Drug Development

Corbus brags about another PhII success for its lead drug, but shares slide early

Yuval Cohen, Corbus CEO

Corbus Pharmaceuticals has plucked out some positive data from its mid-stage cystic fibrosis study. But it didn’t help its stock price this morning.

While the Phase II goal for its add-on drug anabasum (JBT-101 or Resunab) was safety and tolerability — which the biotech says they hit — it was an efficacy signal they picked up in a high-dose group that drew most of the attention. There, the company says, a twice daily 20 mg dose of the drug triggered a 75% reduction in the annualized rate of pulmonary exacerbations requiring IV antibiotics compared to placebo cohort.

While Corbus touted the data as another sign of clinical progress, there was considerable chatter on Twitter attacking the results, which explains why shares are down 13% in pre-market trading.

TheStreet’s Adam Feuerstein, a frequent critic of Corbus, launched a full scale assault on the company, saying the data shows no signs of a clinical benefit and that researchers just got lucky on pulmonary exacerbations with a handful of cases to compare.

In this four-month study of cystic fibrosis patients, the Corbus drug failed to improve lung function compared to a placebo. Overall respiratory symptoms, measured by a cystic fibrosis patient questionnaire, also showed no difference between anabasum and placebo.

Corbus CEO Yuval Cohen responded:

We don’t comment on stock movements but it is noteworthy that there is a sizable short position in our stock that is probably having a bad hair day this morning…

There were a total of 85 patients recruited for this study, and the high dose was tested in the second part of the Phase II, weeks 5 through 12, with 30 patients getting a 20 mg single dose per day and 31 getting the twice daily dose. Eleven patients in the placebo arm were assigned to the drug groups and 24 patients continued on placebo.

Five patients withdrew due to adverse events — five on placebo, three on anabasum. And the researchers also highlighted some positive biomarker results as well.

The latest batch of mid-stage data follows another small Phase II for systemic sclerosis, an autoimmune disease of connective tissue, that helped add some positive attention for the company, which has been under an intense short attack. Using a composite score to gauge a response on a slate of key measures like lung function, the combined drug arm including patients on a range of doses of resunab (JBT-101) posted a median 33% CRISS score after 16 weeks of therapy, compared to 0% in the placebo group. And that marks a significant benefit for patients, says the biotech, with a p-value of 0.044 — not a great number, but within the margin needed to declare a win.

These small studies and subgroup analyses leave a lot to be desired, but Corbus CEO Cohen — never reluctant to boast about successes — believe it helps show that the company is on track to deliver in pivotal studies.

“The reduction in acute pulmonary exacerbations along with reductions in inflammatory cells and inflammatory mediators in sputum demonstrate the potential for anabasum as a new inflammation-targeting therapeutic in cystic fibrosis that can broadly target patients without regard to their specific CFTR mutations. The outcomes of this 16-week study indicate that anabasum has the potential to address the important unmet need for treatments that target inflammation in CF,” commented principal investigator James Chmiel.

Most of these patients were already taking Orkambi, a combo drug from Vertex which has proved to have a modest but effective impact on CF.

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