Abcuro Completes Enrollment of Sentinel Cohort in Phase 2/3 Study of ABC008 for the Treatment of Inclusion Body Myositis

Company expects to have a Data Safety and Monitoring Board (DSMB) review by the end of this year

NEWTON, Mass.–(BUSINESS WIRE)–Abcuro, Inc., a clinical-stage biotechnology company developing therapies for the treatment of autoimmune diseases and cancer through precise modulation of cytotoxic T and NK cells, today announced completion of enrollment of the sentinel cohort of a Phase 2/3 study of ABC008 for the treatment of inclusion body myositis (IBM). The company also announced that they expect to have review of the sentinel cohort safety data by an independent Data Safety Monitoring Board (DSMB) by the end of this year. The Phase 2/3 study is designed as a randomized, double-blind, placebo-controlled multicenter study. Upon favorable review by the DSMB, the study will progress with the main purpose of evaluating the efficacy, safety, and tolerability of two dose levels of ABC008 compared with placebo in subjects with IBM.

ABC008 is a first-in-class anti-KLRG1 antibody capable of selectively depleting highly cytotoxic T cells, which attack and destroy muscle tissue in IBM without affecting protective T cell populations. IBM is an autoimmune disease in which highly cytotoxic T cells chronically attack muscle tissue causing patients to progressively lose muscle function, including loss of grip, dexterity, and mobility. Muscle tissue from patients with IBM shows the presence of these T cells destroying muscle fibers.

“By completing enrollment of the sentinel group in the Phase 2/3 trial of ABC008 in IBM, we mark another important milestone in the progress of this potential first-in-class therapeutic for IBM patients,” said H. Jeffrey Wilkins, M.D., Chief Medical Officer of Abcuro. “We look forward to DSMB review later this year and the ongoing clinical evaluation of ABC008.”

In the Phase 1 trial of ABC008 in IBM subjects, an open label safety and tolerability study evaluating several dose levels both as single and repeat doses of ABC008, potent, durable, and dose-dependent depletion of CD8+KLRG1+ T cells, the most highly cytotoxic T cells, has been observed. At the dose levels being used in the Phase 2/3 trial, near complete depletion of blood target cells was observed with a single dose and persisted with repeat dosing in the Phase 1 trial.

“ABC008 was specifically designed with the potential to help patients with IBM, who are in great need for a treatment that can favorably alter the progressive disability IBM causes,” said Steven A. Greenberg, M.D., co-founder of Abcuro and Chief Scientific Advisor. “The selectivity of ABC008 offers a distinct advantage over broad T cell depleters for the potential treatment of autoimmune conditions like IBM. By targeting immune cells expressing KLRG1, key lymphocyte populations are spared, including naïve, memory and regulatory T cells which are required to maintain normal immune system homeostasis.”

About ABC008

ABC008 is a first-in-class anti-KLRG1 antibody capable of selectively depleting highly cytotoxic T cells, while sparing naïve, regulatory and central memory T cells. ABC008 has been designed to treat diseases mediated by highly cytotoxic T cells, including the autoimmune muscle disease inclusion body myositis (IBM), T cell large granular lymphocytic leukemia (T-LGLL), and mature T cell malignancies. The US Food and Drug Administration (FDA) has granted Orphan Drug Designation to ABC008 for the treatment of IBM.

About ABC008 Phase 2/3 Study

The ABC008 Phase 2/3 study is a randomized, double-blind, placebo-controlled, parallel multicenter study with three parts. The registrational Phase 2/3 trial will enroll more than 200 patients across 30 global sites. Part A involves enrollment of a sentinel safety cohort in which subjects will undergo safety and tolerability review by a DSMB after 20 weeks of treatment. With a favorable DSMB review, the study will progress to Part B, with the main purpose of evaluating the efficacy, safety, and tolerability of two dose levels of ABC008 (0.5 mg/kg and 2.0 mg/kg) compared with placebo at 76 weeks in subjects with IBM. Part C will provide pharmacodynamic follow-up for subjects who discontinue treatment. Additional details about the trial are available at ClinicalTrials.gov (NCT05721573).

About Abcuro

Abcuro is a clinical stage biotechnology company developing first-in-class immunotherapies for the treatment of autoimmune diseases and cancer through precise modulation of highly cytotoxic T and NK cells. The company’s lead program is ABC008 and is currently in clinical trials for inclusion body myositis (IBM) and T cell large granular lymphocytic leukemia. For more information, visit us on LinkedIn and at abcuro.com.

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Christine Quern
CBQ Communications

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