Getting Personal

Researchers attack patients' tumors with custom-tailored vaccines.

KATY HUMAN
PUBLISHED: 1:00 AM, THU MARCH 4, 2010
Talk about this article with other patients, caregivers, and advocates in the General Discussions CURE discussion group.
In 2003, Stephen Creel, a manager at a software company in Austin, Texas, suddenly started passing blood in his urine. He had just celebrated his 40th birthday with friends and his wife, who was pregnant with their daughter, and he was as fit as he’d been in years.

The diagnosis of kidney cancer—renal cell carcinoma—was “shocking,” Creel says.

His father-in-law, a cancer researcher, directed Creel to M.D. Anderson Cancer Center in Houston, almost 170 miles away, where oncologists were testing an experimental vaccine to treat kidney cancer. 

They surgically removed patients’ tumors, sent samples away for processing, and then re-injected cancer-specific proteins back into the patient. They were trying to activate the patients’ own immune system cells, train them to recognize cancer as an invader, and fight it off. 

“I really liked the idea of that, getting your body to do the work, not just chemicals,” Creel says.

Preventive vaccination, also referred to as immunization, has become a critical part of global public health. Since the body has a much easier time developing immunity against foreign proteins that come from viruses or bacteria, vaccines to prevent cervical and liver cancers (associated with viral infection) are already available. But tricking the body into fighting existing cancer has proved more complicated because most cancer cell proteins are similar to normal proteins, and the body is “educated” not to develop immunity against its own proteins. Nonetheless, treatment vaccines for prostate cancer, lymphoma, melanoma, and other cancer types are undergoing late-phase tests in people, and the results are inspiring restrained optimism. 

“We’re training the body to reject the tumor,” says Leisha Emens, MD, PhD, a breast cancer researcher and vaccine developer at Johns Hopkins University in Baltimore. The immune approach is unlike new types of chemotherapy, radiation, or hormonal therapy, Emens says. Treatment vaccines target cancer cells more precisely, have far fewer side effects, and may be less likely to foster drug resistance. “This works completely differently,” Emens says. “With immune-based therapy, you’re actually changing how the body responds to cancer.”

Emens and other cancer vaccine researchers caution that it could be years before clinicians routinely use this immunological approach to treat cancer. Scientists have been experimenting with the technique for decades, and have tripped over many obstacles. One of the most fundamental: The immune system discriminates “self” from “nonself” at a basic level. Viral or bacterial infections are “nonself” and perceived as a threat, but cancers come from the body’s own tissue, so the immune system generally develops “tolerance” and recognizes cancer cells as “self,” and does not respond.

But as scientific understanding of the complex immune system has grown, many of those obstacles are falling away. Today, the Food and Drug Administration is considering data from a phase 3 clinical trial of a vaccine against metastatic prostate cancer called Provenge (sipuleucel-T). The FDA will decide whether to approve the vaccine by May 1.

Talk about this article with other patients, caregivers, and advocates in the General Discussions CURE discussion group.
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