Sarepta and StrideBio Partner to Advance Gene Therapies for Rett Syndrome, Other Disorders

Sarepeta Therapeutics and StrideBio will collaborate to advance novel gene therapies for four genetic neurological disorders, including Rett syndrome, the companies have announced.

Under the agreement, StrideBio, which specializes in viral-based delivery systems for gene therapy, will conduct initial research, development, and manufacturing for the first four gene targets in these neurological disorders: MECP2 (Rett syndrome), SCN1A (Dravet syndrome), UBE3A (Angelman syndrome), and NPC1 (Niemann-Pick).

The main goal of the early development stage is to obtain investigational new drug approvals from the U.S. Food and Drug Administration, which are mandatory to start clinical trials.

In turn, Sarepta, a company focusing on precision genetic medicine, expands its gene therapy pipeline by gaining exclusive licenses on the selected targets. It also gains the possibility to extend licensing to four additional targets (for a total of eight) in neuromuscular and central nervous system diseases.

StrideBio owns a platform to create adeno-associated viral (AAV) vectors, a class of modified viruses that are used to deliver gene therapy. They are engineered to be harmless (non-infectious) and work to deliver functioning genes directly into specific cells and tissues.

One of the current challenges in gene therapy is that some people carry a natural immunity against AAVs, in the form of neutralizing antibodies that react against these vectors and prevent gene therapies from working. In addition, immune reactions against AAVs can also become toxic for patients. This limits the number of patients who can benefit from AAV-based gene therapies, as carriers of neutralizing antibodies are excluded from gene therapy trials and treatments.

StrideBio’s platform addresses this problem by creating novel AAV capsids, or protein shells, that enclose the genetic material to be delivered and are able to escape pre-existing neutralizing antibodies.

As such, the platform holds promise for gene therapies to be used in a greater number of patients, the company says.

These new capsids can also be engineered to improve specific delivery of gene therapy to tissues of interest in a particular condition.

Sarepta and StrideBio plan to address re-dosing challenges as well in patients who have received some sort of AAV-based gene therapy.

“With our partnership with StrideBio, Sarepta continues to build on its leadership position in gene therapies to treat rare diseases. We are excited to work with StrideBio and access its innovative AAV platform for next-generation capsids,” Doug Ingram, Sarepta’s president and CEO, said in a press release.

“Our partnership with StrideBio expands our research portfolio by up to eight new targets and … ensures that we gain access to new technology and targets while not distracting Sarepta from its near-term priorities,” he added.

Sapan Shah, PhD, StrideBio’s CEO, said: “This partnership will provide significant resources and expertise to enable StrideBio’s continued rapid expansion of our research and manufacturing platform, as well as accelerate the development of AAV gene therapies for multiple rare disease targets.”

“We are looking forward to working together with Sarepta to bring novel treatments to patients as quickly as possible,” he added.

Sarepta will pay StrideBio $48 million as upfront payment, in addition to future payments for development, regulatory, and commercial milestones for the four programs. StrideBio will also receive royalties on potential worldwide sales.

If the collaboration is expanded to the four additional targets, Sarepta will pay up to $42.5 million along with future milestone payments.