BioBlast sets sights on PhIII after efficacy prompts early halt of mid-stage study

BioBlast Pharma ($ORPN) has posted a glimpse at the data that prompted it to wrap up a Phase II trial after enrolling just one-third of the targeted number of patients. And while there is very little data available publicly to support BioBlast's optimism, the company thinks it has a strong enough hand to start discussing a Phase III trial with the FDA.

BioBlast CEO Colin Foster

Tel Aviv, Israel-based BioBlast stopped the open-label trial early on the basis of an interim analysis of 25 patients with oculopharyngeal muscular dystrophy (OPMD). The genetic disorder causes muscle wasting that ultimately renders people unable to swallow. To gauge whether its drug, Cabaletta, can help treat these symptoms, BioBlast x-rayed the mouths and throats of participants to see how deep material passed before and after they received the drug. Of the 12 patients assessed, 6 improved and 4 stabilized on the Penetration Aspiration Score 24 weeks after treatment with Cabaletta.

BioBlast also reported improvements in timed drinking tests, swallowing quality of life symptom scores and muscle strength, leading it to conclude that the ethical thing to do would be to wrap up the study early and power toward Phase III. However, in doing so, BioBlast has left itself with a set of data that has some limitations. While BioBlast enrolled 25 patients before halting recruitment, it only has Penetration Aspiration Scores for 12 participants because of failings at the Israeli trial site. The failings means BioBlast lacks Penetration Aspiration Scores for seven patients enrolled in Israel.

These patients were excluded from the interim analysis because faulty radiological procedures at the Israeli site rendered their baseline results uninterpretable. The 5 patients who were evaluated in Israel were also affected by the "technical radiological failure of their baseline study," BioBlast Chief Development Officer Dalia Megiddo told investors on a conference call, but went on to be measured "after being on treatment for a few weeks or months."

As such, the gap between the baseline and follow-up measurements in Israel was shorter than 24 weeks. "Yet ... we do not detect any difference between their results and those of the patients enrolled in Canada," Megiddo said. Both of the patients who deteriorated were evaluated in Canada. Half of the participants whose scores improved following treatment were enrolled in Israel.

The plan now is to use these data as the basis for discussions with FDA about a Phase III trial. If everything goes to plan, BioBlast will start the study next year. Shares in the Israeli biotech closed up 7.5% on the day of the news.

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