David Wight, a retired oil engineer in Anchorage, is a study participant who has been able to take every possible step to save his life. When bladder cancer began to spread in his abdomen, he was given three to 12 months to live. That was four and a half years ago.

On a recent Saturday, Mr. Wight, who is 75 but looks younger, refereed a boys’ soccer game, racing up and down the field with the players. The following Wednesday he rose at 3 a.m. to fly 3,300 miles to Houston, where he would arrive at about 5 p.m. He has been making that trip every other week for over two years to receive immunotherapy at M.D. Anderson. For about a year and a half, his disease has been in complete remission.

Until recently, he paid his own airfare. But a few months ago, Bristol-Myers Squibb, the maker of the drug being studied, began picking up the tab, even reimbursing him retroactively — about $50,000 so far.

He has five children: three in their 40s, a son, 16, and a daughter, 10. The younger two were only 10 and 5 when he learned he was ill, and the thought that he might not have survived to raise them still brings tears to his eyes. Describing the time he has gained to be with his family, he said, “I won a lottery that’s bigger than anybody could imagine.”

His cancer was diagnosed in summer 2010, after a test during a routine physical found cancer cells in his urine. A small tumor had invaded the wall of his bladder. Mr. Wight had his bladder removed at a hospital in Anchorage, and was told he needed no further treatment.

A year after the surgery, he and his doctors were horrified to find that a large tumor had wrapped itself around his colon. Only then did the doctors discover that he had a rare, aggressive type of bladder cancer, called plasmacytoid. His doctors consulted with a hospital in Seattle, which devised a treatment plan.

“They said one word that told me I was not where I wanted to be: ‘palliative,’” Mr. Wight said. He knew palliative treatment was meant to ease symptoms, but not cure the disease. “I said, ‘No thank you. We can do better than that,’” he recalled.