Shattuck Labs' SL-172154 Gets FDA Orphan Drug Status for AML Treatment

In a significant development, Shattuck Labs, Inc. (Nasdaq: STTK), a clinical-stage biotechnology firm specializing in bifunctional fusion proteins, announced that the U.S. Food and Drug Administration (FDA) has granted orphan drug designation (ODD) to its leading clinical candidate, SL-172154, for treating Acute Myeloid Leukemia (AML). This designation underscores the urgent need for innovative treatments for AML, which currently offers limited therapeutic options and carries a dire prognosis for patients.

Taylor Schreiber, M.D., Ph.D., Chief Executive Officer of Shattuck, emphasized the importance of this milestone. “The FDA’s decision to grant ODD to SL-172154 highlights the critical necessity for novel treatment options for AML patients. This is a pivotal first step toward advancing to later-stage clinical trials.”

The FDA’s Office of Orphan Products Development awards orphan status to drugs aimed at treating, diagnosing, or preventing rare conditions affecting fewer than 200,000 individuals in the U.S. Drugs with this designation can benefit from a variety of incentives designed to support their development, including potential market exclusivity for seven years post-approval, eligibility for tax credits on qualified clinical trials, and exemption from FDA application fees.

Acute Myeloid Leukemia (AML) is a severe hematologic cancer that originates from the clonal expansion of myeloid precursors in the bone marrow. These leukemic blasts invade the bone marrow, disrupting normal blood cell formation. The National Cancer Institute's Surveillance, Epidemiology, and End Results Program reported approximately 20,380 new AML cases in the U.S. in 2023, with the disease resulting in around 11,310 deaths. The median age of diagnosis is 68, and a significant proportion of patients diagnosed are over 75 years old. The prognosis for older patients is particularly grim, with over 70% of those aged 65 and above succumbing to the disease within a year of diagnosis. As of 2019, the five-year relative survival rate for AML stood at about 32%.

SL-172154 (SIRPα-Fc-CD40L) is an experimental ARC® fusion protein designed to both inhibit the CD47/SIRPα checkpoint interaction and activate the CD40 costimulatory receptor, aiming to enhance the anti-tumor immune response in advanced cancer patients. Currently, multiple Phase 1 clinical trials are underway. These include studies involving patients with platinum-resistant ovarian cancer and individuals with AML and high-risk myelodysplastic syndromes (HR-MDS).

Shattuck Labs, Inc. is at the forefront of developing innovative bi-functional fusion proteins, a new class of biologic medicine targeting cancer and autoimmune diseases. Derived from Shattuck’s proprietary Agonist Redirected Checkpoint (ARC®) platform, these compounds are designed to simultaneously inhibit checkpoint molecules and activate costimulatory molecules with a single therapeutic agent. The company’s lead program, SL-172154, is being evaluated in multiple Phase 1 trials and focuses on blocking the CD47 immune checkpoint while activating the CD40 pathway. Shattuck Labs operates out of offices in Austin, Texas, and Durham, North Carolina.