Based on genetic incidence rates, there are an estimated 27,000 patients with classic CAH and over 11,000 patients with Cushing’s disease in the United States. Of the patients with CAH and Cushing’s disease, we estimate that 17,000 and 5,000 patients, respectively, are potential candidates for treatment with atumelnant.
We conducted a double-blind, randomized, placebo-controlled Phase 1 study of atumelnant in healthy volunteers to assess the safety and tolerability of single and multiple doses of atumelnant. In addition, the study was designed to measure the effect of atumelnant on suppression of cortisol, cortisol precursors, and adrenal androgens following exogenous ACTH stimulation. In May 2022, we announced positive topline data from the Phase 1 study which showed atumelnant was well tolerated and demonstrated dose-dependent increases in atumelnant plasma concentrations. We believe atumelnant demonstrated pharmacologic proof-of-concept, as the Phase 1 results showed dose-dependent reductions of both basal cortisol and elevated cortisol following an ACTH challenge. All adverse events were considered mild to moderate and there were no serious adverse events.
We are conducting a Phase 2 study of atumelnant in CAH patients. This open-label study is designed to evaluate the safety, efficacy, and pharmacokinetics of different doses of atumelnant. In addition, biomarkers, including serum androstenedione and 17 hydroxyprogesterone, will be measured as we seek to evaluate the potential efficacy of atumelnant. We reported positive initial findings from our ongoing Phase 2 study in June 2024 (See “—Recent Developments”).
We are also conducting a clinical trial of atumelnant in patients with Cushing’s disease. We entered into a Clinical Trial Agreement with the National Institute of Diabetes and Digestive and Kidney Diseases (“NIDDK”) of the National Institutes of Health (“NIH”) to collaborate on a company-sponsored multiple-ascending dose trial of atumelnant in ACTH dependent Cushing’s Syndrome (“ADCS”). ADCS includes patients with either Cushing’s disease or Ectopic ACTH Syndrome (“EAS”). This open-label study is designed to evaluate safety, tolerability, and pharmacokinetics of different doses of atumelnant in patients with ADCS as well as to measure 24-hour urinary-free cortisol and serum cortisol as indicators of efficacy. We reported positive initial findings from our ongoing open-label Phase 1b/2a study in June 2024 (See “—Recent Developments”).
Parathyroid Hormone Antagonist
We are developing antagonists of the parathyroid hormone (“PTH”) receptor for the treatment of primary hyperparathyroidism (“PHPT”) and humoral hypercalcemia of malignancy (“HHM”) and other diseases of excess PTH. PTH regulates calcium and phosphate homeostasis in bone and kidney through activation of its receptor, PTHR1. Increased activation of PTHR1, either via PTH or PTH-related peptide (PTHrP, PTHLH) can lead to skeletal, renal, gastrointestinal, and neurological problems. Primary hyperparathyroidism arises from a small, benign tumor on one or more of the parathyroid glands, which results in over-secretion of PTH, leading to increased blood calcium levels (“hypercalcemia”). Some patients experience no symptoms, and many can have surgery to remove the tumor and/or hyperactive gland(s), while some require management with medical therapy. Symptomatic PHPT is characterized by skeletal, renal, gastrointestinal, and neurological manifestations with increased mortality. HHM typically arises in patients with advanced-stage cancers. In cases of HHM, over-secretion of PTHrP caused by the malignant tumor results in bone resorption and calcium reabsorption in the kidney, leading to hypercalcemia. We have identified investigational, orally available nonpeptide PTH antagonists that showed activity and drug-like properties in preclinical models. We have selected a development candidate to progress into first-in-human enabling activities in advance of commencing clinical trials.
SST3 Agonist Program for the Treatment for Autosomal Dominant Polycystic Kidney Disease
We have identified investigational, orally available somatostatin receptor type 3 (“SST3”) targeted nonpeptide agonists for the treatment of Autosomal Dominant Polycystic Kidney Disease (“ADPKD”). ADPKD, which is the most frequent genetic cause of chronic kidney disease, affecting 1 in 1,000 individuals, and is the fourth leading cause of end-stage renal disease. Cyst formation in renal tubules results from mutations in either the PKD1 or PKD2 genes. Over time, these developing cysts destroy the kidney architecture and impair kidney
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