Patients and Methods: One hundred fifty-two patients with metastatic renal cell carcinoma were treated. Treatment courses consisted of SC rIL-2 at 20 x 10(6) IU/m(2) three times per week in weeks 1 and 4, and at 5 x 10(6) IU/m(2) three times per week in weeks 2, 3, 5, and 6. Additionally, patients received SC rIFN alpha 2 6 x 10(6) U/m(2) once per week in weeks 1 and 4, and three times per week in weeks 2, 3, 5, and 6.

Results: There were nine (6%) complete responses (CRs) and 29 (19%) partial responses (PRs), for an overall response rate of 25% (95% confidence interval, 19% to 32%). The median duration of responses for CRs and PRs was 16+ and 9 months, respectively. Additionally, 55 patients (36%) had stable disease (SD). Fifty-nine patients (39%) had continued disease progression (PD) despite treatment, or went off study after less than 4 weeks of therapy. The majority of patients treated experienced fever, chills, malaise, nausea, vomiting, and anorexia, side effects that were mostly limited to World Health Organization (WHO) grade 1 and 2. However, one patient developed grade 4 CNS toxicity with extended somnolence. On cessation of therapy, the neurologic symptoms in this patient were fully reversible, with no neurologic deficiency.

Conclusion: In summary, this multiinstitutional home-therapy setting of SC rIL-2 and SC rIFN alpha 2 in patients with progressive metastatic renal cell carcinoma demonstrated drastically reduced systemic toxicity, while it confirmed the therapeutic efficacy of the low-dose SC immunotherapy combination schedule.