Spruce Biosciences has reported positive data from a Phase IIa clinical trial of tildacerfont to treat patients with congenital adrenal hyperplasia (CAH).
Classic CAH is a rare genetic disease that affects the functioning of adrenal glands. The disorder is caused by a mutation in the gene encoding the 21-hydroxylase enzyme required to synthesise important adrenal hormones.
Tildacerfont is an investigational, oral, selective small-molecule antagonist of the corticotropin-releasing factor type-1 (CRF1) receptor.
Preclinical studies found that the drug inhibits CRF-stimulated receptor function and addresses excess production of androgens, (androstenedione [A4]), progestins (17-hydroxyprogesterone [17-OHP]) and adrenocorticotropic hormone (ACTH).
The 12-week, multi-centre, open-label study was conducted to assess the safety, efficacy and tolerability of a 400mg, once-daily dose of the drug in adults with classic CAH.
Efficacy was measured as the reduction in major disease biomarkers over time in patients who had increased baseline ACTH and adrenal hormones.
Data revealed a mean decrease from baseline of 74% for ACTH, 82% for 17-OHP and 55% for A4.
The company said that ACTH is the direct target of the drug and A4 is the key downstream biomarker for clinical management of CAH patients.
Maximum mean reductions in the trial were 84% for ACTH, 82% for 17-OHP and 79% for A4.
Results further showed that 60% of participants with increased, abnormal ACTH and 40% of those having raised A4 experienced normalisation by week 12.
Spruce Biosciences CEO Richard King said: “The magnitude of these reductions coupled with patients having been able to achieve normalisation after only 12 weeks of treatment suggests that tildacerfont may provide a first-in-class option for patients to better manage their disease by reducing their exposure to elevated androgens and, potentially, their lifelong steroid burden.”
The study did not show any new safety signals. The majority of adverse events were considered to be mild, single-event occurrences that were not associated with the study drug.