Inotuzumab ozogamicin plus rituximab therapy is not superior to other comparators for relapsed refractory B-cell Non-Hodgkin Lymphoma

On 5^th July 2017, Dr Nam Dang, from the University of Florida Health, et al. published study results in a Letter to the Editor of the British Journal of Haematology for a randomized, phase III, open-label study of inotuzumab ozogamicin plus rituximab (R-InO) treatment for patients with Relapsed/Refractory (R/R) aggressive B-cell Non-Hodgkin Lymphoma (B-NHL) (NCT01232556).¹

The study compared the efficacy and safety of R-InO with either rituximab plus bendamustine (R-B) or rituximab plus gemcitabine (R-G) in adults with R/R CD20+/CD22+ B-NHL who were not candidates for chemotherapy.

Patients were enrolled to the study (n=338) between February 2011 and May 2013 and randomized to receive R-InO (n=166) or investigator’s choice (IC) of either R-B (n=137) or R-G (n=35). The primary endpoint was Overall Survival (OS). Secondary endpoints were Progression-Free Survival (PFS) and Objective Response Rate (ORR).

Two interim analyses (IA) were planned at 40% and 70% of OS events. Since the IA 40% estimated HR > 0.9 for OS in R-InO vs IC, the study was terminated on 16^th May 2013.

Key findings:

• Median follow-up: R-InO; 14.9 (0.4–8) months and IC; 15.9 (0.1–31.2) months
• Median OS: R-InO vs IC was 9.5 (7.0–14.5) and 9.5 (7.7–14.1) months and not statistically significant: (P = 0.708; HR [95% Confidence Interval (CI)] = 1.1 [0.8–1.4])
• Median PFS: R-InO vs IC was 3.7 (2.9–5.0) and 3.5 (2.8–4.9) months and not statistically significant: (P = 0.27; HR [95% CI] = 0.9 [0.7–1.2])
• ORR: 41% (95% CI, 33–49%) for R-InO and 44% (36–51%) for IC (arm difference, 3% [–8–13%]; P = 0.714 

The study did not show treatment superiority for R-InO compared with IC in terms of OS. The authors noted that there are limited treatment options for patients with R/R aggressive B-NHL who are not candidates for high-dose chemotherapy, therefore, the efficacy shown for R-InO means that it remains a viable treatment option.