AUSTIN, Texas, Dec. 09, 2019 (GLOBE NEWSWIRE) -- Molecular Templates, Inc., (NASDAQ:MTEM) a clinical-stage biopharmaceutical company focused on the discovery and development of the Company's proprietary engineered toxin bodies (ETBs), which are differentiated, targeted, biologic therapeutics, today announced the presentations of two posters on its pipeline programs at the American Society of Hematology (ASH) 2019 Annual Meeting, taking place December 7-10, 2019 in Orlando, Florida. One of these posters includes final results from the Phase 1/1b study of MT-3724, in subjects with relapsed/refractory (R/R) diffuse large b-cell lymphoma (DLBCL).
| Poster Title: | Monotherapy Activity with the First CD20-Targeted Immunotoxin, MT-3724, in Subjects with Relapsed/Refractory (R/R) Diffuse Large B-Cell Lymphoma (DLBCL) |
| Abstract Number: | 4098 |
| Presenter: | Daniel Persky MD, University of Arizona Cancer Center |
| Session: | 626. Aggressive Lymphoma (Diffuse Large B-Cell and Other Aggressive B-Cell Non-Hodgkin Lymphomas)—Results from Prospective Clinical Trials |
| Time: | Monday, December 9, 2019: 6:00 PM-8:00 PM ET |
This is a multi-center, open-label, dose-escalation and dose-expansion study of MT-3724, the first CD20 targeted immunotoxin to enter clinical trials. The Phase 1/1b portion of the study consists of two Parts in which a total of 27 subjects with NHL were enrolled; 21 in Part 1 (dose escalation) and 6 in Part 2 (expansion cohort), both closed to enrollment. In total, 25 subjects were evaluable for efficacy, including 19 subjects with DLBCL or mixed DLBCL/follicular lymphoma.
MT-3724 competes for binding with rituximab (RTX) and other commercially available CD20-targeting monoclonal antibodies. Consistent with this competition, initial efficacy data from the dose expansion study revealed only one of eight subjects with measurable serum rituximab (RTX) levels had any suggestion of benefit (a mixed response) to MT-3724.
The expansion cohort mandated negative serum RTX levels for enrolled subjects. Of the 13 serum rituximab negative (RTX-neg) DLBCL or mixed DLBCL/FL subjects, 5 responded (38% objective response rate) across the range of 5 to 100 μg/kg doses. Of the 5 responses, 2 were complete responses (CRs) and 3 were partial responses (PRs). Three patients had stable disease (including 2 patients with 49% and 47% tumor reductions) and 5 patients had progressive disease.
Of the 5 serum RTX-neg subjects with DLBCL who received MT-3724 at 50 μg/kg, the maximum tolerated dose (MTD), 3 responded (2 CR, 1 PRs). Of all 25 subjects evaluable for efficacy, 13 developed anti-drug antibodies (ADAs) or neutralizing antibodies (NAbs); the development of ADAs or NAbs did not preclude benefit of MT-3724, consistent with what has been seen with other immunotoxins. Safety events were mostly mild to moderate, and dose limiting toxicities (DLTs) were indicative of innate immune response, including grade 2 capillary leak syndrome and grades 1-3 arthralgias and myalgias. No life-threatening toxicities were attributed to MT-3724.
A Phase 2 dose-expansion portion of the study (Part 3) has been initiated to investigate MT-3724 in serum RTX-neg subjects with DLBCL. This is actively enrolling globally. A tolerable dose and schedule for the Phase 2 has been identified: 50 μg/kg/dose with a cap of 6000 μg/dose infused over 1 hour on Days 1, 3, 5, 8, 10 and 12 of a 21-day cycle. (ClinicalTrials.gov Identifier: NCT02361346).
The study is currently ongoing; eligible subjects will be identified and treated through competitive enrollment at multiple study centers (ClinicalTrials.gov Identifier: NCT03645395).
Copies of the posters presented at ASH can be found in the Presentations section of Molecular Templates' website at http://ir.mtem.com/events-and-presentations/presentations.
Investor Contact:
Adam Cutler
Chief Financial Officer
[email protected]
862-204-4006
Source: Molecular Templates, Inc.
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