ASCO 2017: Phase II study of alternate sunitinib schedule in patients with metastatic renal cell carcinoma

Chicago, IL ( Dr. Jonasch and colleagues presented their results of a phase II study alternating sunitinib schedule for patients with metastatic renal cell carcinoma (mRCC) at today’s 2017 ASCO annual meeting genitourinary cancer poster session. Considering that sunitinib typically given in a 4 week on, 2 week off schedule (4/2) results in significant toxicity in the third and fourth week of therapy, the authors hypothesized that a 2 week on, 1 week off schedule (2/1) would result in improved toxicity profile without compromising oncologic efficacy.

In order to complete this trial, the authors utilized a multicenter, single arm approach. Patients were initiated on a sunitinib 50mg 2/1 schedule and dose alterations were performed if grade >3 toxicities were experienced. The primary outcome was percentage of patients who experienced grade >3 fatigue, diarrhea, or hand-foot syndrome (HFS). Secondary outcomes were (i) response rate, (ii) progression free survival (PFS), and (iii) dose reduction. Over a two-year period, 60 patients were enrolled in this phase II trial and 59 patients were treated. The median age was 65.5 years (range 45-92) and 24% of patients had grade >3 toxicity (95%CI: 13.6%-36.6%). The authors note that this is similar to the average toxicity profile of the 4/2 schedule of 25%-30%. Thirty-seven percent of patients responded to therapy, and among patients with secondary endpoint data available, median PFS was 19.3 months (95%CI 8.2-NR) and 59% of patients underwent dose reduction. A possible limitation of this trial is lack of a 4/2 dose schedule control arm.

The authors concluded that sunitinib administered in a 2/1 dose schedule did not result in a lower rate of grade 3 or higher fatigue, diarrhea or HFS when compared to historical data from trials employing a 4/2 schedule. Encouragingly, oncologic efficacy data showed a robust response rate and prolonged PFS, suggesting that patients tolerating sunitinib on a 2/1 schedule may not be at risk of inferior outcomes. Further toxicity kinetics and evaluation of patient quality of life metrics are ongoing.
Clinical trial: NCT02060370

Presented By: Eric Jonasch, The University of Texas MD Anderson Cancer Center, Houston, TX, USA

Co-Authors: Rebecca Slack, Daniel M. Geynisman, Matthew I. Milowsky, Kimryn Rathmell, Summer Stovall, Donna Juarez, Elizabeth R. Plimack, Nizar M. Tannir, Brian I. Rini

Written By: Zachary Klaassen, MD, Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre
Twitter: @zklaassen_md

at the 2017 ASCO Annual Meeting - June 2 - 6, 2017 – Chicago, Illinois, USA