Gene therapies have been making waves in the pharmaceutical industry by providing curative treatments for challenging diseases in a single treatment. However, when it comes to Duchenne muscular dystrophy (DMD), the results of genetic innovation have been less clear.
The first breakthrough in the DMD market came in 2023 when Sarepta Therapeutics received FDA approval for Elevidys to treat non-ambulatory patients with DMD. This approval was later expanded to include ambulatory patients as well. Despite the upward trajectory in sales, Elevidys faced controversy during its approval process, with concerns raised about its efficacy.
Following Elevidys, a Pfizer treatment for DMD failed in a phase 3 trial, casting doubt on the gene therapy approach for the disease. DMD is characterized by the breakdown of the protein dystrophin, and gene therapies aim to deliver a variant of the dystrophin gene to trigger the production of the natural protein. However, the results from Pfizer’s trial showed higher levels of microdystrophin but no clinical benefit compared to a placebo.
Regenxbio has now emerged as a potential competitor in the DMD gene therapy market following Pfizer’s exit. The company’s therapy, RGX-202, has entered a pivotal trial after showing promising results in a phase 1/2 study. RGX-202 is unique in that it includes functional elements of the C-terminal domain of dystrophin, making it closer to the full-length protein.
Despite questions about using dystrophin as an efficacy biomarker, Regenxbio plans to leverage microdystrophin levels as a primary endpoint for accelerated approval. The company has reported consistent clinical benefits from the treatment, creating optimism in the DMD community.
Regenxbio expects to release results from the pivotal trial in 2026, offering hope for patients and their families. Other candidates beyond Regenxbio’s therapy are also in development, such as Solid Bio’s SGT-003, which has shown encouraging early results in ongoing studies.
While the road to effective gene therapy for DMD has been challenging, ongoing research and development efforts offer promise for the future of treating this devastating disease. Insmed, a biopharmaceutical company, has recently expanded the enrollment criteria for their Duchenne muscular dystrophy (DMD) gene therapy treatment. The company plans to continue dosing patients throughout this year before seeking accelerated approval.
In addition to this development, Insmed has received clearance to initiate a phase 1 trial for their DMD gene therapy, known as INS1201. This therapy delivers microdystrophin using an AAV vector, but with a unique approach – intrathecal delivery directly into the spinal fluid. Insmed’s CEO, Will Lewis, believes that this method holds great promise and referred to it as “where the magic is.”
The company’s goal is to conduct a dosing study with a small number of patients to determine the effectiveness and safety of this delivery method. By avoiding intravenous delivery, which can lead to therapy being filtered out by the liver, Insmed aims to provide a more targeted and efficient treatment for DMD patients.
While it is still early to predict the outcome of this novel delivery route, Lewis expressed optimism about the potential of their therapy to be curative. Alongside advancements from other biotech companies like Regenxbio, there is a growing sense of hope within the DMD research and patient community. Dr. Pakola, a researcher in the field, mentioned that there is a palpable feeling of progress and optimism towards finding transformative treatments for DMD.
As Insmed continues to push boundaries in DMD gene therapy research, the prospects for improved outcomes for patients with this debilitating condition are looking brighter. With a focus on innovation and patient-centric care, the company is paving the way for potentially groundbreaking treatments in the fight against Duchenne muscular dystrophy.
