A study involving an experimental Bayer AG (BAYRY, BAYN.XE) cancer drug, regorafenib, showed it delayed the progression of a rare type of gastrointestinal tumor in patients who had been previously treated with other drugs.

BayerHealthcare, a Bayer unit, announced last month that it had submitted an application to the U.S. Food and Drug Administration seeking approval for regorafenib to treat patients with advanced colon cancer, and plans to submit an application as a treatment for gastrointestinal stromal tumors, or GIST, later this year.

The study looking at regorafenib in GIST involved 199 patients who had been previously treated with Novartis AG's (NVS, NOVN.VX) Gleevec or Pfizer Inc.'s (PFE) Sutent. The patients tumors had become resistant to Gleevec and Sutent, which is not uncommon as cancer finds new ways to grow. Researchers, led by George Demetri of the Dana-Farber Cancer Institute in Boston, said regorafenib targets an enzyme called KIT along with other pathways cancer uses to grow.

Two-thirds of the patients were given regorafenib while one-third of the patients were given a placebo drug. The study was designed to measure progression-free survival, which is a measurement of the time from the start of treatment until the disease gets worse or the patient dies. Patients in the placebo were offered regorafenib if their disease progressed.

The study showed median progression-free survival was 4.8 months in the patients receiving regorafenib compared with 0.9 month for patients in the placebo group. Because most patients in the placebo group were later treated with regorafenib, there was no statistically significant difference in overall survival, Dr. Demetri said.

The most common drug side-effects were hand-foot skin reactions like redness, swelling and pain, high blood pressure and diarrhea.

Separately, a study looking at another experimental drug afatinib, which is being developed by Boehringer Ingelheim Pharmaceuticals Inc. for use in some types of lung cancer, showed it slowed disease progression.

The study, also due for presentation Monday at ASCO, involved 345 patients whose cancers tested positive for a mutation called EGFR. That type of lung cancer is commonly seen in people who have never smoked and are of Asian descent.

About two thirds of the patients received afatinib and one-third received a combination of chemotherapy drugs pemetrexed and cisplatin, common lung-cancer treatments. The study showed patients treated with afatinib had a median progression-free survival of 11.1 months compared to 6.9 months for the chemotherapy group. Overall survival data aren't expected for about two years.

   -By Jennifer Corbett Dooren, Dow Jones Newswires; 
   jennifer.corbett@dowjones.com