May. 23 at 10:20 PM
$BOLD Boundless Bio discontinuing BBI-355 and BBI-825 programs
Boundless Bio "provided business updates focused on optimizing the Company's portfolio for patient impact and long-term value-creation. Boundless has been investigating BBI-355, a novel, oral, selective CHK1 inhibitor designed to target replication stress in oncogene-amplified cancers in its ongoing Phase 1/2 POTENTIATE clinical trial. In the trial, which explored different dose levels and dosing regimens, BBI-355 has demonstrated a narrow therapeutic index with continuous every other day dosing (Q2D), resulting from hematological toxicity at or near doses associated with clinical activity.
The Company believes BBI-355's narrow therapeutic index makes it suboptimal for continued development as a single agent with continuous dosing. In addition, the combinations of BBI-355 with the EGFR inhibitor erlotinib, and with the FGFR inhibitor futibatinib, were not well-tolerated with Q2D dosing at the exposure levels believed to be required for robust, sustained anti-tumor activity. Based on these findings and market considerations, the Company has decided to discontinue further clinical development in the current arms of the POTENTIATE clinical trial.
Boundless's novel Kinesin program targets a previously undrugged kinesin involved in DNA segregation, including ecDNA segregation, during mitosis. The Company has discovered orally bioavailable, highly selective Kinesin degraders that have demonstrated potent anti-tumor activity in a range of cancer cell lines as well as single agent tumor regressions in mouse xenograft cancer models. The Company selected BBI-940 as its development candidate and reaffirmed that it expects to submit an Investigational New Drug (IND) application in the first half of 2026.
Boundless expects to deliver initial proof-of-concept clinical data from BBI-940 within its extended cash runway timeline. In connection with its portfolio prioritization, Boundless has streamlined its operations, resulting in an approximately one-third reduction of its workforce. The Company believes the combination of portfolio prioritization, streamlined operations, and its cash, cash equivalents, and short-term investments of
$138.3 million as of March 31, 2025, will extend its operating runway into the first half of 2028 and through anticipated clinical proof-of-concept readouts for each of its therapeutic programs."
