Two IPOs Raise $147 Million to Advance Rare Disease Therapies

Two biotech companies completed initial public offerings in mid-July raising a combined $147 million to advance their pipelines of rare disease therapeutics.

Foster City, California-based Mirum Pharmaceuticals priced its initial public offering of five million shares at $15 a share, the mid-point of its offer range, to raise $75 million. In the company’s registration statement, its current investors had indicated that they were planning to buy $35 million of the offering. Shares began trading on the Nasdaq Global Market under the symbol “MIRM”. 

Mirum is focused on developing and commercializing novel therapies for serious, rare liver diseases. The company’s lead drug maralixabat, is an investigational oral drug in late-stage development for progressive familial intrahepatic cholestasis (PFIC) and Alagille syndrome (ALGS). Both of these cholestatic diseases are due to genetic mutations and involve an interruption in the flow of bile acid from the liver, which results in excess bile acid in the liver and systemically. This leads to liver disease and a variety of severe and life-altering symptoms, including stunted growth and chronic and severe itch. Maralixibat works by inhibiting an important carrier protein known as the apical sodium dependent bile acid transporter (ASBT), thereby reducing systemic levels of bile acids.

Cambridge, Massachusetts-based Fulcrum Therapeutics priced its initial public offering of 4.5 million shares at $16 a share, at the lower end of its offer range, to raise $72 million. Its stock began trading on the Nasdaq Global Market under the ticker symbol “FULC”.

Fulcrum is focused on modulating gene expression to treat the root cause of genetically defined disease, with an initial focus on rare diseases of high unmet need. The company is currently testing its lead candidate losmapimod in a phase 1 trial to treat Landouzy-Dejerine Muscular Dystrophy, or FSHD, a rare, progressive and disabling disease characterized by progressive skeletal muscle loss that initially causes weakness in muscles in the face, shoulders, arms, and trunk, and continues to weakness throughout the lower body.

FSHD is caused by abnormal expression of DUX4 in skeletal muscle, which is normally silenced after early embryonic development. In patients with FSHD, the DUX4 gene is unsilenced as a result of a genetic mutation, leading to death of muscle and its replacement by fat. Losmapimod down regulates DUX4. Fulcrum’s pipeline also includes preclinical therapies targeting sickle cell anemia and beta thalassemia.