Capricor culls COVID-19 vax work but eyes phase 3 for Duchenne therapy

Capricor Therapeutics will get enrollment underway in a phase 3 trial for its Duchenne muscular dystrophy (DMD) cell therapy next quarter, while development of a COVID-19 vaccine is coming to a halt. 

The biotech announced the Lancet publication of midstage results for the DMD treatment CAP-1002 Friday morning after dropping the news the prior evening that its preclinical messenger RNA COVID-19 vaccine is now on the sidelines.

Work on the exosome-based jab was culled due to "current availability of vaccines for" COVID-19, Capricor said in its full-year 2021 earnings update after market close Thursday. Two months ago, CEO Linda Marbán, Ph.D., told Fierce Biotech that Capricor expected to ask the FDA this year about starting a booster trial of the shot.

The company will instead focus its resources on CAP-1002. After four doses, the treatment improved both skeletal and cardiac muscle function in patients with DMD, according to the Lancet publication. 

These results were originally issued in September 2021, but Marbán called the publication a "true validation of the work" Capricor has done on the cell therapy.

After signing a $30 million upfront distribution and commercialization deal with Nippon Shinyaku for the U.S. in January, Capricor now has the third-party validation that will "definitely drive business development" and attract trial enrollees, the CEO said. Capricor wants the cell therapy to be available globally through partners that the biotech is currently talking with, she added.


The trial mainly involved non-ambulatory patients, a group that represents about 60% of people with DMD and has "long been largely ignored" in clinical trials for the disease, said Craig McDonald, M.D., national principal investigator for the trial, in a joint interview with Marbán. The University of California, Davis professor said he expects the upcoming 70-patient phase 3 study, intended to be registrational, to "enroll very quickly." 

Marbán said the phase 3 trial, dubbed HOPE-3, is designed almost "exactly like" the mid-stage study, named HOPE-2. Upper limb function will again be the primary efficacy endpoint.

“Even though we are blessed with good health, things like going off your feet and being in a wheelchair would sort of be a landmark moment in which your life is permanently attenuated," Marbán said, explaining the importance of looking at upper limb function. "They feel that way, but they've been off their feet for a while and so for them, the ability to use their arms or hands to be able to brush their teeth, drink something, eat something, use the bathroom, brush their hair, brush their teeth, is of primary importance, especially since most of our kids are over 15 years of age, the last thing they want is their mommy brushing their teeth.”

The late-stage trial will also include video-based assessments in patients' home environments to observe trunk function, McDonald said, referring to the torso area.

Marbán and McDonald could see Capricor's cell therapy one day being paired with a gene therapy for the disease. Preclinical studies have shown CAP-1002 "works appropriately with gene therapy" and "should provide additional support," Marbán said. Two exon-skipping gene therapies have secured FDA nods for the disease, including Nippon's Viltepso and Sarepta's Vyondys 53.

Capricor's cell therapy is non-gene targeted, meaning it can be administered to any Duchenne patient.

"Whereas right now, patients with exons 1 through 17 are being excluded from the gene therapy trials just because of concerns about autoimmune-mediated inflammatory myopathy or myositis," McDonald said. Eventually, though, CAP-1002 could work "synergistically" with gene therapies and dystrophin restoration approaches, he added.

Gene therapies in the pipeline in this space include Pfizer's early-stage program. Data for that asset, referred to as PF-06939926, were pushed from 2022 to the first quarter of 2023 after a patient in the trial died, the Big Pharma said in late-2021. Sarepta also has several DMD therapies in its pipeline, including gene therapies and CRISPR gene editing candidates. 

Capricor is also testing CAP-1002 in patients hospitalized with severe COVID-19 who are on supplemental oxygen. The 60-patient phase 2 study will read out before the end of this quarter, so in the coming weeks, the CEO said. That trial is testing just one dose of the cell therapy, as compared to multiple doses in the Hope studies in patients with DMD. 

"We’ll work with the regulatory bodies to determine best next steps for that product in that indication," Marbán said. The deal with Nippon does not apply to CAP-1002's use in COVID-19.