FDA clinical hold causes Unum Therapeutics shares slump

Shares of US clinical-stage drug developer Unum Therapeutics (Nasdaq: UMRX) tumbled as much as 23% after the company revealed that the Food and Drug Administration had placed a "clinical hold" on the Phase I trial of its cancer treatment ACTR087.

Phase I trial (ATTCK-20-2) is evaluating Unum’s ACTR087 in combination with rituximab following lymphodepleting chemotherapy with fludarabine and cyclophosphamide in patients with relapsed/refractory CD20+ B cell non-Hodgkin lymphoma (r/r NHL).

The clinical hold was initiated following the submission of a safety report by Unum to the FDA regarding one patient in the safety expansion cohort of the trial (Cohort 3) who recently experienced serious adverse events that included Grade 3 neurotoxicity and cytomegalovirus (CMV) infection, and Grade 4 respiratory distress.