Sparrow Pharmaceuticals' clofutriben, a potent and selective HSD-1 inhibitor, has been granted Orphan Drug Designation by the FDA for the treatment of endogenous Cushing syndrome, also known as hypercortisolism. This rare endocrine disorder results from the body's overproduction of cortisol, often due to adrenal gland issues or tumors. The company also announced the completion of its Phase 2 RESCUE trial, which assessed clofutriben in patients with ACTH-dependent endogenous Cushing syndrome.
Novel Mechanism of Action
Clofutriben's mechanism of action targets HSD-1, an intracellular enzyme that activates glucocorticoids in target tissues. By inhibiting HSD-1, clofutriben aims to reduce cortisol activity specifically in tissues affected by the excess hormone, such as the liver, adipose tissue, brain, bone, muscle, and skin. This approach contrasts with existing therapies that often carry significant risks of adrenal insufficiency and adrenal crisis, according to Frank Czerwiec, MD, PhD, chief medical officer at Sparrow.
Clinical Trial Results and Future Plans
The randomized, placebo-controlled RESCUE trial focused on individuals with ACTH-dependent endogenous Cushing syndrome, a condition caused by tumors leading to cortisol hypersecretion. According to Sparrow Pharmaceuticals, patients in the trial showed a preference for continuing clofutriben treatment in an open-label extension, rather than switching to alternative therapies. "One of the most encouraging observations is that, given the option to continue clofutriben or switch to another treatment at the end of the trial, patients chose to continue clofutriben in the [open-label extension]," said Czerwiec.
Sparrow Pharmaceuticals is collaborating with medical, scientific, and patient advisors to present the RESCUE trial data and design subsequent clinical trials, planned to commence next year. Jamie MacPherson, PharmD, senior vice president of regulatory affairs and quality at Sparrow, stated, "We are pleased that the FDA has recognized the potential for clofutriben to treat this devastating disease."
Addressing Unmet Needs in Cushing Syndrome
Endogenous Cushing syndrome presents significant diagnostic challenges due to its slow development and diverse symptoms, including weight gain, diabetes, hypertension, osteoporosis, muscle loss, fragile skin, and cognitive changes. Current treatments often have limitations in safety, tolerability, and complexity. Clofutriben's novel approach aims to address these unmet needs by offering a more targeted therapy with potentially fewer side effects.
Clofutriben is also being explored for autonomous cortisol secretion, a milder form of hypercortisolism, and in combination with prednisolone for treating immunological disorders, highlighting its potential versatility.
