Aptose Biosciences Inc. provided a recent update from an ongoing APTIVATE Phase 1/2 clinical trial with the Company's lead agent, tuspetinib, a once daily oral agent with a unique kinase targeting pattern being developed for the treatment of patients with relapsed/refractory (R/R) AML. As of August 1, 2023, fifteen (15) patients had been dosed with the tuspetinib/venetoclax (TUS/VEN) doublet, ten (10) had reached an efficacy evaluable stage, and five (5) of the ten evaluable patients had achieved early responses (composite Complete Response rate (CRc) includes any CR, CRh, CRi and CRp). Among the ten (10) evaluable patients, nine (9) had failed prior venetoclax treatment (Prior-VEN), representing an emerging population with severe unmet medical need.

Four (4) of the nine (9) Prior-VEN failure patients had already achieved responses with TUS/VEN (44% CRc). Three (3) responses emerged among seven (7) of the evaluable patients with wildtype FLT3 (43% CRc), which accounts for approximately 70% of the AML population, yet there are few treatment options and little in development for the wildtype patient population. Additionally, two (2) of three (3) patients with mutated FLT3 (67%) achieved responses.

Importantly, The TUS/VEN combination continues to be safe and well tolerated.