Immunotherapy of metastatic renal cell carcinoma

Renal cell carcinoma (RCC) evokes an immune response, which occasionally has resulted in spontaneous and dramatic remissions. In an attempt to reproduce or accentuate this response, various immunotherapeutic strategies have been studied. The most consistent antitumor activity has been reported with interferon-alpha (IFN-alpha) and interleukin-2 (IL-2). In recent years, randomized trials have suggested that high-dose, intravenous bolus IL-2 is superior in terms of response rate and possibly in terms of response quality to regimens that involve either low-dose IL-2 and IFN-alpha, intermediate- or low-dose IL-2 alone, or low-dose IFN-alpha alone. More significantly, investigations associated with those trials suggested that the potential exists for identifying predictors of response (or resistance) and limiting IL-2 therapy to those patients who hare most likely to benefit. Although the role of low-dose, single-agent cytokines is limited, combinations of cytokines with targeted therapy may have merit. Several studies, including 2 completed, large, phase 3 trials of interferon plus bevacizumab versus interferon alone, have demonstrated superior efficacy with the combination regimen compared with cytokine monotherapy and suggested the potential of an additive effect that requires further exploration. For patients who are unlikely to benefit from IL-2 or who are unable to receive it, the emergence "targeted immunotherapy" offers hope for improved clinical outcome. Improvements in patient selection, novel agents, and combination therapy will be required to optimize the benefits of immunotherapy in metastatic RCC as the list of effective therapies grows.

Treatment selection for patients with metastatic renal cell carcinoma: identification of features favoring upfront IL-2-based immunotherapy

The availability of approved agents with distinct mechanisms of action (immunotherapy, vascular endothelial growth factor pathway, and mTOR inhibitors) has complicated treatment decisions for patients with advanced kidney cancer. High-dose IL-2 therapy is the only treatment that can produce durable complete responses; however, it has significant side effects and the vast majority of patients do not benefit. Thus, identifying the optimal patients to receive first-line IL-2 therapy is a priority. Past studies have identified some clinical features that might be associated with benefit from IL-2-based immunotherapy. Subsequent investigations of tumors from patients treated with IL-2 suggested that response was unlikely in patients with tumors with papillary features or low carbonic anhydrase IX (CAIX) expression. A model combining histologic features and CAIX expression separated patients into two groups of roughly equal size, with 96% of long-term responding patients being in the favorable prognostic group. This model is currently undergoing prospective validation. More recent studies involving gene expression profiling and array CGH have begun to identify additional features that might predict response to IL-2 therapy. Taken together, these data offer the possibility to limit the use of this toxic therapy to those most likely to benefit.

The application of high-dose interleukin-2 for metastatic renal cell carcinoma

Renal cell carcinoma (RCC) evokes an immune response, which has occasionally resulted in spontaneous and dramatic remissions [1-3]. In an attempt to reproduce or accentuate this response, various immunotherapeutic strategies have been studied. The most consistent anti-tumor activity has been reported with interferon alfa (IFN-alpha) and interleukin 2 (IL-2). In recent years, randomized trials have suggested that high-dose intravenous bolus IL-2 is superior in terms of response rate and possibly response quality to regimens that involve either low-dose IL-2 and IFN-alpha, intermediate- or low-dose IL-2 alone, or low-dose IFN-alpha alone. As this list of effective therapies for RCC grows, improvements in patient selection will be necessary to ensure that the only therapy capable of producing durable remissions will remain available to the patients who should receive it [4-7].

Allelic loss on chromosomes 8 and 9 correlates with clinical outcome in locally advanced clear cell carcinoma of the kidney

PURPOSE

We correlated allelic loss on chromosomes 8p, 9p and 14q with clinical outcome in locally advanced conventional renal cell carcinoma.

MATERIALS AND METHODS

We analyzed radical nephrectomy specimens from 72 stage P3N0 conventional renal cell carcinomas by microsatellite loss of heterozygosity (LOH) analyses directed at chromosomes 3p, 8p, 9p and 14q (2 primers per chromosome). All patients were treated with surgery only. LOH results were correlated with disease-free survival using the Kaplan-Meier method.

RESULTS

We detected LOH on chromosome 3p in 60 of 64 (94%), on chromosome 8p in 19 of 59 (32%), on 9p in 21 of 67 (31%) and on 14q in 18 of 70 (26%) informative cases. Of the 72 patients 24 (33%) had recurrence during followup. On univariate analysis patients with tumors demonstrating LOH on chromosomes 8p and 9q were at high risk for recurrence (p = 0.01). The correlation of recurrence with LOH approached significance for the individual chromosomes 8p and 9p (p = 0.10 and 0.14, respectively). No correlation was observed of LOH on chromosome 14q with recurrence (p = 0.42). The correlation of tumor grade with risk of relapse also approached significance (p = 0.12). On multivariate analysis LOH on chromosome 8p was a more powerful predictor of recurrence than tumor grade. When combinations of LOH on chromosomes were tested, LOH on chromosomes 8p and 9p was the most powerful predictor of recurrence (p = 0.006).

CONCLUSIONS

LOH on chromosomes 8p or 9p may provide prognostic significance in patients with locally advanced renal cell carcinoma.