Vertex Pharmaceuticals Inc. shares surged in the extended session Tuesday after the biotech drug maker announced positive results from clinical trials of its cystic fibrosis treatments. Vertex shares rallied 26% to $166.50 after hours. The company said data from clinical studies of its treatment candidates VX-152 and VX-440 showed an up to 12% average improvement in lung function in cystic fibrosis patients given the drugs. Cystic fibrosis is a genetic defect that causes an abnormal buildup of mucus in the lungs leading to chronic infection and progressive lung damage.
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