High-Dose IL-2 Still Important Treatment for Metastatic RCC

High-dose interleukin-2 remains an important treatment for patients with metastatic renal cell carcinoma, producing durable responses even in those patients with chronic renal insufficiency, according to the results of a single-center retrospective study conducted by Michael Hanzly, MD, and colleagues at Roswell Park Cancer Institute.

According to the results of the study, published in Urology, more patients than previously thought may be candidates for treatment with interleukin-2.

Despite well-documented durable responses, interleukin-2, approved in 1992, is associated with significant adverse events, restricting the widespread adoption of its use. In addition, interleukin-2 is used only in a carefully controlled hospital setting in select patients who are considered healthy enough to tolerate the treatment. Also, in recent years, multiple new treatments for renal cell carcinoma have been approved by the US Food and Drug Administration.

In this retrospective analysis, Hanzly and colleagues evaluated the response to interleukin-2 at their cancer center, specifically in those patients with impaired renal function.

The study included 906 patients at Roswell Park Cancer Institute with metastatic renal cell carcinoma who received first-line or second-line interleukin-2 between 2004 and 2011. Ninety-one patients were identified who had been treated with high-dose interleukin-2. Follow-up data were available for 88 patients; the median follow-up in these patients was 45 months.

Thirteen patients (14.8%) had impaired renal function before undergoing treatment with interleukin-2. Additionally, 70 patients had undergone radical nephrectomy and 2 had undergone partial nephrectomy prior to their cancer diagnosis.

The overall response rate for the cohort was 15.9%, including four patients who had a complete response to treatment. The median progression-free survival was 8.6 months, and the median overall survival was 35.5 months.

“Most reported trials of high-dose interluekin-2 have limited its use to patients with a serum creatinine level < 1.5 mg/dL,” the researchers wrote. “Although 14% of patients in our cohort demonstrated mild renal impairment, they were successfully treated with HDIL-2.”

More than 90% of patients with impaired renal function received 2 to 3 cycles of interleukin-2 compared with only 50.6% of patients with adequate renal function (P = .002). The median overall survival in patients with impaired renal function was 36 months compared with 27.2 months in those with adequate initial renal function.

The researchers found that a lower tumor stage was associated with a better response to treatment and a longer time from diagnosis to initiation of treatment.

“The data tells us that in our specialized setting, we can safely provide this treatment to more patients, even those with chronic renal insufficiency,” lead author Thomas Schwaab, MD, PhD, assistant professor in the departments of urology and immunology, said in a prepared statement. “Our clinical results continue to be impressive in this otherwise lethal disease.”