(Reuters) -KalVista Pharmaceuticals Inc said on Tuesday it has ended a mid-stage study for its drug to prevent recurrent swelling attacks in people with hereditary angioedema due to safety concerns, sending its shares down more than 40%.
The drug developer cited increased levels of liver enzymes in some patients, which could lead to liver damage if kept unchecked, for the termination.
"The current formulation will not meet our requirements for a best-in-class oral prophylactic therapy," Chief Executive Andrew Crockett said.
Last year, the trial was paused for a few months after the U.S. drugs regulator sought more information on pre-clinical studies and was resumed in September.
Hereditary angioedema is a rare disease characterized by recurrent episodes of severe swelling of the skin and mucous membrane.
Existing drugs from Takeda Pharmaceutical, CSL (OTC:CSLLY) Behring and Biocryst Pharmaceutical work in two ways - either by preventing these attacks or by treating them when symptoms arise.
KalVista said it would now focus its resources on another "on-demand" drug, sebetralstat, that aims to treat the disease when symptoms arise.
It is also testing another drug to treat diabetic macular edema in a mid-stage trial.
Shares of the Cambridge Massachusetts-based company were down at $7.74 in premarket trading.