(Reuters) - Synta Pharmaceuticals Corp shares soared as much as 47 percent in heavy trading after the company said preliminary results from a mid-stage study of its drug ganetespib in breast cancer patients supported an expansion of the study.
According to the design of the trial, it would advance to the second stage of enrollment if at least one patient achieved objective tumor response, a measure of reduction in tumor size.
The study, codenamed ENCHANT-1, showed that four patients achieved an objective tumor response.
"We believe these data are important in driving both the potential in multiple tumor types as well as partnering potential," Roth Capital analyst Joseph Pantginis wrote in a client note.
The company said it would continue to enroll up to 33 patients in each of the two patient groups being tested in the study.
The trial will now evaluate a combination of ganetespib and a widely used cancer drug called paclitaxel.
Ganetespib blocks a protein which assists other proteins involved in tumor development and progression in many solid cancers and blood cancers.
The company is also testing the drug in combination with another cancer drug in a late-stage trial for lung cancer. The drug is also being tested in patients with colorectal and blood cancers.
Synta shares were up 35 percent at $6.86 in afternoon trading on the Nasdaq. The stock touched a high of $7.45 earlier.
More than 14 million shares changed hands by 1310 ET, eight times the stock's 10-day average trading volume.
(Reporting By Vrinda Manocha in Bangalore; Editing by Maju Samuel)