Marker Therapeutics provides update on observations from Phase 1 APOLLO study

Marker Therapeutics (MRKR) provided an update on the progress and clinical observations from the Phase 1 APOLLO study. The Company’s Phase 1 APOLLO study is a multicenter, open-label clinical study investigating MT-601, a Multi-Antigen Recognizing-T cell product, in patients with lymphoma who have relapsed after anti-CD19 CAR-T cell therapy or for whom anti-CD19 CAR-T cell therapy is not an option. Today, Marker is reporting an update on the safety and efficacy data from the dose escalation portion of the study showing a favorable safety profile across all evaluated doses and a 66% objective response rate in patients with NHL, with 50% demonstrating complete response. A total of 24 B-cell lymphoma patients have been treated with MT-601 across 7 U.S. clinical sites, including 15 patients with Non-Hodgkin Lymphoma and 9 patients with Hodgkin Lymphoma. At the time of the data cutoff, 12 NHL and 9 HL patients have been assessed. Patients with NHL and HL received doses ranging from 100×106-400×106 cells and showed objective responses and a favorable safety profile. The 12 NHL patients received doses ranging from 100×106-200×106 cells and had undergone multiple lines of therapy, including anti-CD19 CAR-T cells and bispecific antibodies; dual exposed patients. 8 out of 12 NHL patients had objective responses, with 6 patients demonstrating complete response as best response. Durable responses were observed with 5 patients showing continued response greater than or equal to6 months, including 3 patients with greater than or equal to12 months durability. HL patients received doses ranging from 200×106-400×106 cells and had undergone a median of 8 prior lines of therapy. Seven out of 9 HL patients had objective responses, with 1 patient demonstrating CR highlighting the versatility of MT-601 across multiple histologies. The dose escalation portion of the study tested doses ranging from 100×106-400×106 cells in patients with B-cell lymphoma. To date, no DLTs have been reported at the highest dose. Infusion of MT-601 was well tolerated in all study participants, with no observation of ICANS and two reported Grade 1 cytokine release syndrome events. Patients were treated with or without lymphodepleting chemotherapy prior to receiving infusions of MT-601. No change in DLTs or ICANS was observed between patients treated with and without lymphodepletion. Data collected from the 24 patients treated demonstrated a robust safety profile with no reported serious adverse events reinforcing the benefit of MT-601. The Phase 1 APOLLO study is composed of a dose escalation phase, followed by a dose expansion phase. The dose escalation cohort evaluated the safety and optimum dose level of MT-601 with doses ranging from 100×106-400×106 cells. On June 17, the Safety Review Committee cleared the pre-specified maximum dose for the dose expansion portion of the trial. The dose expansion will enroll patients with DLBCL who have relapsed after anti-CD19 CAR-T cells or who are ineligible for CAR-T therapy.