Feasibility of prolonged use of interferon-alpha in metastatic kidney carcinoma: a phase II study

BACKGROUND

Interferon-alpha has proven effective in the treatment of metastatic renal cell carcinoma. However, the optimal schedule has not yet been determined. The authors have studied the efficacy and toxicity of prolonged use interferon-alpha2a (IFN-alpha) in metastatic renal cell carcinoma (RCC). Interferon-alpha was administered intermittently for outpatients.

METHODS

Seventy-five patients with metastatic RCC without prior biochemotherapy were treated. During the first month, the IFN-alpha dose was increased from 4.5 to 18 million units (MU) 3 times a week to define the individual maximal tolerated dose for each patient. The treatment was continued at the maximal tolerated dose with a 1-week pause each month until either progression or intolerable toxicity was observed or up to 2 years.

RESULTS

The overall response rate (5 complete response [CRs] and 8 partial responses [PRs]) was 17% (95% confidence interval, 10-28%). Stable disease was observed in 32 patients (43%). Three late objective responses (4%) occurred after 12 months treatment. The median progression free time of all patients was 12.3 months, and median survival time was 19.3 months. The median duration of response in CR/PR patients was 16 months. In multivariate analysis independent prognostic factors were poor performance status (P = 0.004), presence of bone metastases (P = 0.001), and time to metastases less than 24 months (P = 0.003), which predicted poor survival. Six patients (8%) discontinued the treatment because of fatigue, elevation of liver enzymes, or cardiac arrhythmias. No life-threatening side effects were observed.

CONCLUSIONS

Prolonged and intermittently administered IFN-alpha2a three times per week in 3 weekly cycles in metastatic RCC is a feasible and effective therapy. A prolonged treatment duration of more than 12 months for stable and responding patients is beneficial and may improve the outcome of patients with RCC.

Prognostic factors and survival in patients with metastatic renal cell carcinoma treated with chemotherapy or interferon-alpha

Prognostic factors and survival were analysed in 295 patients with metastatic renal cell carcinoma (MRCC), treated with either chemotherapy (1975-1990) or interferon (IFN) (1983-1990). The 3-year survival was 8 and 24% in the chemotherapy and IFN groups, respectively (P < 0.001). In the univariate analysis, age < or = 60 years, prior nephrectomy, more than 1 year since initial diagnosis and treatment for metastatic disease, ECOG performance status 0 or 1, absence of liver metastases, lower erythrocyte sedimentation rate (first hour), and < or = 10% weight loss, within the past 6 months, were correlated with improved survival. Sedimentation rate, performance status and weight loss remained independent prognostic factors from the results of a Cox regression analysis. Three prognostic groups were identified from a combination of these factors. In the poor and intermediate risk groups, no significant survival difference was observed between patients treated with chemotherapy and those treated with IFN. The 3-year survival estimates for good risk patients were 15 and 48% in the chemotherapy and IFN groups, respectively. Therefore, in MRCC, sedimentation rate, performance status and weight loss are easily assessable and reproducible prognostic variables for the identification of risk groups. We hypothesise that IFN may increase survival in good risk patients, but is as ineffective as chemotherapy in poor risk patients with MRCC.