Benzinga | Jun 4, 2021 09:10AM EDT

Bolt Biotherapeutics Presents Preliminary Results from Phase 1/2 Trial of Lead HER2-targeting Boltbody ISAC BDC-1001 at ASCO 2021

Bolt Biotherapeutics, Inc. (NASDAQ:BOLT), a clinical-stage biotechnology company pioneering a new class of immuno-oncology agents that combine the targeting precision of antibodies with the power of both the innate and adaptive immune systems, today announced that a poster presentation discussing preliminary data from the Phase 1/2 clinical trial of BDC-1001, Bolt's lead candidate, was presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, being held virtually from June 4-8, 2021. The poster is titled "Preliminary results from a phase 1/2 study of BDC-1001, a novel HER2 targeting TLR7/8 immune-stimulating antibody conjugate (ISAC), in patients (pts) with advanced HER2-expressing solid tumors."

BDC-1001 is a human epidermal growth factor receptor 2, or HER2, ISAC comprised of a HER2-targeting biosimilar of trastuzumab conjugated to one of Bolt's proprietary TLR7/8 agonists, for the treatment of patients with HER2-expressing solid tumors, including HER2-low tumors. As of January 29, 2021, Bolt had treated 20 patients and BDC-1001 appeared to be well tolerated with mild to moderate adverse events; no dose-limiting toxicities or drug-related serious adverse events were observed. Clinical activity was seen in the form of stable disease, reductions in tumor volume including a confirmed partial response and increases in pharmacodynamic markers that Bolt believes are consistent with its proposed mechanism of action.

"This poster reinforces the favorable safety and tolerability demonstrated in the first 20 patients treated with BDC-1001 in this first-in-human study in patients with HER2-expressing cancers," said Manish R. Sharma, M.D., of START Midwest, a principal investigator in Bolt's ongoing BDC-1001 Phase 1/2 trial. "We have seen signs of activity, including a patient with a confirmed partial response and others with stable disease, in a population with diverse tumor types and a median of four prior lines of therapy."

The BDC-1001 Phase 1/2 trial is expected to enroll up to a total of 390 patients and is being conducted in four parts, with dose-escalation dose-expansion parts exploring both monotherapy and combination with a PD-1 checkpoint inhibitor. The monotherapy dose-escalation part of the trial continues to proceed according to plan, and full results are expected to be presented in the second half of 2021. Bolt plans to advance to the monotherapy Phase 2 dose-expansion cohorts and the dose-escalation combining BDC-1001 with an anti-PD-1 antibody later this year.

"I amgrateful to everyone on the team for their hard work throughout this trial, especially during the pandemic," said Ecaterina Dumbrava, M.D., of The University of Texas MD Anderson Cancer Center, a principal investigator of the BDC-1001 Phase 1/2 trial. "These initial data provide additional support for the ISAC targeted approach that stimulates both the innate and adaptive immune systems in the treatment of cancer patients."

The abstract and poster from the ASCO presentation can be found on the ASCO website, as well as on the Bolt website.