GSK and Genmab announce positive top-line results from pivotal trial of ARZERRA® (ofatumumab) combined with chlorambucil in previously untreated chronic lymphocytic leukaemia

GlaxoSmithKline (GSK) plc and Genmab A/S (OMX: GEN) announced today that their Phase III study of ARZERRA® (ofatumumab) in combination with chlorambucil versus chlorambucil alone in patients with previously untreated chronic lymphocytic leukaemia (CLL) met its primary endpoint of progression free survival (PFS) as assessed by an independent review committee (IRC).

A total of 447 patients were enrolled in the study. A 9.3 month improvement in the time a patient lived without worsening of their disease (median PFS) was seen in patients randomised to ofatumumab and chlorambucil compared to patients randomised to chlorambucil alone (22.4 months vs 13.1 months; HR: 0.57; p<0.001).

There were no unexpected safety findings. The most common (≥1%) serious adverse events as reported by the investigator within 60 days of last treatment were neutropenia [including febrile neutropenia] (5%), anaemia (4%), pneumonia (4%), and pyrexia (2%). Infusion reactions were mild to moderate in severity with 3% of infusion reactions reported as serious.

“As the aim of treating CLL, particularly in the frontline setting, is to maximise progression free survival while minimising side effects, we are therefore encouraged by these promising results.” said Dr. Kathy Rouan, Vice President BioPharmaceutical Development, GlaxoSmithKline. “We are planning regulatory submissions in the EU, US, and other regions in the coming months.”

“We are delighted with the positive results from this trial which we believe may lead to ofatumumab plus chlorambucil as an additional treatment option for the care of patients with CLL,” said Jan van de Winkel, Ph.D., Chief Executive Officer of Genmab. “We look forward to submitting the study results, including secondary endpoints, to the International Workshop on CLL (iwCLL) in Cologne, Germany this September.”

About the study

This Phase III study (NCT00748189) included patients with previously untreated CLL considered inappropriate for fludarabine-based therapy. Patients in the study were randomised 1:1 to treatment with up to twelve cycles of ofatumumab in combination with chlorambucil or up to twelve cycles of chlorambucil alone. The primary endpoint of the study was PFS according to the International Workshop for Chronic Lymphocytic Leukaemia (iwCLL) updated 2008 National Cancer Institute-sponsored Working Group (NCIWG) guidelines, using an independent endpoints review committee.

About chronic lymphocytic leukaemia

CLL is the most common form of leukaemia in adults. Based on estimates by the American Cancer Society, CLL will account for more than 15,680 new cases and more than 4,580 deaths in the United States of America alone in 2013. At present, no curative chemotherapy is available.

About ARZERRA (ofatumumab)

Ofatumumab is not approved or licensed anywhere in the world for use in patients who have not received treatment for CLL. For Full US Prescribing Information, please visit: us.gsk.com/html/medicines/index.html and visit health.gsk.com for the EU SPC for the approved indication.

Ofatumumab is a human monoclonal antibody which targets an epitope on the CD20 molecule encompassing parts of the small and large extracellular loops (Teeling et al 2006). Ofatumumab is being developed under a co-development and commercialization agreement between Genmab and GlaxoSmithKline.