ASH 2013: Obinutuzumab Beats Rituximab in Older CLL Patients

In a large trial of older, newly diagnosed patients with chronic lymphocytic leukemia (CLL), obinutuzumab outperformed rituximab in both response rate and progression free survival (PFS), suggesting that rituximab may no longer be at the top of every blood cancer-based treatment totem pole.

This information was presented at the 55th Annual Meeting of the American Society of Hematology (ASH) in New Orleans.

Like rituximab, obinutuzumab (otherwise known as GA101) is an anti-CD20 monoclonal antibody. Traditionally, although rituximab is a star against many blood cancers, it has never been especially effective in older CLL patients.

The trial

The trial randomized 781 patients into one of three treatment arms:

• Chlorambucil (118 patients)
• Chlorambucil plus rituximab (330 patients)
• Chlorambucil plus obinutuzumab (333 patients)

The trial's primary endpoint was PFS, and those patients in the treatment arm had a median PFS of 26.7 months, compared to 15.2 months for patients receiving rituximab.

Complete response rate in the treatment arm was superior as well, with a rate of 21 percent, compared to just 7 percent in the rituximab arm.

These results, presented by Valentin Goede, M.D., of the Center of Integrated Oncology Cologne-Bonn at the University Hospital Cologne in Germany, are not necessarily going to translate for younger patients, and this treatment has not been tested in that setting.

"We can say that obinutuzumab will replace rituximab in the treatment of elderly CLL patients when combined with a weaker chemotherapy backbone," Goede concluded.

Source: ASH