Arrowhead Pharmaceuticals Earns $200 Million Milestone Payment from Sarepta Therapeutics

Arrowhead Pharmaceuticals, Inc. (NASDAQ:ARWR) today announced that it has earned a $200 million milestone payment from Sarepta Therapeutics (NASDAQ:SRPT). The milestone was earned when Arrowhead achieved the second development milestone event in a Phase 1/2 clinical study of ARO-DM1, also called SRP-1003, an investigational RNA interference (RNAi) therapeutic for the treatment of type 1 myotonic dystrophy (DM1), the most common adult-onset muscular dystrophy. In accordance with the license and collaboration agreement with Sarepta, Arrowhead expects to receive this payment within 60 days.

The second milestone event was reached following a drug safety committee review, subsequent authorization to dose escalate, and achievement of a pre-specified patient enrollment target. Accrual of patients in cohort 4 (6 mg/kg) of the multiple ascending dose (MAD) portion of the study is nearly complete and the company intends to initiate enrollment in cohort 5 (12 mg/kg) in the first quarter of 2026.

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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Source: Arrowhead Pharmaceuticals, Inc.

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Arrowhead Pharmaceuticals, Inc.

Vince Anzalone, CFA

626-304-3400

[email protected]

Investors:

LifeSci Advisors, LLC

Brian Ritchie

212-915-2578

[email protected]

Media:

LifeSci Communications, LLC

Kendy Guarinoni, Ph.D.

724-910-9389

[email protected]