Mersana Therapeutics announced that the FDA has lifted the partial clinical hold on the Phase 1 study of XMT-1522. Mersana and the FDA reached alignment on changes to the protocol, including increased monitoring as well as the exclusion of patients with advanced hepatic impairment. Although XMT-1536, Mersana's Dolaflexin ADC targeting NaPi2b, was not subject to a clinical hold, Mersana has decided to implement similar modifications to the XMT-1536 protocol. In addition, alternative dosing regimens will be evaluated for both clinical trials.The XMT-1522 trial will begin with a once-every-four-week dose regimen. This dosing regimen has already been implemented in the XMT-1536 trial at previously explored dose levels in order to enable a comparison of relevant doses and their impact on the safety, efficacy and PK profile of the drug candidate. The company may evaluate additional regimens as well. Data on XMT-1536 is expected in the first half of 2019.
