FDA Halts Mersana's Early-Stage Cancer Trial After Patient Death

Mersana Therapeutics Inc's MRSN Phase 1 trial of XMT-2056 has been placed on clinical hold by the FDA.
This action follows the company's communication to FDA that Mersana was voluntarily suspending the trial due to a recent Grade 5 (fatal) serious adverse event (SAE) that was deemed related to XMT-2056.
The SAE and its cause remain under investigation.
XMT-2056 is Mersana's first Immunosynthen STING-agonist ADC product candidate to enter the clinic.
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The SAE occurred in the second patient enrolled at the initial dose level in the dose escalation portion of the Phase 1 trial in previously treated patients with HER2+ recurrent or metastatic solid tumors.
"With the clinical hold in place, our efforts for XMT-2056 are now focused on undertaking the work required to fully analyze this SAE and consider potential next steps for development," said Anna Protopapas, President and Chief Executive Officer of Mersana Therapeutics.
Price Action: MRSN shares are down 3.46% at $4.46 on the last check Monday.