Sellas Life announces data from lymphoma cohort from SLS009 Phase 1 trial

SELLAS Life Sciences announced positive topline data for the patient group with relapsed/refractory lymphomas from the Phase 1 dose-escalation trial of its CDK9 inhibitor, SLS009. All primary and secondary study objectives, including safety, clinical activity, pharmacokinetics (PK), and pharmacodynamics, were successfully achieved. The recommended Phase 2 Dose for lymphoma patients has been established at the highest dose level evaluated of 100 mg, administered as a once-weekly infusion. The maximum tolerated dose was not reached. A dose-limiting toxicity occurred in one out of five patients treated at the 100 mg dose level. Key findings from the study include: Efficacy: Among 34 evaluable r/r lymphoma patients, five achieved a clinical response with a reduction in tumor burden of up to 62%. An additional seven patients achieved stable disease resulting in an overall disease control rate of 35.3%. In the subgroup of PTCL patients, four out of 11 evaluable patients achieved a clinical response. Safety: There were no drug-related fatalities at any dose level, and the drug was well tolerated. In patients treated with the BIW regimen, no significant safety events appeared to be dose-dependent. In patients receiving the QW regimen, greater than or equal to G3 treatment-related adverse events occurred, primarily hematologic events, at higher dose levels. Non-hematologic toxicities were rare across all dose levels with five out of 52 patients experiencing higher grade toxicities, including hypokalemia, upper respiratory tract infection and increase in bilirubin. Maximum Tolerated Dose was not reached with only 1/5 patients at the highest dose level studied experiencing a dose-limiting toxicity. No dose-limiting toxicities were observed at any other dose level, and there were no unexpected toxicities across the study. Pharmacokinetic Data: Exposure parameters increased in an approximately proportional manner with the dose range of 30 mg~60 mg QW. The exposure of 100 mg was the highest, and the mean plasma concentration remained above IC90 for the longest time period. Pharmacodynamic Data: Desired levels of suppression in peripheral blood were achieved, leading to a decrease in MCL1 or MYC biomarkers in all studied patients. Biomarker suppression was dose-dependent in patients receiving QW dosing. The biomarkers studied included MYC and MCL1 with SLS009 administration resulted in biomarkers suppression across dose levels in both administration regimens and a dose-dependent decrease in QW groups. 100mg QW DL resulted in the longest sustained inhibition of both MCL1 and MYC.