Treatment outcome for metastatic papillary and chromophobe renal cell carcinoma (RCC) patients treated with tyrosine-kinase inhibitors (TKIs) sunitinib and sorafenib

Abstract

5037 Background: Sunitinib (SUNI) and sorafenib (SORAF) are novel TKIs that have shown significant clinical activity in metastatic clear-cell RCC. Papillary (PAP) and chromophobe (CHRM) histologies represent the majority non-clear-cell RCC. The activity of SUNI and SORAF in non-clear cell histologies has not been evaluated. Methods: Clinical features at study entry and treatment outcomes were evaluated in all patients (pts) with metastatic PAP and CHRM RCC who received either SUNI or SORAF as their initial TKI treatment at one of five different cancer centers in France and USA between 2002 and 2006. Descriptive statistics were used to evaluate the collected data. Overall Response rate (ORR) was investigator-assessed per RECIST criteria. Fisher’s exact test was used for categorical variables and the Kaplan-Meier method was used to estimate survival (Overall Survival (OS) and progression-free survival (PFS)). Results: Median age for the 53 patients was 59 years and 64% were male. The number of patients with PAP and CHRM histologies were 41 (77%) and 12 (23%), respectively. Nephrectomy was performed in 87% of patients and 33/53 (62%) of pts were previously treated (26/33, 79%, with cytokines). ORR, PFS and OS for the entire cohort were 10%, 8.9 months (m) and 12.2 m, respectively. Twenty (38%) and 33 (62%) pts were treated with SUNI and SORAF, respectively. 3/12 (25%) of CHRM pts had an ORR vs. 2/41(4.8%) with PAP histology (P=0.07). PFS for CHRM pts was 9.3 m compared to 6.6 m for PAP pts (p=0.07). OS was not different across histologies and type of TKI received. SUNI treated pts had an ORR of 15% and PFS of 11.9 m compared to 6% (p=0.3) and 5.5 m for SORAF pts (p=0.002), respectively. Other factors found to be associated with shorter PFS include ECOG PS >0 (p=0.03) and hemoglobin< normal (p=0.02). Conclusions: TKI may have activity in metastatic CHRM RCC, similar to what is seen in clear-cell histology. Minimal activity however is noted in PAP RCC, justifying continued investigations of novel agents in this histology. No significant financial relationships to disclose.