Molecular Templates provides interim update on its programs

Molecular Templates provided an update on its programs. MT-6402: The Part A dose escalation of the phase I study for MT-6402 has been completed with no Grade 4 or Grade 5 drug-related adverse events observed to date. 1 patient with a PD-L1 TPS of 2% who had progressed after chemotherapy, radiation therapy, and pembrolizumab had a confirmed PR with 70% tumor reduction and remains on study in cycle 18. 1 patient with a PD-L1 CPS of 10% who had progressed after three previous lines of therapy, including progression on Ipi/Nivo within 4 months, showed deepening tumor reduction over time of 3%, 9%, and 15% at the end of cycles 2, 4, and 6, respectively. At the end of cycle 8, the patient had an unconfirmed PR with a 37% reduction in tumor size. The patient remains on study in cycle 9. 1 patient with a PD-L1 CPS of 5% who had progressed after six prior lines of therapy and was refractory to pembrolizumab received 2 doses of MT-6402 before coming off treatment due to the treating physician’s concerns around an asymptomatic grade 1 high sensitivity troponin elevation and hyponatremia related to excessive alcohol intake. The patient discontinued treatment, but a subsequent CT scan assessed by an external radiology review showed that the patient had a 36% tumor reduction. 1 patient with a PD-L1 CPS of 10% with pre-existing cardiac risk factors of hypertension, hyperlipidemia, and hypercholesterolemia received three doses of MT-6402 before presenting with asymptomatic grade 1 high sensitivity troponin elevation and dosing was held. A CT scan showed a 13% reduction in tumor size, but disease progression occurred during treatment interruption and patient discontinued at the end of cycle 6. MT-8421: MT-8421 is designed to potently destroy CTLA4+ Tregs via enzymatic ribosome destruction but does not have activity against low CTLA-4 expressing peripheral Tregs. Three patients were dosed in the first cohort of the phase I study at 32 mcg/kg. No grade 3 or grade 4 drug-related adverse events were observed. Two patients have stable disease and remain on study at cycle 4 and cycle 2, respectively. One patient had disease progression at the end of cycle 2. Enrollment is on-going in the second cohort of 48 mcg/kg for the phase I study of MT-8421. MT-0169: A phase 1 study in patients with relapsed or refractory multiple myeloma was closed on Dec 2023 due to slow patient enrollment in the wake of multiple new approvals in myeloma. MTEM plans on initiating an investigator sponsored trial with MD Anderson Cancer Center to evaluate MT-0169 in relapsed or refractory CD38+ AML patients.