ASCO GU 2018: High Dose Interleukin-2 and Response in 944 Patients with Metastatic Renal Cell Cancer (RCC): Data From the PROCLAIM Registry

San Francisco, CA ( Metastatic renal cell carcinoma (mRCC) is rarely a curable disease. While targeted therapies have radically changed the management of these disease and extended survival for many, they are not curative – all patients eventually progress. Similarly, which some patients on the novel immune checkpoint inhibitors appear to have durable response, these are still not cured patients. However, historically, high-dose IL-2 has demonstrated cure in a small percentage of patients – albeit associated with a high rate of adverse events.

High dose interleukin-2 (HD IL2) has traditionally been dosed every 8 hours for a maximum of 14 doses each cycle. In this study, the authors evaluated whether alternate dosing schedules and dose intensity affected achievement of complete response (CR) or partial response (PR) in the PROCLAIM registry, and in turn, perhaps reduced adverse events.

From 2006-2017, the PROCLAIM registry included 944 RCC patients; 257 (27%) women, 676 (72%) men. 844 (89%) were white. Histologic distribution: 624 (66%) clear cell, 93 (10%) medullary, 79 (8%) collecting duct, 78 (8%) chromophobe and 70 (7%) papillary. 207 (22%) had prior therapy with VEGF/mTOR. Best response was 51 (5.4%) CR and 169 (17.9%) PR; 263 (28%) progressive disease.

13 (1.4%) patients received q12 hour dosing while 830 (88%) received q8 hour dosing. 608 (64%) received 600 KIU/kg and 67 (7%) received 720 KIU/kg.

Median # of doses in cycle 1 was 10 for CR and PR patients at 600 KIU/kg and 9 for those with stable or progressive disease; In the 720 KIU/kg group median #doses was 11 for CR, 8 for PR, and 7 for stable or progressive disease. In cycle 2 median doses received was 7.16 for patients with CR, 7.02 for PR and 6.76 for stable disease; median dose intensity was similar at these two dose levels.

Comparing dose amount, the CR/PR rate was 31/122 for the 600 KIU/kg group and 5/19 for the 720 KIU/kg group, p = 0.085. Comparing dose frequency, the CR/PR rate was 49/162 for the q8hr group and 1/4 for the q12hr group, p = 0.65.

Ultimately, the authors noted that in this retrospective registry analysis, there is no difference in response rate based on dosing schedule, but the small number of subjects dosed q12 hours limits interpretation. There is a trend for response with higher median number of doses, perhaps indicating a need for longer duration.

Speaker: Tanya Dorff, MD

Co-Authors: Michael K.K. Wong, Joseph Clark, Gregory A. Daniels, Brendan D. Curti, Michael Morse, Howard Kaufman, David F. McDermott, David I. Quinn, Peter Zang, Nancy C. Gregory, Lisa Maria Eifler, Stephen Thomas, Marci White, Jatinder Singh, Janice P. Dutcher

Institution(s): Keck School of Medicine of USC, Los Angeles, CA; UT MD Anderson Cancer Center, Houston, TX; Loyola University Chicago Medical Center, Maywood, IL; University of California San Diego Moores Cancer Center, La Jolla, CA; Providence Cancer Center and Earle A. Chiles Research Institute, Portland, OR; Duke University Medical Center, Durham, NC; Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Beth Israel Deaconess Medical Center, Boston, MA; USC Keck School of Medicine Norris Comprehensive Cancer Center, Los Angeles, CA; USC Keck School of Medicine, Los Angeles, CA; Prometheus Laboratories Inc., Spring, TX; Prometheus Therapeutics and Diagnostics, Paradise Valley, AZ; Prometheus Laboratories Inc., San Diego, CA; Primary Biostatistical Solutions, Inc., Victoria, BC, Canada; Our Lady of Mercy Cancer Center, New York, NY

Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, Twitter: @tchandra_uromd at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA