Vivus shares gain weight as patients slim down

When a pharmaceutical company announces strong results in late stage studies for a drug for a yet untapped market estimated to be worth billions, the Street reacts. Drugmaker Vivus Inc. (VVUS) found out exactly what's that like when it announced Wednesday its obesity drug candidate Qnexa helped patients lose weight and its shares rocketed about 70 percent.

Vivus said that the trials for the experimental weight-loss drug Qnexa met key weight loss goals in two late-stage studies. Patients taking Qnexa reduced their weight by up to 14.7 percent (with the full dose), on average, in one trial comprising more than 3,750 patients.