Treatment of metastatic papillary renal cell carcinoma with immunochemotherapy with interleukin-2, interferon-alpha and 5- fluorouracil

15644 Background: Combined immunochemotherapy with interleukin-2 (IL-2), interferon-alpha (IFN-a) and 5-fluorouracil (5-FU) is an established first-line therapy for metastatic renal cell carcinoma (RCC). However, data on histologic parameters predictive of clinical benefit are rare. Methods: Treatment courses of 164 patients consisted of IFN-a at 9 x 106 IU on day 1 of weeks 1 and 4 and days 1, 3, 5 of weeks 2 and 3; and at 18 x 106 IU on days 1, 3, 5 of weeks 5–8. Interleukin-2 was administrated at 18 x 106 IU twice daily on days 3–5 of weeks 1 and 4; and at 9 x 106 IU on days 1, 3, 5 of weeks 2 and 3. Additionally, patients received 5-FU at 750 mg m-2 on day 1 of weeks 5–8. In 153 patients, radical nephrectomy had revealed 22 cases of papillary RCC (pRCC, 13.4%) and 131 cases of clear cell RCC (ccRCC, 79.9%). In the remaining 11 (6.7%) their disease was inoperable. The overall response rates were evaluated according to WHO criteria. Results: For ccRCC and inoperable disease, responses of 34.4% and 27.3% after one cycle and 28.8% and 16.7% after two cycles, respectively, were noted. In contrast, no patient with pRCC showed any response after two cycles of combined immunochemotherapy. Conclusions: No objective response was seen in patients with pRCC. Hence, immunotherapeutic agents must be questioned in this histologic subtype. No significant financial relationships to disclose.