Diminished returns for cancer therapy.

Diminished returns for cancer therapy

Therapeutic trials of juiced-up white blood cells and an immune system stimulator are yielding disappointing results in cancer patients, according to data presented by the method's developer, Steven A. Rosenberg of the National Cancer Institute. He is now working on revisions of the approach.

Last year, Rosenberg and his colleagues described preliminary results as promising, and the process was widely heralded as a novel approach to cancer treatment. But after the first flush of success, the numbers are beginning to pale. In the initial report, 11 of 25 cancer patients in whom no other treatment had worked had a 50 percent or more reduction in tumor size, including one in whom signs of cancer disappeared (SN: 12/7/85, p.359).

At a talk given at the National Institutes of Health last week, Rosenberg said that only seven of the 104 patients treated thus far have had a complete disappearance of their cancer. Another 25 have had a measurable reduction in tumor size, with 15 of them having at least a 50 percent reduction. One patient died three days after completion of the therapy, Rosenberg says.

"Most patients do not respond,' says Rosenberg, who also characterizes the treatment as "very toxic.' One problem not addressed by Rosenberg at the meeting is infection with hepatitis A. Several such cases have occurred in patients receiving the treatment at other institutions involved in the evaluation. According to a National Cancer Institute spokesperson, clinical trials at the outside institutions were halted the first week in September until the source, suspected to be in the medium used to grow the immune cells, is identified and eliminated.

In the therapy, white blood cells are removed from the patient, incubated in the immune system stimulator interleukin-2, and put back into the patient along with more interleukin-2.

While recognizing that the combination treatment has its problems, Rosenberg maintains faith in the general idea behind it. "I'm hoping that we've demonstrated that this kind of approach is at least capable of mediating tumor regression,' he says.

He has already tried a further refinement, using white blood cells taken from the tumor itself. Following successful animal trials (SN: 10/4/86, p.222), a 36-year-old man with melanoma was treated in November.

Rosenberg is also trying straight interleukin-2, and he said at the meeting that so far two people have died as a result of leaky capillaries induced by the treatment. He and his colleagues report in the Dec. 12 JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION on 10 patients treated with high doses of interleukin-2. Three patients had partial regressions, though one of them failed to respond to a second treatment and died of a secondary tumor several months later.

Cancer specialist Charles G. Moertel of the Mayo Clinic in Rochester, Minn., in an accompanying editorial, expresses pessimism about interleukin-2, which he notes has "unacceptably severe toxicity and astronomical costs . . . not balanced by any persuasive evidence of true net therapeutic gain.'