SELLAS Life Sciences Group, Inc. announced that the U.S. Food and Drug Administration (FDA) has granted Rare Pediatric Disease Designation (RPDD) to SLS009, a highly selective CDK9 inhibitor, for the treatment of pediatric acute lymphoblastic leukemia (ALL). Childhood ALL is a life-threatening disease with a high unmet medical need. Despite significant advances in the treatment of pediatric ALL, relapse continues to be the most common cause of treatment failure.

There are patient subpopulations with high-risk and very high-risk features in need of less toxic therapies that would ultimately extend their long-term event-free survival (EFS) which remains around 50% for very high-risk groups. In clinical trials, SLS009 has demonstrated a very favorable safety profile with complete absence, to date, of any non-hematologic clinical higher-grade toxicities. Rare Pediatric Disease (RPD) Designation is granted by the FDA for serious or life-threatening diseases that affect fewer than 200,000 people in the United States, and in which the serious or life-threatening diseases primarily affect individuals less than 18 years of age.

If, in the future, a New Drug Application (NDA) for SLS009 for the treatment of pediatric AML is approved by the FDA, SELLAS might be eligible to receive a Priority Review Voucher (PRV) that could be redeemed to receive a priority review for any subsequent marketing application. PRVs may be used by the sponsor or sold to another sponsor for their use and have recently sold for approximately $100 million.