Sonnet BioTherapeutics announced positive safety results for SON-1010, an IL-12 based immunotherapy, combined with atezolizumab in a Phase 1b/2a trial for advanced solid tumors and platinum-resistant ovarian cancer (PROC). The maximum tolerated dose (MTD) of SON-1010 was determined to be 1200 ng/kg, with no dose-limiting toxicities or cytokine release syndrome observed. Early signs of efficacy were observed, including one partial response in a PROC patient and stable disease in a significant portion of evaluable patients.
This positive safety profile at the MTD is crucial for the continued development of SON-1010, particularly given the historical safety concerns associated with rhIL-12. Demonstrating a manageable safety profile alongside preliminary signs of efficacy in a difficult-to-treat cancer like PROC opens the door for further clinical investigation and potential partnerships. This is particularly important for PROC patients who often have limited treatment options and low response rates to existing therapies, including checkpoint inhibitors. The observed partial response at the MTD, coupled with stable disease observed in other patients, suggests that SON-1010 in combination with atezolizumab could offer a new therapeutic approach for these patients.
The Phase 1b portion of the SB221 study successfully established the MTD for the combination therapy. Of the 15 evaluable patients, 33% exhibited stable disease at four months, with several continuing beyond six months. One PROC patient dosed at the MTD experienced a partial response with a 44% tumor reduction and a significant decrease in the CA 125 biomarker. Notably, the safety profile was favorable, with mostly mild and transient adverse events.
These results pave the way for the expansion phase of the SB221 trial, which will further investigate the combination therapy’s efficacy at the MTD in PROC patients before moving to a randomized Phase 2a comparison against the standard of care. The positive safety data and early efficacy signals position SON-1010 as a potential new treatment option for PROC and other solid tumors, warranting continued clinical investigation and potential partnerships to advance its development.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
