The migraine drugmaker in May agreed to an $11.6 billion acquisition deal by Pfizer Inc, which plans to spin off its non-migraine drugs into a new publicly traded company.

The same month, another Biohaven drug, troriluzole, failed to meet the main goal of a late-stage study testing it in patients with a progressive nervous system disorder.

On Thursday, Biohaven said its drug for ALS did not achieve statistically significant improvement in patients' performance of daily activities compared to a placebo in a mid-to-late-stage trial.

ALS is a progressive and life-threatening neuromuscular disease, and the average age for survival is 3-5 years after the onset of first symptoms.

(Reporting by Manas Mishra in Bengaluru; Editing by Shinjini Ganguli)