The doctor who ran a controversial medical experiment at the Fred Hutchinson Cancer Research Center testified that, even after patients began developing a rare but fatal complication, he kept the experiment going because he thought he could save more lives than would be lost.

"I was sure it would work," testified Dr. Paul Martin, who was in charge of the experiment known as Protocol 126.

Martin said the early results of Protocol 126 showed great promise in reducing the number of severe cases of graft-versus-host disease, a serious and sometimes fatal complication of bone-marrow transplants.

For that reason, according to his testimony, Martin continued the experiment even after two of the first 14 patients developed graft failure. Other researchers at "The Hutch" agreed that more patients should be tested.

Ultimately, nine of 22 leukemia patients in that early version of Protocol 126 died of graft failure.

In all, at least 83 of 85 patients in Protocol 126 died of various causes.

Martin was the last defense witness to testify in the 8-week-old trial of a lawsuit against The Hutch. Spouses of five patients who died in the experiment 20 years ago are suing, claiming they weren't informed of all the risks.

Closing arguments are scheduled tomorrow.

In two days of testimony that concluded yesterday, Martin recounted that none of the early patients developed severe or fatal forms of graft-versus-host disease. Estimates of deaths caused by graft-versus-host disease in standard bone-marrow transplants have ranged during the trial from 10 percent to as much as 30 percent.

The first patient in the experiment suffered graft failure and died, but Martin said that his results were not attributed to the experiment. Most of that patient's donor marrow was lost in a laboratory mishap.

Later, a patient named Jackie Couch suffered from a rare type of graft failure, called graft rejection. But Martin testified that at that time he doubted the experiment was the cause.

"We certainly didn't believe it. We were willing to say that was a fluke, and we had these incredibly good results in preventing graft-versus-host disease. So it still looked extremely promising."

When another patient died of graft rejection in January 1984, Martin said he decided to continue the experiment, which removed a type of blood cell called a T-cell from the donor marrow.

"It was still possible, based on our thinking, that the results with T-cell depletion could improve overall results and that we were to some extent trading between two problems, graft-versus-host disease and graft failure, and we didn't know where the balance would tip," Martin testified.

As more patients suffered from graft rejection, the experiment was stopped and modified to remove patients with a good chance of being cured. That was because sicker patients were suffering less from graft failure, perhaps because they were receiving higher doses of radiation.

Graft failure continued to be a problem in later versions of the experiment, and The Hutch ultimately abandoned the protocol.

Defense attorney George Mernick teared up when he asked Martin if he believed that he was helping these patients.

"I believed that with my whole heart," Martin said. "And in fact, even looking back now, I can add up the total number who actually died of graft-versus-host disease, and it's a remarkably low number. In that respect, they were helped."

David Heath: 206-464-2136; dheath@seattletimes.com.