According to a recent article published in the journal Cancer, long-term, low-dose interleukin and interferon therapy produces anti-cancer responses with minor side effects in patients with advanced renal cell carcinoma.
Renal cell carcinoma (RCC) is the most common form of kidney cancer. Treatment of RCC depends on the age and general health of a patient as well as the stage of their disease. Although some treatment regimens may consider radiation therapy or chemotherapy, neither has proven to be very effective. The most promising treatment for RCC is surgery and immunotherapy (treatment utilizing the immune system to attack the cancer cells). Since 30% of patients have advanced disease at the time of diagnosis and RCC is often resistant to traditional chemotherapy drugs, the five-year survival rate is poor and treatment is difficult. Consequently, researchers are often exploring new treatment strategies for advanced RCC.
One of the most promising immunotherapies used to treat RCC is interleukin. Interleukin is often combined with other agents like interferon in trials to determine the best schedule and dose that will maximize response and minimize toxicity. Interleukin and interferon are both immune stimulating agents naturally found in the body. One type of interleukin researched in clinical trials is recombinant (laboratory-synthesized) interleukin-2 (rIL-2). Recombinant interferon alpha (rIF-alpha) is often used in combination with rIL-2 to further enhance the immune response. Both of these agents are associated with significant side effects, particularly when given in high doses.
Researchers from Italy recently conducted a clinical trial evaluating toxicity, immune response and overall response to indefinitely repeated cycles of low-dose rIL-2 and rIFN-alpha treatment. The trial involved 50 patients with advanced RCC who received rIL-2/rIFN following surgery on an outpatient basis for one month at a time, every four months. Approximately 15% of patients achieved complete or partial disappearances of their cancer. Three years following therapy, nearly half of the patients were still alive. Side effects from treatment were tolerably low.
Although there were fewer complete anti-cancer responses with this low-dose regimen, compared to results from previous trials evaluating high-dose regimens, survival rates were similar. This is encouraging, as it suggests that patients may one day be able to avoid the extremely severe side effects of high-dose approaches. Additional clinical trials comparing high-dose and low-dose strategies will further define the best treatment approach for patients with advanced RCC.
Patients with RCC may wish to speak with their physician about the risks and benefits of participating in a clinical trial evaluating low-dose interleukin and interferon or other promising therapeutic approaches. (Cancer, Vol 92, No 9, pp 2286-2296, 2001)