Corbus Pharmaceuticals says Resunab beats out placebo in CF test

The biotech is hoping future trials will prove the drug's efficacy as it looks to chart a course to approval

Corbus Pharmaceuticals has posted positive top-line data from its midstage trial of Resunab in certain cystic fibrosis (CF) patients as it plots future trials and talks with regulators.

The Norwood, Massachusetts-based biotech said in a statement it was assessing its candidate anabasum (Resunab) in escalating doses and pitted it against placebo in patients with the fatal lung-scarring disease.  

The 16-week study dosed 85 patients without regard to their specific CFTR mutation, or infecting pathogens, and continued with all baseline treatment regimens.

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The med, the biotech reports, hit its primary objective by showing an “acceptable safety and tolerability profile at all doses,” with “no serious or severe adverse events related to the study drug.”

The anabasum cohorts showed a dose-dependent reduction in a number of acute pulmonary exacerbations, the data showed, which was defined as those requiring IV antibiotics compared to a dummy therapy.

Patients in the highest dose cohort of anabasum (20mg orally, twice a day) had a 75% reduction in the annualized rate of pulmonary exacerbations, compared to the placebo cohort.

In this high dose group, the biomarker endpoints of inflammatory mediators in the sputum including interleukin-8, neutrophil elastase and sputum immunoglobulin G were also reduced, as well as serum C-reactive protein. “A consistent reduction in multiple inflammatory cells, including total leukocytes, neutrophils, eosinophils, and macrophages was also observed in the sputum,” the company says.

On safety, 6 serious adverse events (SAEs) occurred the anabasum-treated patients, with the same numbers of SAEs also seen placebo-treated patients. After dosing, the biotech said that 10 patients stopped the study early: 3 withdrew consent, 5 withdrew due to adverse events (2 on placebo, 3 on anabasum), while 1 subject “was lost to follow-up” and 2 withdrew for “treatment-unrelated reasons.”

The biotech is looking to prove its theory that targeting the CB2 receptor pathway found in lymphocytes, dendritic cells, macrophages, glial cells and other immune cells can turn off a signal for chronic inflammation, and therefore help CF patients.

Corbus said it would now “engage in further evaluation of the data and design of the next clinical trial in partnership with CF experts,” which includes Cystic Fibrosis Foundation Therapeutics, the non-profit drug discovery and development affiliate of the Cystic Fibrosis Foundation, which supported the phase 2 study.

After these chats, Corbus “will enter into discussions with the relevant regulatory agencies,” it added. The drug already has orphan status from the EMA and a fast track tag from the FDA.

Barbara White, MD, CMO of Corbus, said: “We are delighted to see such consistency in data showing clinical benefit coupled with improvement in the inflammatory response in the lungs, especially given the 12 weeks of active dosing and past challenges of others in safely targeting inflammation in CF. We believe these findings reflect the novel mechanism of action of anabasum to activate resolution of innate immune responses without immunosuppression.” The company sees 2020 as the year for market approval, should all go well in future trials. 

It was initially up 10% premarket on the news, but swiftly fell into the red when some questioned its data. Bio Twitter was not please, with Adam Feuerstein from The Street, saying on Twitter: "Actually anabasum did nothing for CF patients. No change in lung function. Shoddy disclosure of exacerbation endpoint. cherry-picking data. Efficacy of anabasum in this CF study is close to a zero. A lot of hand waving in the PR to obscure negative or missing data."

And when it came to the 75% reduction in exacerbations, he said: "75% of what? Corbus doesn’t tell you number of exacerbations. At just 1 dose? Besides, these are “acute” exacerbations, a subset."

Back in 2015, the then tiny Corbus got a $5 million grant from Cystic Fibrosis Foundation Therapeutics for its sole asset, coming after it made the leap from the OTC market into Nasdaq (under the ticker $CRBP) with a market cap of less than $80 million.

As of yesterday, its market cap was just over $420 million, and has been talked up in the past as being a competitor to CF major Vertex. But the biotech believes that anabasum, which targets inflammation, could help all patients suffering from the disease; Vertex’ meds, Kalydeco and Orkambi, only treat a subset of CF patients.

The drug is also in testing for for a number of rare disorders, including scleroderma and dermatomyositis.