10:33 AM
Nov 07, 2018
 |  BC Extra  |  Financial News

Mirum launches with liver disease candidates from Shire

Mirum Pharmaceuticals Inc. (San Francisco, Calif.) launched with a $120 million series A round and a license from Shire plc (LSE:SHP; NASDAQ:SHPG) to a pair of candidates to treat liver diseases. The start-up intends to start Phase III testing next year of one compound, maralixibat (formerly SHP-625), to treat Alagille syndrome and progressive familial intrahepatic cholestasis (PFIC).

New Enterprise Associates led the round. Also participating were Deerfield Management, Frazier Healthcare Partners, Novo Holdings A/S (Hellerup, Denmark), Pappas Capital, RiverVest Venture Partners and Rock Springs Capital.

Both of Mirum's lead candidates are inhibitors of solute carrier family 10 sodium-dependent bile acid transporter member 2 (SLC10A2; ASBT; IBAT). Marilixibat is in Phase II testing to treat cholestatic liver diseases. In July, Shire disclosed that it stopped a Phase II trial of the other, volixibat (SHP626), based on efficacy findings to treat non-alcoholic steatohepatitis (NASH).

Shire acquired both compounds via its takeout of Lumena Pharmaceuticals Inc. in 2014 for $260 million up front. Mirum Chairman and CEO Mike Grey was Lumena's president and CEO; Mirum's staff includes several other members of Lumena's management team as well (see "Luminous ROI").

Under Shire, maralixibat missed the primary and secondary endpoints in the Phase II IMAGO trial evaluating the compound in pediatric patients with Alagille syndrome. But Mirum said an interim analysis of another study, the ongoing Phase IIb ICONIC trial in Alagille syndrome, showed maralixibat reduced bile acids and pruritus compared with placebo (see “Priority Review Erases Shire’s Losses on Trial Miss”).

Grey told BioCentury that the ICONIC trial included a higher dose than IMAGO -- a maximum dose of 400 μg/kg compared with IMAGO's maximum dose of 200 μg/kg -- and utilized a trial design that reduces the placebo effect by switching patients from the treatment group to the placebo group. Mirum plans to use both modifications in Phase III trials.

Mirum said the compound also led to reductions in bile acids and pruritus among a subset of patients with PFIC type 2 in a Phase II study. Maralixibat has breakthrough therapy designation from FDA to treat PFIC type 2, a form of the disease which typically leads to liver failure within the first few years of life.

The company plans to present detailed data next year from ICONIC and the PFIC study.

Mirum may evaluate volixibat in liver diseases other than NASH, Grey said.

Shire will receive an upfront payment and an equity stake in Mirum, and is eligible for milestones and royalties. Financial terms were not disclosed.

NEA's Ed Mathers, Frazier's Patrick Heron, Deerfield's Jonathan Leff, Novo's Tiba Aynechi and RiverVest's Niall O’Donnell will join the company’s board.

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