Denmark's Genmab has announced promising top-line results from a mid-stage study of Arzerra, which is partnered with GlaxoSmithKline, as a treatment for chronic lymphocytic leukaemia in previously-untreated patients.

In the study, Arzerra (ofatumumab) was given in combination with fludarabine and cyclophosphamide to 61 CLL patients. The complete remission rate was 32% in patients who received 500mg of ofatumumab and 50% for those on 1,000mg of the drug. The overall response rate was 77% in the 500mg treatment group and 73% in the other arm, Genmab said.

The Danish firm noted that there were no unexpected safety findings reported during treatment and within 30 days after last infusion. The most common adverse event reported was neutropenia, at 48%, and other common adverse events (greater that 15%) were nausea, leukopenia, rash, vomiting, pyrexia, headache and thrombocytopenia.

Genmab confirmed that the number of patients who experienced adverse events was similar between the two dose groups. One death was reported in the study and was judged by the investigator as unrelated to ofatumumab.

The CLL data comes almost three months after the US Food and Drug Administration’s Oncology Drugs Advisory Committee voted 10-3 that Arzerra was likely to offer clinical benefit for certain patients with CLL, despite initial concerns that the anti-tumour activity of the drug was difficult to quantify. However the agency extended the review period for the monoclonal antibody, pushing the deadline back by three months until the end of October, to review new chemistry and manufacturing data.

At the end of July, GSK and Genmab presented promising data from a Phase III study of intravenous ofatumumab in rheumatoid arthritis for patients who had not responded to methotrexate. After 24 weeks, subjects reported a 20% or greater improvement in the number of swollen and tender joints, as well as improvements in other disease-activity measures, the primary endpoint of the trial.