Oncternal Therapeutics, Inc. updated the status of its dose escalation/dose expansion Phase 1/2 Study ONCT-808-101, evaluating the company's ROR1-targeting autologous CAR T cell therapy ONCT-808 for the treatment of patients with relapsed or refractory aggressive B-cell lymphoma, including patients who have failed previous CD19 CAR T treatment. At the initial dose of 1x106 CAR T cells per kg, two of the three patients achieved complete metabolic response (CMR) and the third achieved a partial response (PR) by FDG PET-CT. Common adverse events in this dosing cohort included decreased blood counts, pneumonia and Grade 1-2 cytokine release syndrome (CRS) as of a 4 December 2023 data cutoff.

The first patient treated at the second dose level of 3x106 CAR T cells perkg, an 80-year-old with bulky disease who had received four previous lines of therapy including CD19 CAR T, experienced a Grade 5 (fatal) serious adverse event consistent with CRS and immune effector cell-associated neurotoxicity syndrome (ICANS). No evidence of his lymphoma was found histologically, based on the patient's initial autopsy report. Oncternal has been in communication and is aligned with the Food and Drug Administration (FDA) on proposed protocol changes that include modified eligibility criteria and testing lower doses of ONCT-808 for future patients in the study.