EMA Grants Orphan Drug Designation to SLS009 for R/R PTCL

Angelos Stergiou, MD, ScD

The European Medicines Agency (EMA) has granted orphan drug designation to the novel and highly selection selective CDK9 inhibitor SLS009 (formerly GFH009) as a potential therapeutic option for patients with relapsed/refractory peripheral T-cell lymphoma (PTCL).¹

“We are pleased to announce the EMA’s granting of orphan drug designation for SLS009, highlighting another important milestone following recent FDA’s orphan drug and fast track designations for SLS009 in PTCL,” Angelos Stergiou, MD, ScD hc, president and chief executive officer of SELLAS Life Sciences Group, stated in a news release. “PTCL is an aggressive form of lymphoma with limited treatment options, underscoring the urgent need for new and effective therapies.

“We are delighted that the potential of SLS009 has been recognized by both regulatory agencies and across multiple indications including acute myeloid leukemia [AML], pediatric AML, and pediatric acute lymphoblastic leukemia [ALL],” he added. “. This additional orphan drug designation also highlights our strong internal regulatory expertise, and we look forward to advancing the SLS009 development and our overall clinical programs to deliver its potential benefits to [patients with] cancer.”

Data from the dose-escalation portion of a phase 1/2 trial (NCT04588922) showed that SLS009 demonstrated safety and preliminary efficacy in patients with AML and lymphoma. Specifically inAmong patients with PTCL, the agent elicited an overall response rate (ORR) of 36.4%. One patient remained on continuous treatment for 56 weeks.

The ongoing study is enrolling patients at least 18 years of age and pediatric patients between 12 and 18 years of age with a body mass of at least 40 kg who have cytologically or histologically confirmed relapsed/refractory hematologic malignancies, including AML, chronic lymphocytic leukemia, small lymphocytic lymphoma, and lymphoma. Patients with lymphoma are required to have at least 1 measurable or evaluable lesion per 2014 Lugano response criteria, and exposure to at least 2 prior lines of systemic therapytherapy are needed.²

The study is excluding patients with bulky disease of at least 10 cm requiring cytoreductive therapy; those with symptomatic central nervous system (CNS) metastases or primary lymphoma, such as primary CNS lymphoma, leptomeningeal disease, or spinal cord compression; and patients with severe cardiovascular disease within 6 months of enrollment.

In group 2, patients with CLL, SLL, or lymphoma received escalating doses of SLS009. All other cohorts included patients with relapsed/refractory AML.

The study’s primary end points are safety and the incidence of dose-limiting toxicities. Secondary end points include pharmacokinetics, ORR, duration of response, progression-free survival, and overall survival.

An ongoing phase 1/2 trial (NCT05934513) in China is also investigating SLS009 in patients between 18 and 75 years of age with histologically confirmed relapsed/refractory PTCL. At least 2 and nor more than 5 prior lines of therapy are required. Other key inclusion criteria include at least 1 radiographically measurable lesion per Lugano criteria, an ECOG performance status of 0 to 2; and a life expectancy of at least 12 weeks.³

Patients with cutaneous T-cell lymphoma are being excluded from the study. Other exclusion criteria include symptomatic CNS metastases, leptomeningeal disease, or spinal cord compression; severe hemophagocytic syndrome at screening; and prior exposure to any CDK9 inhibitor.

All patients are receiving SLS009 once per week in 21-day cycles.

In phase 1b, safety is servingserves as the primary end point. ORR is the primary end point in phase 2.

In July 2024, the EMA also awarded orphan drug designation to SLS009 for patients with AML.⁴

References

1. SELLAS receives EMA orphan drug designation for SLS009 for treatment of peripheral T-cell lymphomas. News release. SELLAS Life Sciences Group. August 6, 2024. Accessed August 6, 2024. https://ir.sellaslifesciences.com/news/News-Details/2024/SELLAS-Receives-EMA-Orphan-Drug-Designation-for-SLS009-for-Treatment-of-Peripheral-T-cell-Lymphomas/default.aspx
2. Study of SLS009 (formerly GFH009) a potent highly selective CDK9 inhibitor in patients with hematologic malignancies. ClinicalTrials.gov. Updated June 14, 2024. Accessed August 6, 2024. https://clinicaltrials.gov/study/NCT04588922
3. A study of GFH009 monotherapy in patients with relapsed or refractory peripheral T-cell lymphoma (PTCL). ClinicalTrials.gov. Updated February 23, 2024. Accessed August 6, 2024. https://clinicaltrials.gov/study/NCT05934513
4. SELLAS receives European Medicines Agency orphan drug designation for SLS009 for the treatment of acute myeloid leukemia. News release. SELLAS. July 8, 2024. Accessed August 6, 2024. https://ir.sellaslifesciences.com/news/News-Details/2024/SELLAS-Receives-European-Medicines-Agency-Orphan-Drug-Designation-for-SLS009-for-the-Treatment-of-Acute-Myeloid-Leukemia/default.aspx