May 27 (Reuters) - BioCryst Pharmaceuticals Inc said its experimental drug for treating a rare immune disorder was effective in reducing the attacks of the disease in a mid-stage trial.

The drug, BCX4161, was compared with a placebo and was being tested in patients with hereditary angioedema (HAE) - a genetic disease characterized by sudden attacks of swelling of the skin or the mucous membranes, which can be disfiguring, painful and life-threatening.

Those treated with the drug had an average rate of 0.82 attacks per week, compared with 1.27 for those given a placebo.

(Reporting by Esha Dey in Bangalore; Editing by Savio D'Souza)