Roche snaps up ex-US rights to Sarepta's DMD gene therapy

Roche has bought ex-US rights to Sarepta’s Duchenne muscular dystrophy (DMD) gene therapy in a potential multi-billion dollar deal.

The big Swiss pharma will pay $750 million cash up front and $400 in equity under the deal, and will pay Sarepta up to $1.7 billion in regulatory and sales milestones, plus royalties on net sales.

US biotech Sarepta will continue to be responsible for clinical development and manufacturing of the drug SRP-9001, also known as (AAVrh74.MHCK7.micro-dystrophin),with global clinical development costs shared equally with Roche.

As part of the agreement, Roche also obtains an option to acquire ex-US rights to certain future DMD-specific programs from Sarepta, in exchange for separate milestone and royalty considerations, and cost sharing.

The gene therapy, which is being tested in a phase 1/2 trial, is based around a truncated version of the gene for the dystrophin protein that is deficient in people with DMD.

A full-sized dystrophin gene is the largest in the human genome and would be too large to place into the virus vector used by Sarepta to insert the DNA sequence into the host.

So instead the biotech has engineered a cut-down version that produces a functional protein in an attempt to treat the disease.

Treatment options are limited, in Europe PTC Therapeutics’ Translarna (ataluren) is approved in patients whose disease is caused by a nonsense mutation.

Sarepta’s Exondys 51 (eteplirsen) is not available in Europe, but is approved in the US, although it is only aimed at around 14% of patients whose disease is amenable to exon-skipping drugs.

James Sabry, head of Roche Pharma Partnering said, “We are excited to enter this licensing agreement with Sarepta. By working together to provide SRP-9001 to patients, we hope to fundamentally transform the lives of patients and families living with this devastating disorder for which there are currently only limited treatment options.”

The companies anticipate the deal to close in the first quarter of 2020 following clearance from US competition authorities.