Sparrow Pharmaceuticals' Clofutriben Completes Phase 2 Trial and Receives FDA Orphan Drug Designation for Cushing's Syndrome
Key Insights
Sparrow Pharmaceuticals (search) has completed its Phase 2 RESCUE trial of clofutriben for ACTH-dependent endogenous Cushing’s syndrome (search), with all eligible patients continuing treatment in an open-label extension.
Clofutriben, a selective HSD-1 (search) inhibitor, offers a novel approach by lowering intracellular cortisol in key tissues, potentially mitigating the safety and tolerability issues of current therapies.
The FDA has granted Orphan Drug Designation to clofutriben for endogenous Cushing’s syndrome (search), providing incentives such as tax credits and potential market exclusivity.
Sparrow Pharmaceuticals (search) has announced the completion of its Phase 2 RESCUE trial evaluating clofutriben for the treatment of ACTH-dependent endogenous Cushing’s syndrome (search). The trial's promising results have led to plans for the next phase of development, slated to begin next year. Furthermore, the FDA has granted clofutriben Orphan Drug Designation for the same indication.
The RESCUE trial was a randomized, placebo-controlled study focusing on ACTH-dependent endogenous Cushing’s syndrome (search), a rare condition characterized by a tumor-induced hypersecretion of cortisol. Clofutriben, a selective HSD-1 (search) inhibitor, works by reducing intracellular cortisol levels in tissues affected by excess cortisol, potentially decreasing associated morbidity.
Novel Mechanism of Action
Frank Czerwiec, MD, PhD, Chief Medical Officer of Sparrow, highlighted the innovative approach of clofutriben: "HSD-1 (search) inhibition with clofutriben is a completely novel approach to the treatment of endogenous Cushing’s syndrome (search) that may overcome many of the serious problems with current therapies, including major safety, tolerability, and complexity issues such as the risk of adrenal insufficiency and adrenal crisis." He also noted the positive patient response, with all eligible patients choosing to continue clofutriben treatment in an open-label extension (OLE) protocol.
FDA Orphan Drug Designation
The FDA's Orphan Drug Designation (ODD) for clofutriben provides Sparrow Pharmaceuticals (search) with several benefits. Jamie MacPherson, PharmD, SVP of Regulatory Affairs and Quality at Sparrow, explained that the ODD qualifies sponsors for incentives including tax credits for qualified clinical trials, exemption from user fees, and a potential seven years of market exclusivity after NDA approval. "We are pleased that the FDA has recognized the potential for clofutriben to treat this devastating disease," MacPherson added.
Clofutriben's Broader Applications
Clofutriben is currently in clinical testing for both endogenous Cushing’s syndrome (search) (EnCS) and autonomous cortisol secretion (ACS). HSD-1 (search), the target of clofutriben, is an intracellular enzyme that activates glucocorticoids in tissues where cortisol excess contributes to morbidity, such as the liver, adipose tissue, brain, bone, muscle, and skin. Additionally, clofutriben is being investigated in combination with prednisolone for immunological disorders, starting with polymyalgia rheumatica (search) (PMR), aiming to reduce prednisolone's side effects while maintaining its anti-inflammatory benefits.