Zevalin Y-90 Good as Frontline Therapy in Advanced Follicular Lymphoma

The results of an international, multicenter phase II trial evaluating the efficacy and toxicity of fractionated 90Y-ibritumomab tiutetan (otherwise known as Zevalin) for patients with advanced follicular lymphoma indicate that the radioimmunotherapy (RIT) is an effective frontline therapy for these patients.

Y-90 Zevalin is a very convenient and effective form of therapy for lymphoma patients compared to traditional combination chemotherapy. Currently, Y-90 Zevalin is approved for the treatment of recurring, low-grade or follicular B-cell non-Hodgkin's lymphoma following the failure of at least one other treatment regimen, and for the treatment of newly diagnosed follicular lymphoma after a response to other frontline therapy.

This study is likely attempting to pave the way for Y-90 Zevalin to be approved as a frontline therapy in advanced stage follicular lymphoma.

Administering treatment

The study, by Tim M. Illidge, University of Manchester, Manchester Academic Health Sciences Centre, Wilmslow Road, Manchester U.K. and colleagues, recruited 74 patients with a median age of 61 years (ranging from age 28 to 80), 78 percent of whom were diagnosed with stage III-IV disease. Of these patients, 32 percent were considered intermediate, and 44 percent were considered high-risk according to the FLIPI (follicular lymphoma international prognostic index).

Patients were treated with two doses of 90Y-IT administered eight to 12 weeks apart. Those patients found to have at least 20 percent infiltration of bone marrow were given weekly infusions of rituximab for four weeks and then received RIT only if another check of their bone marrow revealed that infiltration had fallen below 20 percent.

This phase II trial's primary end point was an end to treatment response in the intention-to-treat population. Secondary objectives were safety and progression-free survival (PFS).

Examining response rates

After the study, researchers found the following results:

• Initial overall response rate (ORR): 94.4 percent (68 of 72 patients)
• Combined complete response (CR/CRu): 58.3 percent (42 of 72 patients). Nine patients subsequently improved response making an ORR of 95.8 percent (69 of 72 patients) and CR/CRu of 69.4 percent (50 of 72 patients).

After a follow-up, researchers found::

• At a median follow-up of 3.1 years, the estimated three-year PFS is 58 percent
• Treatment-free survival is 66 percent
• Overall survival is 95 percent
• Median PFS is 40.2 months. Thirty patients have experienced disease progression and 24 have required further treatment.

These findings were first presented at the ASH 2011 conference. The researchers are now reporting them in the Journal of Clinical Oncology.