US
regulators have approved Roche’s new breast cancer drug after granting it a
priority review to speed up the process. The FDA says Perjeta (pertuzumab) can now be used with Roche’s Herceptin
(trastuzumab) and docetaxel chemotherapy for patients with HER2-positive
metastatic breast cancer (mBC) who have not been treated before.
The approval is based on the pivotal Phase III CLEOPATRA study, which showed this combination increased median progression-free
survival by an extra 6.1 months, compared to patients receiving Herceptin and
chemotherapy alone (median PFS was 18.5 against 12.4 months).
Part of a wave of personalised medicines, the drug gives people with this
aggressive form of breast cancer more time
without their disease worsening. Patients also experienced a 38% reduction in the risk of their cancer
worsening or death, the study showed.
However, the FDA said it wants a review of data from the next few
productions of the medicine after Roche identified what it calls a “cell growth
issue that might affect our future supply of the medicine”. “We take this very seriously and are working with the FDA to ensure a
consistent manufacturing process that maintains drug supply for the people who
need it,” said Patrick Yang, Roche’s head of pharma global technical
operations.
Herceptin is one of Roche’s biggest selling drugs, and brought in CHF5.3
billion ($5.8 billion) last year, but will start to lose its patent protection
soon. Pertuzumab is expected to make $1.8 billion in peak annual sales.
New mode of action
Perjeta is an HER2 dimerisation inhibitor, which Roche says is designed to
prevent the HER2 receptor from pairing (dimerising) with three other HER
receptors. The HER2 receptor protein is found in high quantities on the outside of
cells in HER2-positive cancers and Perjeta is thought to block cell signalling,
which may inhibit cancer cell growth or lead to the death of the cancer
cell.
The mechanisms of action of Perjeta and Herceptin are believed to be
complementary as both bind to different regions of the HER2 receptor.
“Based on the way the two medicines work together, the combination plus
chemotherapy can prolong the time before this aggressive cancer worsens
compared to Herceptin and chemotherapy alone,” said Hal Barron, Roche’s chief
medical officer.
The European Medicines Agency is currently reviewing the drug in the same
combination with the same patient group. In addition the EMA is looking at it in patients with locally recurrent,
inoperable breast cancer, who have either not received previous treatment or
whose disease has returned after early-stage treatment.