Spruce Biosciences Raises $88 Million to Advance Rare Endocrine Disease Pipeline

Rare Daily Staff

Spruce Biosciences completed an $88 million series B financing round to support late-stage development of the biotech’s lead compound, tildacerfont, a treatment for classic congenital adrenal hyperplasia and other rare endocrine disorders.

Omega Funds and Abingworth led the round with participation by existing investors Novo Holdings and RiverVest Venture Partners. New investors HealthCap Partners, Rock Springs Capital, Surveyor Capital, Aisling Capital, and Sands Capital also participated in the round.

Classic congenital adrenal hyperplasia (CAH) is a rare genetic disorder that affects the proper functioning of the adrenal glands. CAH results from a mutation in the gene that encodes the enzyme 21-hydroxylase, which is necessary for the synthesis of key adrenal hormones. As a result, people with CAH have an impaired ability to produce the hormone cortisol, which can result in life-threatening adrenal crises. Cortisol is also known as “the stress hormone,” and is critical for the body’s response to stress, illness and injury.

In CAH, the adrenal glands also often produce excessive levels of male sex hormones or androgens. While both sexes need androgens for proper growth and development, an excess can cause problems that may include precocious puberty, short stature, hirsutism, increased risk of testicular adrenal rest tumors in men, and virilization and menstrual dysfunction in women.

While CAH testing is part of the newborn screening program, treatment options are limited. Glucocorticoids are commonly used to treat CAH but are associated with a wide range of side effects, including weight gain, stunted growth in children, reduced bone mineral density, metabolic abnormalities and increased cardiovascular risk. No new treatment options for CAH have been approved for the past several decades.

Spruce’s tildacerfont is a second generation CRF-1 receptor antagonist and the first non-steroidal molecule to demonstrate an ability to normalize elevated androgens in patients with CAH in clinical studies. In September, Spruce reported results from a 12-week phase 2a study in adults with CAH that showed treatment with tildacerfont resulted in maximum mean reductions of up to 84 percent in adrenocorticotropic hormone, a key disease biomarker in CAH patients with elevated androgens, with the majority of treated patients seeing their ACTH levels normalize as a result of treatment. This may allow physicians to reduce the chronic, high-dose steroids used to treat CAH and improve control of the disease.

“In addition to addressing these unmet needs in CAH, tildacerfont’s mechanism of action could also be relevant in patients suffering other abnormalities of the hypothalamic-pituitary adrenal axis, including non-classic CAH, Cushing’s Disease, and polycystic ovary syndrome,”  said Wiebke Arlt, director of the Institute of Metabolism and Systems Research at the University of Birmingham, United Kingdom.

Tildacerfont has been granted orphan drug status by both the U.S. Food and Drug Administration and the European Medicines Agency.

“The potential utility of tildacerfont, as well as an interest in broader rare endocrine disorders, has attracted a strong group of investors,” said Richard King, president and CEO of Spruce Biosciences.

Photo: Richard King, president and CEO of Spruce Biosciences.