Catabasis Pharmaceuticals is looking to test its experimental Duchenne drug edasalonexent in a late-stage trial after posting the last of the data from its midstage work.
The data as a whole have been a mixed bag: The $63 million market cap biotech posted a phase 1 trial at the start of the year that showed its drug was found to be safe when given to adults and reduced levels of NF-kb, an inflammatory mediator that the company believes is activated in the very early stages of DMD and is critical to the progressive muscle degeneration seen in the disease.
The data were published in the Journal of Clinical Pharmacology, and the company saw its shares up 20% on that positive turn. Edasalonexent (a.k.a. CAT-1004) is an oral NF-kB inhibitor and—unlike other DMD therapies such as Sarepta's injectable Exondys 51 (eteplirsen), which was approved last year for a specific genetically defined group of patients—could potentially be used in patients regardless of their underlying mutation, says the company.
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But back in February, the Cambridge, MA-based biotech said the Part B of its so-called "MoveDMD" phase 2 trial, which was always the bigger test, failed to beat out placebo in 31 Duchenne patients with the measure of change in lower leg muscles.
Its shares were routed, and closed at just $1.38 at the end of trading when the news was posted.
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But the company pointed to an open-label extension portion of this test, known as Part C, that was still ongoing. Today, it revealed those data, which it says showed “positive efficacy” in regards to sustained disease-modifying effects, following 24 and 36 weeks of treatment with its med.
Across all key assessments of muscle function, the biotech reports that improvements were observed in the rate of decline after 24 and 36 weeks of oral 100 mg/kg/day edasalonexent treatment, when compared to the rate of change in the control period for boys prior to receiving edasalonexent treatment.
These data provide “clinically meaningful evidence” that edasalonexent “substantially slowed the progression of Duchenne muscular dystrophy (DMD),” the company said in statement.
It also said that “supportive changes in measures of muscle health” were seen, with muscle enzymes “significantly decreased” compared to baseline at 12 weeks and later time points (p < 0.05) and lower leg muscle MRI T2 rate of change was significantly improved in comparison to progression during the control period (p ≤ 0.05). No further detailed statistical data were shared.
Catabasis added that “no safety signals” were observed in the trial.
The biotech says with these latest data, along with a “supportive regulatory input from FDA,” it is now plotting a global phase 3 of edasalonexent in patients with DMD regardless of mutation type in the first half of 2018, with top-line results expected in 2020.
This test will be randomized, double-blind and placebo-controlled and will have “many elements in common” with the phase 2, including the patient population and endpoints. It will seek to enroll about 125 patients aged four to seven who have not been on steroids for at least six months.
The primary endpoint will be change in the North Star Ambulatory Assessment score after 12 months of treatment with edasalonexent compared to placebo. This will prove to be a make-or-break trial for the med.
“We are extremely excited to see edasalonexent change the trajectory of disease in the MoveDMD trial with substantially slowed disease progression,” said Jill Milne, Ph.D., CEO of Catabasis.
“Boys treated with edasalonexent stabilized; they experienced meaningful improvements in muscle function compared to the rates of change observed during the control period. Importantly, other supportive positive measures of muscle health were observed. We look forward to advancing edasalonexent as a disease-modifying therapy in a single phase 3 pivotal trial as soon as possible with the goal of providing a meaningful impact on disease progression for all boys affected by Duchenne," she said.
Aside from last year’s controversial approval of Sarepta’s DMD drug, research and regulatory updates for this rare but devastating muscle-wasting disease have been poor. Just last week, a panel of experts convened by the FDA overwhelmingly knocked back PTC Therapeutics’ filing for approval of ataluren in DMD.
The experts panned PTC for relying on post hoc analyses, not all of which were convincing, to make its case for approving the drug.
PTC pushed through to an advisory committee meeting despite ataluren having come up short in two clinical trials. The FDA refused to review applications from PTC following both clinical missteps.