Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) today announced that it earned a $30 million milestone payment from GSK (LSE/NYSE: GSK) following the start of GSK’s Phase 2b trial of GSK4532990, formerly called ARO-HSD, an investigational RNA interference (RNAi) therapeutic for the treatment of patients with non-alcoholic steatohepatitis (NASH).

GSK4532990 is being developed under the November 2021 exclusive license agreement between Arrowhead and GSK. GSK received an exclusive license to develop and commercialize GSK4532990 in all territories except Greater China, which was retained by Arrowhead. GSK is wholly responsible for further clinical development and commercialization, outside of Greater China.

GSK4532990 targets HSD17B13, a member of the hydroxysteroid dehydrogenase family involved in the metabolism of hormones, fatty acids, and bile acids. Published human genetic data indicate that a loss of function mutation in HSD17B13 provides strong protection against alcoholic hepatitis, cirrhosis, and NASH, with approximately 30-50% risk reduction compared to non-carriers.1

The double-blind, placebo-controlled Phase 2b HORIZON trial (NCT05583344) will evaluate the efficacy and safety of GSK4532990 in adults with pre-cirrhotic NASH. It will enroll up to 246 participants.

About Arrowhead Pharmaceuticals

Arrowhead Pharmaceuticals develops medicines that treat intractable diseases by silencing the genes that cause them. Using a broad portfolio of RNA chemistries and efficient modes of delivery, Arrowhead therapies trigger the RNA interference mechanism to induce rapid, deep, and durable knockdown of target genes. RNA interference, or RNAi, is a mechanism present in living cells that inhibits the expression of a specific gene, thereby affecting the production of a specific protein. Arrowhead’s RNAi-based therapeutics leverage this natural pathway of gene silencing.

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