Sparrow Pharmaceuticals announced positive phase 2a data for clofutriben, a selective 11β-hydroxysteroid dehydrogenase type 1 (HSD-1) inhibitor, demonstrating statistically significant improvements in HbA1c, glucose, and total cholesterol in adults with type 2 diabetes (T2D) at the 2026 American Diabetes Association (ADA) Scientific Session.1
According to Sparrow Pharmaceuticals, data derived from a 6-week, randomized, double-blind, placebo- and active-controlled phase 2 trial (NCT02372578), which was originally designed to evaluate clofutriben’s effects on neuropathic pain, showed meaningful glycemic and lipid improvements across 2 patient populations. The company noted particularly pronounced effects in a subset of participants with clinical features associated with elevated cortisol risk.
Frequently Asked Questions
What is clofutriben’s mechanism of action?
Clofutriben is a selective inhibitor of 11β-hydroxysteroid dehydrogenase type 1 (HSD-1), an enzyme responsible for generating intracellular cortisol in metabolically active tissues such as liver, adipose, and muscle. By reducing local cortisol levels, the drug aims to address cortisol-driven treatment resistance and cardiometabolic dysfunction independently of other antidiabetic mechanisms.
What is CAPTAIN-T2D and when are results expected?
CAPTAIN-T2D is an ongoing double-blind phase 2b trial enrolling patients with inadequately controlled T2D and confirmed elevated cortisol, with a 24-week primary endpoint of change in HbA1c. Full results timing has not been announced by Sparrow Pharmaceuticals.
“These Phase 2 data reinforce our conviction that clofutriben could play an important role in improving not only glycemic control but also broad cardiometabolic dysfunction,” said Robert Jacks, president and CEO of Sparrow Pharmaceuticals. “Clofutriben’s novel mechanism targets cortisol, an often-overlooked driver of treatment resistance and disease progression, providing the potential to be a therapeutic option for patients whose needs are not addressed by current therapies.”
Clofutriben efficacy in phase 2a: ITT and EC-enriched populations
In the intent-to-treat (ITT) population (N=75), treatment with clofutriben 10 mg once daily produced statistically significant placebo-adjusted reductions in HbA1c (−0.36%), glucose (−1.64 mM), and total cholesterol (−0.76 mM) after 6 weeks.1 These improvements were observed across a broadly defined T2D population, providing initial evidence of the drug’s glycemic and lipid-lowering activity.
A prespecified elevated cortisol (EC) risk factor-enriched subset — defined as patients with HbA1c ≥7.5% on 2 or more antidiabetic medications (N=25) — showed numerically larger placebo-adjusted improvements across all cardiometabolic parameters.1 In this subset, clofutriben produced reductions in HbA1c (−0.51%), glucose (−3.43 mM), total cholesterol (−1.17 mM), and triglycerides (−0.86 mM).1
Weight declined by 1.3 kg, with small reductions also observed in systolic blood pressure (−2.4 mmHg) and diastolic blood pressure (−1.3 mmHg).1 Sparrow noted the numerically greater effects in the EC-enriched subset as consistent with the drug’s proposed mechanism: reducing intracellular cortisol in metabolically active tissues, where elevated cortisol is thought to drive both treatment resistance and disease progression.
Clofutriben safety profile and CAPTAIN-T2D trial design
According to Sparrow Pharmaceuticals, no clinically significant safety signals were observed in clinical laboratory measurements, vital signs, or electrocardiogram results in the phase 2 trial. The majority of adverse events were mild or moderate in intensity.1 1 patient randomized to clofutriben experienced thrombocytopenia as a treatment-emergent serious adverse event and discontinued the trial; that patient had an undisclosed prior history of idiopathic thrombocytopenic purpura.1
Sparrow is currently conducting CAPTAIN-T2D, a double-blind phase 2b trial evaluating clofutriben in patients with inadequately controlled T2D and confirmed elevated cortisol.
The trial is structured in 2 parts: Part 1 screens patients with T2D and EC risk factors to confirm EC status, and Part 2 randomizes eligible participants to clofutriben or placebo in a dose-ranging intervention.1
The primary endpoint of CAPTAIN-T2D is change in HbA1c at 24 weeks, with exploratory endpoints covering body weight, blood pressure, cholesterol, and bone metabolism biomarkers.1
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