Pfizer adds to its rare disease portfolio with purchase of Therachon, a Swiss company working in achondroplasia. But whether it can catch up with Biomarin’s Phase III vosoritide is still to be seen.

Once expected to be absorbed by Sanofi, US biotech Warp Drive Bio now will become part of California’s Revolution Medicines in a stock transaction. Sosei elects against its option to acquire MiNA Therapeutics; MeiraGTX follows its June IPO with takeout of Vector Neurosciences. Other recent mergers and acquisitions...