The US Food and Drug Administration (FDA) has granted a fast track designation to Sellas Life Sciences Group’s SLS009 for the treatment of relapsed or refractory peripheral T-cell lymphomas (PTCL).
SLS009, formerly known as GFH009, is a potent CDK9 inhibitor designed to selectively block CDK enzyme activity, thereby shutting down cancer cell proliferation without destroying the immune system’s neutrophils.
The designation was based on results from the completed Phase I portion of the Phase I/IIa (NCT04588922) clinical study, an open-label, multi-centre, dose escalation and expansion study evaluating SLS009 as a treatment for relapsed and/or refractory hematological malignancies.
The study investigated SLS009 as a monotherapy in two dose escalation groups. Group one treated patients with relapsed/refractory acute myeloid leukaemia (AML) while group two studied patients with relapsed/refractory lymphomas, chronic lymphocytic leukaemia (CLL), and small lymphocytic lymphoma (SLL).
As per the company, results from the completed portion of the Phase I/IIa trial showed that four out of 11 PTCL patients treated with SLS009 monotherapy exhibited clinical responses. The Sellas announcement noted that the patient population in the Phase I/IIa SLS009 study was similar to that in Spectrum Pharmaceuticals’ Phase II study for Beleodaq (belinostat), an FDA-approved treatment for r/r PTCL.
Earlier this month, data from treatment group one allowed Sellas to secure an FDA orphan drug designation for SLS009 as a therapy for AML, and in September 2023, the company announced that all primary and secondary endpoints for treatment group two were met. As per an earlier update in April, SLS009 was safe and tolerated at all dose levels.
A third treatment group is evaluating the safety, tolerability, and antitumor activity of SLS009/ /azacytidine in combination with AbbVie/Genentech’s Venclexta (venetoclax) as a treatment for AML patients who have relapsed or are on refractory to Venclexta-based treatment plans.
The study’s expected completion date is in June 2024.
With the fast track designation, the development of SLS009 will be expedited, and if supported by clinical data, will become eligible for priority review and accelerated approval.
There is an urgent, unmet need for safe and effective PTCL treatments, said Sellas CEO Angelos Stergiou. The safety and efficacy of once-a-week 100mg SLS009 as a r/r PTCL treatment is currently being evaluated in the Phase I/IIb (NCT05934513) clinical trial conducted in China.
Completion of the trial is expected in June 2026.
Update: Paragraph 5 was updated to reflect the correct Phase I/IIa SLS009 study characteristics. A previous version incorrectly stated the response rate in the study was similar to that in a Phase II Beleodaq study.
