[Interleukin 2 based ambulatory therapy of metastatic renal cell carcinoma]

In metastatic renal cell carcinoma, strictly immunomodulatory maneuvers using systemic interleukin-2 have produced objective tumor remissions and led to an effective palliation. The goals of an improved cost effectiveness and therapeutic index of interleukin-2 require the design of risk factor adapted individual therapeutic strategies for the outpatient setting.

In 215 consecutive single institution patients with advanced metastatic renal cell carcinoma, the efficacy and tolerance of different subcutaneous recombinant interleukin-2 (rIL-2) based home therapies was assessed. Independent risk factors at pre-treatment level were identified and patient survival was compared between risk groups and therapies. Treatment consisted of s.c. rIL-2 alone and s.c. rIL-2 in combination with recombinant interferon-alpha 2 (rIFN-alpha 2), with or without intravenous 5-fluorouracil (5-FU).

Overall objective response rate in 215 patients was 33% (95% confidence interval, 26 to 39%). Among patients receiving rIL-2 alone (n = 16), there was 1 partial remission (overall response, 6%). In patients on rIL-2 and rIFN-alpha 2 in combination (n = 79), 6 complete and 16 partial remissions occurred (overall response, 28%). Of 120 patients receiving a combination of rIL-2, rIFN-alpha 2 and 5-FU, 13 patients achieved a complete and 34 a partial remission (lung, liver, local relapse, bone, adrenal, pleural, and thyroid metastases; overall response 39%). Duration of complete and partial remissions ranged from 10 to 55+ months, and 3 to 32 months, respectively, in rIL-2/rIFN-alpha 2 treated patients, and from 8+ to 47+ months and from 3 to 31+ months, respectively, in rIL-2/rIFN-alpha/5-FU treated patients. Of all patients 5% achieved long-lasting remissions and remain disease-free. In the majority of patients, systemic toxicity of s.c. rIL-2 based protocols was limited to grade 1 or 2 constitutional symptoms i.e., fever, chills, malaise, and anorexia; this allowed for an outpatient therapy. No life-threatening toxicity and no toxic deaths occurred.

The present outpatient rIL-2 triple drug combination protocol was as effective as the most aggressive i.v. rIL-2 regimen available; it substantially improved the therapeutic index and cost effectiveness of rIL-2 therapy in metastatic renal cell carcinoma stratified for risk.