Conference Report: Pursuing Progress Against HIV-Related Cancers
, by NCI Staff
At the recent annual Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle, several NCI researchers and NCI-funded investigators presented new findings on HIV-related cancers.
While the conference was fairly wide-ranging, some of the more interesting and clinically applicable findings evolved around a better understanding of AIDS-related malignancies, explained Robert Yarchoan, M.D., director of the Office of AIDS and HIV Malignancy in NCI’s Center for Cancer Research.
Kaposi sarcoma is one of the most common AIDS-related malignancies worldwide, with a particularly high incidence in parts of Africa. Several studies highlighted the evolving treatment landscape for this cancer.
Jeffrey Martin, M.D., University of California San Francisco, and colleagues from Makerere University College of Health Sciences in Uganda, presented findings at the meeting from a study in which they identified three factors that can be easily measured at the bedside and that predict which Kaposi sarcoma patients will fail to respond to antiretroviral therapy alone (ART) and require chemotherapy—an expensive and difficult treatment in a country with limited healthcare resources. These factors were: the number of anatomic sites with Kaposi sarcoma, Karnofsky Performance Status (a measure of general functional impairment), and hemoglobin levels.
This information, the researchers concluded, may help guide clinicians’ discussions about prognosis with their patients and whether to add chemotherapy to their treatment.
Mark Polizzotto, M.D., of the HIV and AIDS Malignancies Branch, and colleagues presented results from an early-phase trial that tested pomalidomide (Pomalyst) in 22 patients with Kaposi sarcoma, 15 of whom were HIV-positive. Pomalidomide, an analog of thalidomide, works in part by modulating the immune system, enhancing the ability of immune cells to kill tumor cells. Studies have shown that Kaposi sarcoma is very responsive to a patient’s immune status, Dr. Yarchoan explained.
Sixteen patients on the study had tumor regressions, including four with complete responses and 12 with partial responses. NCI conducted the trial under a cooperative research agreement with Celgene Corp., the manufacturer of pomalidomide. Jerome Zeldis, M.D., Ph.D., the company’s chief medical officer, was a co-investigator on the trial.
“The next step is to test the drug in a larger controlled trial to assess whether it improves the quality of life of patients and to identify which patients might benefit from this treatment,” Dr. Yarchoan said.
Numerous studies are focused on better defining who is at risk for HIV-related malignancies. This is particularly important because, due in large part to effective therapies, people with AIDS are now living to older ages. Because cancer incidence rises with age in general and because malignancies are more common in HIV-positive populations overall, the population of elderly persons with HIV can be especially vulnerable to cancer.
Elizabeth Yanik, Ph.D., and colleagues in NCI’s Division of Cancer Epidemiology and Genetics presented results from a study in which they investigated cancer risk in HIV-infected persons over the age of 65. They found a continued highly elevated risk of cancers seen in younger HIV-infected populations, including Kaposi sarcoma and non-Hodgkin lymphoma, as well as an increased risk of several other cancers, including Hodgkin lymphoma, and anal, liver, and lung cancers. Over a 5-year period, 10 percent of HIV-infected people in this age group were diagnosed with a cancer.
The sizable cancer risk in the elderly HIV-infected population, Dr. Yanik and her colleagues concluded, supports the need for cancer prevention and screening efforts in this group.
In another NCI-supported study, Keith Sigel, M.D., of Mt. Sinai Hospital in New York and colleagues found that an indicator of immune status could predict lung cancer risk among HIV-infected persons. In the study, which involved nearly 4,000 HIV-positive participants in the Veterans Aging Cohort Study, low numbers of CD4+ immune cells were associated with a significantly higher risk of developing lung cancer.
Although smoking history was the most important factor for predicting risk in these patients, the finding provides evidence that HIV-associated immune system suppression may also be a contributing factor, Dr. Sigel reported.
“The progress we’ve made over the past several decades in treating people living with HIV has been remarkable, as presenters pointed out time and again at the CROI meeting,” Dr. Yarchoan said. “However, as the population of HIV-infected persons increases and as these individuals are living longer, malignancies are looming as an increasingly important complication. It will be important to develop strategies to prevent malignancies in this population and to improve our treatment of them when they occur.”