kadcyla and Herceptin. When combined with Herceptin, Perjeta is believed to create a stronger blockade of the signaling pathways, preventing tumor growth and cell survival, according to Roche.
Deutsche Bank's Parkes said his forecasts imply that Perjeta will capture 65% of the current Herceptin adjuvant market. "We expect Perjeta adjuvant use to be limited to the most at-risk patient populations and even here cost-benefit will remain a significant debate."