Boundless Bio Announces Portfolio Prioritization and Runway Extension

Core Insights - Boundless Bio is focusing on the novel combination therapy of BBI-355 and BBI-825, along with the new development candidate BBI-940 for its kinesin program, aiming to optimize its portfolio for patient impact and long-term value creation [1][3][11] - The company's operating runway has been extended into the first half of 2028, allowing for expected proof-of-concept clinical readouts for each program [1][3][9] BBI-355 and BBI-825 Programs - The company has decided to discontinue the current monotherapy and combination arms of BBI-355 in the POTENTIATE clinical trial due to its narrow therapeutic index and associated hematological toxicity [4][6] - BBI-825 was not advanced in the STARMAP clinical trial due to a lack of dose proportional pharmacokinetic exposure, but there is a strong rationale for combining BBI-355 and BBI-825 for synergistic anti-tumor activity without overlapping toxicity [5][6] - Plans are in place to evaluate the combination of BBI-355 and BBI-825 in the POTENTIATE clinical trial, targeting initiation in the second half of 2025 [6][7] Kinesin Program - BBI-940 has been declared as the development candidate for the novel kinesin program, targeting a previously undrugged kinesin involved in DNA segregation [8] - The company expects to submit an Investigational New Drug (IND) application for BBI-940 in the first half of 2026 and deliver initial proof-of-concept clinical data within its extended cash runway timeline [8][9] Operational Update - Boundless Bio has streamlined its operations, resulting in approximately a one-third reduction of its workforce, which is expected to extend its cash runway into the first half of 2028 [9][10] - As of March 31, 2025, the company reported cash, cash equivalents, and short-term investments totaling $138.3 million, which will support its operations through anticipated clinical proof-of-concept readouts [9]