RESIRT Data on Sirtex's SIR-Spheres to Treat Renal Cell Carcinoma Presented at ESMO Congress
October 10, 2016—Sirtex Medical Inc. announced that the initial safety and efficacy results from the RESIRT pilot clinical study were presented in a poster session at the 2016 European Society for Medical Oncology (ESMO) Congress held October 7–11 in Copenhagen, Denmark.
The Australian-based RESIRT study is a single-arm, dose-escalation study of the company's SIR-Spheres yttrium-90 (Y-90) resin microspheres in patients with primary renal cell carcinoma (RCC) who were not suitable for curative therapy by surgical resection, ablation, or other conventional techniques.
An abstract of the RESIRT study poster, number 803P, by Paul de Souza, MD, et al is available online on page 278 of the ESMO Congress program. RESIRT is listed on the Australian New Zealand Clinical Trials Registry at www.anzctr.org.au under the identifier ACTRN12610000690055.
According to Sirtex, a total of 21 patients were treated with SIR-Spheres Y-90 resin microspheres in a serial manner across six dose-escalating cohorts with an intended radiation dose ranging from 75 to 300 Gy and an imminent stasis. The primary endpoint of the study was safety and toxicity at 30 days posttreatment with microspheres.
The company reported that in terms of the safety data presented, the intended doses were delivered without any dose-limiting toxicity. Furthermore, there were no serious adverse events related to SIR-Spheres microspheres. Fifteen (71%) of the 21 patients experienced 44 adverse events within 30 days posttreatment. Eight (38%) patients had grade ≥ 3 adverse events, all unrelated to SIR-Spheres microspheres. Eight patients (38%) had 12 adverse events (grade 1–2) that were related to SIR-Spheres microspheres, of which one occurred before microsphere treatment.
In terms of initial efficacy of SIR-Spheres microspheres, the best overall tumor responses were: partial response, 1/19 (5.3%); stable disease, 17/19 (89.5%); and progressive disease, 1/19 (5.3%).
The study investigators concluded, “This pilot study demonstrates good tolerability of SIRT at all dose levels including imminent stasis in treating primary tumors in RCC patients otherwise unsuitable for conventional therapy.”