Unfazed by OS flop, Zai Lab eyes imminent China filing for MacroGenics' HER2 drug
MacroGenics’ anti-HER2 drug may have run into some trouble with its US data, but in China, partners at Zai Lab are getting a clear go-ahead signal.
The antibody, margetuximab, aced a bridging study among Chinese patients with advanced HER2 breast cancer, with a hazard ratio for progression-free survival of 0.69 favoring the combination of margetuximab plus chemotherapy, suggesting consistent safety and efficacy as seen in the global population. Zai Lab is now plotting a BLA submission by the end of the year — one year after MacroGenics scored its first FDA approval.
Closing the gap so that Chinese patients don’t fall behind those in the US and Europe in accessing cutting-edge drugs has been a key part of Zai Lab’s mission.
“The successful completion of our bridging study further demonstrates Zai Lab’s capabilities to produce clinical data of global quality to support regulatory approval in China in collaboration with our partners,” said Alan Sandler, president and head of global development, oncology.
Designed to share the same HER2 specificity with Roche’s blockbuster Herceptin, margetuximab, however, boasts an engineered Fc region that MacroGenics said can increase immune activation.
The SOPHIA trial, which had cemented its entry into the US market as Margenza, showed a 24% reduction in risk of disease progression or death over Herceptin (p=0.033), with a median PFS of 5.8 months for margetuximab.
But the latest data cut out of that Phase III trial has muddled the rosy picture. Not only did Margenza fail to hit its primary OS endpoint but it actually underperformed Herceptin in a third-line population. Margenza plus chemo posted a median OS of 21.6 months compared with a median OS of 21.9 months for patients in the Herceptin-chemo arm.
It’s unclear whether or how those results would affect Zai Lab’s prospects or plans in China.