Shares of

Pfizer

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rose Tuesday after the company announced that test results for an experimental stomach cancer drug were so good that the study was halted.

The study of the drug SU11248 was halted seven months ahead of schedule on the recommendation of an independent group of scientists monitoring the research. The recommendation was made in late January.

The study compared patients receiving a placebo vs. patients receiving the drug for gastrointestinal stromal tumor, or GIST. The placebo patients were given the option of taking the experimental drug once the test was halted.

"We are encouraged by this interim data analysis and believe this is a positive step towards establishing SU11248 as an option for patients with Gleevec-resistant GIST," said Dr. Joseph Feczko, Pfizer president of worldwide development. Gleevec is a cancer drug sold by

Novartis

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.

"Pfizer and study investigators are working together to provide SU11248 to those enrolled in the study as quickly as possible and hope this unique therapy will continue to provide meaningful clinical benefit for cancer patients," he said.

The phase III test of the drug is the last in a series of clinical trials before a company submits a drug application to the Food and Drug Administration. Pfizer also is conducting a phase III test of the drug for kidney cancer. The drug launches a two-pronged assault on cancer -- attacking tumors and choking off the blood supply to tumors to prevent their growth.

Pfizer's stock was up 75 cents, or 3%, to $25.66.