Merus bags its first approval

Merus has got an accelerated FDA nod for its anti-HER2 x HER3 bispecific antibody zenocutuzumab in second-line pancreatic or non-small cell lung cancers with NRG1 gene fusions. However the drug, now known as Bizengri, hasn’t been a big focus for a while, and earlier this month Partner Therapeutics agreed to commercialise the asset for an undisclosed fee. The presumably small deal can be explained by the fact that NRG1 fusions are seen in less than 1% of cancers. Merus had originally hoped to file zenocutuzumab for a tumour-agnostic indication; it has previously said that it might later file for a broader label. A decision on Bizengri, which had priority review, had been expected in November, but the FDA extended the review period to 4 February, saying it needed more time to consider Merus’s response to a CMC request. Bizenga’s label carries warnings of infusion-related reactions, interstitial lung disease and left ventricular dysfunction, but the FDA clearly decided that these risks were outweighed by ORRs of 40% in pancreatic and 33% in NSCLC. Merus’s stock opened up just 1%; its $3bn market cap is largely driven by the anti-EGFR x LGR5 bispecific petosemtamab, which recently went into phase 3.