According to a story from EurekAlert!, the results from a recent Phase 2 clinical trial suggest that a two drug combination could be a useful approach for people with rare, incurable cancers affecting the digestive tract. The two drugs used in the trial are dabrafenib and trametinib, which are inhibitors of the BRAF and MEK pathways, respectively. These two pathways have been previously identified as drivers of cancers of the digestive tract in some cases. The two cancers that were treated in the trial were small intestine adenocarcinoma and biliary tract cancer.
These cancers generally have poor rates of survival, and survival time in cases of advanced disease is often less than five months. All of the patients in the study had cancer which carried BRAF mutations. These mutations appear in about 15 percent of cases of these cancers. The combination treatment has the potential to substantially increase progression free survival time.
In the study, 13 of 32 patients with biliary tract cancer and two of three patients with small intestine adenocarcinoma saw the size of their tumor decrease with dabrafenib and trametinib combination treatment. The median survival time increased to 11.2 months and the median time before the cancer stopped responding to treatment was 7.2 months. Maximum progression free survival was more than a year, and maximum total survival time was around two years.
While these results may sound merely incremental, it is important to remember that both of these rare cancers have historically had extremely poor prognosis; they are very difficult to detect and are often at an advanced stage when they are discovered. In addition, most of the patients in the study had failed to respond to prior treatments like chemo. These results represent a significant improvement in outcomes for patients with small intestine adenocarcinoma and biliary tract cancer.
Dr. Zev Wainburg, who first presented these study results, says that these findings indicate that anyone diagnosed with biliary tract cancer should be tested for the relevant mutations that may indicate if these drugs will work. Prior research has found that combined MEK and BRAF inhibitors are also useful in other types of cancer, such as lung cancer, melanoma, and thyroid cancer.