Roche affiliate Chugai files for T-DM1 approval in Japan; gains rights to Afraxis compound

Japanese drugmaker Chugai Pharmaceutical (TYO: 4519), which is majority owned by Swiss major Roche (ROG: SIX), has filed a New Drug Application to the Ministry of Health, Labor and Welfare (MHLW), for antibody-drug conjugate trastuzumab emtansine (T-DM1) for the treatment of HER2-positive metastatic or recurrent breast cancer. Roche has already filed for approval of T-DM1 in both the USA and Europe (The Pharma Letter October 16, 2012).

Chugai filed the application with the MHLW based on the results from an overseas phase III clinical trial (the EMILIA trial) and a domestic Phase II clinical trial. The EMILIA trial is an international phase III study comparing T-DM1 alone to lapatinib in combination with capecitabine in people with HER2-positive metastatic or unresectable locally advanced breast cancer who had previously been treated with trastuzumab and a taxane chemotherapy. Japanese patients were not included in the EMILIA trial.

The EMILIA trial had progression free survival (PFS) as one of its primary endpoints, and patients who received T-DM1 experienced a 35% reduction in the risk of their disease worsening or death compared to those who received lapatinib plus capecitabine. The median PFS improved by 3.2 months from 6.4 months of lapatinib and capecitabine to 9.6 months of T-DM1 (hazard ratio=0.65; p<0.0001).