CHICAGO, Sha'ban 11, 1436, May 29, 2015, SPA -- Patients with colon and other cancers who have a specific defect in genes needed for DNA repair are far more likely to respond to a new class of drugs such as Merck & Co's Keytruda, which enlist the immune system to attack tumors, a new study has shown, Reuters reported. The small study, financed not by Big Pharma but by swimmers who raised charitable donations, tested Keytruda in patients with advanced colon and rectal cancers and found 92 percent of patients with the genetic defect had their disease controlled compared with 16 percent who did not carry the defect. -- SPA 21:46 LOCAL TIME 18:46 GMT www.spa.gov.sa/w