SELLAS Life Sciences announced positive Phase 2a trial data for SLS009 (tambiciclib), a CDK9 inhibitor, combined with Brukinsa (zanubrutinib) in relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL). The trial, conducted by GenFleet Therapeutics in China, showed a 67% overall response rate, significantly exceeding the anticipated response rate of zanubrutinib alone. This combination therapy also demonstrated a median overall survival that was not yet reached after a median follow-up of 4.6 months, with 67% of patients still alive.
This positive data is particularly encouraging for patients with non-GCB (ABC) DLBCL, a subtype associated with a poorer prognosis. The combination therapy demonstrated an 83% disease control rate in these patients, suggesting a potential new treatment avenue for this difficult-to-treat population. Moreover, the observed efficacy in patients without MYD88 or CD79B mutations, typically predictive of a better response to BTK inhibitors, suggests broader applicability of the SLS009/zanubrutinib combination. The complete response observed in a patient with both MYC amplification and TP53 mutation further highlights the potential of SLS009 to overcome drug resistance mechanisms in cancer.
Nine r/r DLBCL patients participated in the trial, six with the non-GCB subtype. One patient achieved complete response, and three achieved partial response with significant target lesion shrinkage. Grade 3 or higher adverse events were reported in 55.6% of patients, consistent with the expected safety profile of zanubrutinib monotherapy. While GenFleet will determine next steps for the lymphoma trial, SELLAS remains focused on acute myeloid leukemia and spliceosome-chromatin mutation related cancers.
These findings represent a potential advancement in DLBCL treatment, especially for the non-GCB subtype. The SLS009 and zanubrutinib combination may offer a more effective therapeutic approach, warranting further investigation. Although SELLAS is not directly pursuing the next steps in lymphoma, these results demonstrate the potential of SLS009 in a broader range of cancers and may attract partners interested in advancing the lymphoma program. This data could also inform future research into combination therapies incorporating CDK9 inhibition.
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.
