MT-5111

P1, N=50, Terminated, Molecular Templates, Inc. | N=178 --> 50 | Trial completion date: May 2025 --> Apr 2023 | Recruiting --> Terminated; Study Reprioritization

Three ETBs (MT-0169, MT-5111, and MT-6402) are currently in clinical studies across different targets (CD38, HER2, PD-L1) and across hematologic malignancies, solid tumor, and immuno-oncology indications. ETBs can also deliver additional payloads to drive unique biology like the alteration of tumor immunophenotype. Here we describe three active clinical stage programs with encouraging safety and efficacy data that represent a transformation of the immunotoxin landscape into a more viable therapeutic approach to target validated as well as typically intractable clinical cancer targets.

MT-5111 is a 55kD engineered toxin body targeting HER2 in solid tumors that binds to an epitope distinct from trastuzumab and pertuzumab, offering potential combination strategies with other HER2-targeting agents. sHER2 biomarker data is expected for all cohorts with PK correlation and 23µg/kg safety and efficacy data. PK profile of MT-5111, C1D1 values

P1, N=140, Recruiting, Molecular Templates, Inc. | Phase classification: P1/2 --> P1

Background: MT-5111 is a 55kD engineered toxin body (ETB) targeting HER2 in solid tumors that binds to an epitope distinct from trastuzumab and pertuzumab, offering potential combination strategies with other HER2-targeting agents. MT-5111 is well tolerated to-date with no clinically significant immuno/cardiotoxicity. Dose escalation is ongoing at a dose of 13µg/kg, expected to be required for efficacious exposure.

P1/2, N=178, Recruiting, Molecular Templates, Inc. | Phase classification: P1 --> P1/2

Background : MT-5111 is a 55 kD engineered toxin body (ETB) targeting HER2 in solid tumors that binds to an epitope distinct from trastuzumab and pertuzumab, offering potential combination strategies with other HER2-targeting agents. MT-5111 was well tolerated with no clinically significant immuno/cardiotoxicity. Dose escalation is ongoing and is nearing levels expected to be required for efficacious exposure.

MT-5111 is a 55 kD ETB targeting HER2 in solid tumors that binds to an epitope distinct from trastuzumab and pertuzumab, offering potential combination strategies with other HER2-targeting agents. MT-5111 was well tolerated with no clinically significant immuno- or cardiotoxicity. Dose escalation is ongoing and nearing levels expected to be required for efficacious exposure.

MT‑5111, a de-immunized 55 kD ETB targeting HER2 in solid tumors, also binds to an epitope distinct from trastuzumab and pertuzumab, which may permit combination strategies with other HER2 targeting agents. MT-5111 was well tolerated with no clinically significant cardiotoxicity. Continued dose escalations are ongoing.

MT-5111 binds an epitope on HER2, distinct from trastuzumab or pertuzumab, that may provide for combination potential with other HER2-targeting agents. Pts with evaluable disease may be included in Part 1; in Part 2, all pts must have =1 measurable lesion per Response Evaluation Criteria in Solid Tumors v1.1. Enrollment, which began in September 2019, is ongoing.