Roche has been boosted by the news that the US Food and Drug Administration has given the green light to Perjeta, a new personalised medicine for previously-untreated HER2-positive metastatic breast cancer.

Perjeta (pertuzumab) is combined with Roche's blockbuster anti-HER2 therapy Herceptin (trastuzumab) and the chemotherapy docetaxel. It is administered intravenously and works by targeting a different part of the HER-protein than Herceptin, resulting in further reduction in growth and survival of HER2-positive breast cancer cells.

The approval, following a priority six-month review, is based on data from the Phase III study, called Cleopatra, which showed that people with previously untreated HER2-positive metastatic breast cancer who received the combination of Perjeta, Herceptin and docetaxel lived 6.1 months longer without their cancer getting worse compared to Herceptin plus docetaxel (ie median progression-free survival of 18.5 versus 12.4 months).

Production issues

However, the FDA noted that "there are production issues that potentially could affect the long-term supply" of Perjeta and limited its approval to product that has not been affected by those problems. Roche's Genentech unit has agreed to post-marketing commitments related to the manufacturing process for Perjeta, including FDA review of data from "the next several productions of the medicine".

Patrick Yang, head of Roche's pharma global technical operations, said that "we expect to meet demand for Perjeta", but noted that "we recently identified a cell growth issue that might affect our future supply". He added that "we take this very seriously and are working with the FDA to ensure a consistent manufacturing process".

Janet Woodcock, director of FDA’s Center for Drug Evaluation and Research, said that "given the need for additional treatments for metastatic breast cancer, we made the decision to approve this drug and not to delay its availability to patients pending resolution of the production issues".  Roche's chief medical officer Hal Barron stated that the approval is an important advance and "we are very pleased to see our efforts in studying the science of HER2 translate into another personalised medicine".

Roche noted that this year an estimated 226,870 women will be diagnosed with breast cancer, and 39,510 will die from the disease. About 20% of breast cancers have increased amounts of the HER2 protein and the company is also working on a third drug for HER2-positive breast cancer, T-DM1.

Data from a Phase III trial of T-DM1 (trastuzumab emtansine), which combines Herceptin with partner ImmunoGen's chemotherapy DM1, generated much excitement at the American Society of Clinical Oncology meeting in Chicago last weekend.