Curis’ phase 1/2a leukaemia study is the latest to join the club of FDA clinical holds, following the death of a trial participant.

The Massachusetts-based biotech announced the partial clinical hold today, citing the FDA’s request for additional safety and efficacy data, including more information about the patient death.

The trial on pause is TakeAim Leukemia, which is studying different doses of orally-administered emavusertib — an IRAK4 kinase inhibitor — as monotherapy in combination with azacitidine or venetoclax for patients with relapsed or refractory acute myeloid leukaemia (AML) or high-risk myelodysplastic syndrome.

After a patient in the study died as a result of multiple conditions, one of them being rhabdomyolysis, the FDA is asking Curis to pause enrollment of new participants. Rhabdomyliosis is the breakdown of muscle and is a known side effect of high doses of emavusertib.

“Given the clinical profile of emavusertib observed to date, we are hopeful that the study can be resumed soon, after appropriate review,” Curis CEO James Dentzer said in a statement. Curis will share an update on the timing of talks about a path to market for emavusertib once the impact of the hold on the trial is clearer.

Grade 3 rhabdomyolysis cases have been observed at the 300-mg, 400-mg and 500-mg doses of the drug. The company chose 300 mg as the phase 2 dose.