Foghorn Therapeutics’ Phase I dose escalation clinical trial of FHD-286 in relapsed and/or refractory acute myelogenous leukaemia (AML) and myelodysplastic syndrome (MDS) is under partial clinical hold by the Food and Drug Administration (FDA) has placed a partial clinical. 

The regulatory agency initiated the partial hold on the trial after death of a subject with potential differentiation syndrome was reported. A selective, allosteric and orally available, small-molecule, BRG1 and BRM enzymatic inhibitor, FHD-286 demonstrated anti-tumour activity across various malignancies including hematologic and solid tumours in preclinical studies.

Differentiation syndrome is linked to AML/MDS treatments that stimulate differentiation, an effect that is claimed to be on-target for FHD-286’s proposed mechanism of action. 

With the latest development, the FDA sought a review of the safety database, risk mitigation approaches and a breakdown of the clinical activity of the therapy across dose levels.

No new subjects will be enrolled in the trial until the FDA lifts the partial clinical hold.

Subjects who are presently enrolled and benefitting from therapy in the Phase I dose escalation trial of FHD-286 in AML/MDS could continue to receive the treatment.

The company noted that the latest partial clinical hold will not impact the Phase I dose escalation trial of FHD-286 in metastatic uveal melanoma (mUM), with enrolment underway as per the protocol.

Foghorn CEO Adrian Gottschalk said: “Patient safety remains our top priority. 

“We appreciate the dialogue with the FDA and will work diligently with the agency to resolve the partial clinical hold in AML/MDS as soon as possible.”

Furthermore, the company will suspend the guidance on the timing for reporting findings from the dose escalation phase of the FHD-286 programme until the partial clinical hold for the AML/MDS trial is resolved.

A malignancy of the blood and bone marrow, AML is the most common kind of acute leukaemia in adults.