Bolt Biotherapeutics Reports Interim BDC-1001 Phase 1/2 Data Demonstrating a Safe and Well-tolerated Profile and Emerging Clinical Activity at the ESMO Immuno-Oncology Congress 2021 - Seite 2

• BDC-1001 continues to have a favorable safety and tolerability profile with mild (grade 1/grade 2) infusion related reactions in some patients and no dose-limiting toxicities at dose levels up to 20 mg/kg every three weeks and 12 mg/kg every two weeks. There was no indication of cytokine release syndrome (CRS), and a maximum tolerated dose (MTD) has not been reached.
• Early signs of clinical activity are noted in 13 of 40 tumor evaluable subjects with one durable partial response maintained through 52 weeks and multiple subjects achieving stable disease for >12 weeks.
• The pharmacokinetic (PK) data demonstrate increasing peak drug levels with increasing dose, and linearity of PK above the 5 mg/kg dose level. Clinical PK modeling predicts that target exposure levels can be achieved with weekly dosing.
• Plasma and tissue biomarker results show increase in multiple biomarkers indicative of myeloid cell and TLR 7/8 activation that is consistent with BDC-1001’s mechanism of action. Increasing drug exposure correlates with increases in plasma cytokines and corresponding biomarker changes in the tumor microenvironment of multiple post-treatment tumor biopsies, with intriguing signs of clinical disease control.

These encouraging data point to the need for increased drug exposure to optimize clinical benefit. The favorable safety profile of BDC-1001 allows for continued enrollment in the dose escalation portion of the study, and the Company’s refined PK model based on data from more than 50 patients predicts that weekly administration will provide BDC-1001 exposures at or above the target exposure threshold. The data also support initiation of the combination therapy study with nivolumab (PD-1 inhibitor).

“Bolt Biotherapeutics is committed to agile clinical development based on data. In this Phase 1/2 study of BDC-1001, we have gained tremendous insight into the ability of this novel candidate to mobilize the patient’s immune system in targeting the tumor and its microenvironment. The increases in myeloid cell infiltration and repolarization of macrophages we’ve seen in multiple post-treatment biopsies are provocative and consistent with our proposed mechanism of action,” said Edith Perez, M.D., Chief Medical Officer of Bolt Biotherapeutics. “We look forward to exploring weekly dosing as we get closer to determining the recommended Phase 2 dose for BDC-1001 as monotherapy, and to initiating combination therapy with a checkpoint inhibitor.”