Implications of Key Studies Presented at ASH

Craig Deligdish, MD

February 2011, Vol 2, No 1 - Meeting Highlights

More than 4300 abstracts were accepted for the 2010 annual meeting of the American Society of Hematology (ASH). As always, there were numerous presentations that enhanced our understanding of hematologic malignancies and contributed to improving current treatment approaches.

Several important studies examined the efficacy of treating patients with follicular non-Hodgkin lymphoma (NHL). At the Plenary Scientific Session, an Intergroup Study from England was presented, which compared the preliminary results of patients treated with rituximab versus a watch-and-wait strategy. Asymptomatic adult patients were randomized to either watchful waiting, treatment with rituximab weekly for 4 weeks, or treatment with rituximab for 4 weeks followed by maintenance therapy.

As might have been expected, both treatment groups had significantly prolonged time to initiation of new therapy and significantly prolonged progression-free survival (PFS). However, at the time of the report there was no difference in overall survival (OS) between any of the 3 arms of the trial.

Also presented was an update on the results of the PRIMA trial, a multicenter study which confirmed the benefit of 2 years of maintenance rituximab in patients who responded to induction treatment with a combination of rituximab and che mo therapy.

These trial results figured in the US Food and Drug Adminis tration’s decision on January 28, 2011, to approve this new indication. The consistent theme in both studies was that regardless of the upfront therapy, maintenance therapy with rituximab resulted in significantly im proved event-free survival without an improvement in OS.

Offering guidance to physicians treating patients with NHL, investigators from Italy led by Umberto Vitolo, MD, suggested that interim positronemission tomography (PET) scanning does not predict the outcome in patients with diffuse large B-cell lymphomas.

The group looked at the predictive value of PET scans performed after several cycles of R-CHOP (cyclophosphamide, doxorubicin, vincristine, prednisolone, and rituximab) chemotherapy and concluded that there was no predictive benefit to a positive interim PET scan, and that the majority of patients with positive interim PET scans still achieved a complete remission as determined by PET scans performed at the conclusion of therapy. Ultimately, the investigators concluded that a larger prospective trial was needed to better assess the prognostic value of interim PET scans in this patient population.

Adding to the understanding of the optimal use of PET scanning, the experience from a single institution in Korea was reported by Deok-Hwan Yang, MD, and colleagues, showing that negative interim PET scans did predict for improved OS and PFS in patients with diffuse large B-cell lymphomas.

Reporting on the result of a multicenter phase 2 trial, Robert Chen and colleagues detailed the findings of a study that examined the efficacy and toxicity of brentuximab vedotin (SGN- 35) in patients with relapsed and refractory Hodgkin lymphoma. All patients had failed prior autologous stem-cell transplant, with 70% of the patients having primary refractory disease.

The response rate in 102 patients was impressive, with more than 95% of patients exhibiting some degree of tumor shrinkage. Based on this and other studies demonstrating similar results in patients with anaplastic large-cell lymphoma, Seattle Genetics and Millen nium are planning to seek regulatory approval for the indications in both Hodgkin lymphoma and anaplastic large-cell lymphoma.

These studies, as well as others presented in this issue, will undoubtedly serve to shift clinical practice as they are further evaluated and incorporated into our body of knowledge