Jørgen Petersen

First clinical use of ofatumumab, a novel fully human anti-CD20 monoclonal antibody in relapsed or refractory follicular lymphoma : results of a phase 1/2 trial

Ofatumumab is a unique monoclonal antibody that targets a distinct small loop epitope on the CD20 molecule. Preclinical data show that ofatumumab is active against B-cell lymphoma/chronic lymphocytic leukemia cells with low CD20-antigen density and high expression of complement inhibitory molecules. In a phase 1/2 trial evaluating safety and efficacy of ofatumumab in relapsed or refractory follicular non-Hodgkin lymphoma (FL) grade 1 or 2, 4 dose groups of 10 patients received 4 weekly infusions of 300, 500, 700, or 1000 mg. Patients had a median of 2 prior FL therapies and 13% had elevated lactate dehydrogenase. No safety concerns or maximum tolerated dose was identified. A total of 274 adverse events were reported; 190 were judged related to ofatumumab, most occurring on the first infusion day with Common Terminology Criteria grade 1 or 2. Eight related events were grade 3. Treatment caused immediate and profound B-cell depletion, and 65% of patients reverted to negative BCL2 status. Clinical response rates ranged from 20% to 63%. Median time to progression for all patients/responders was 8.8/32.6 months, and median duration of response was 29.9 months at a median/maximum follow-up of 9.2/38.6 months. Ofatumumab is currently being evaluated in patients with rituximab-refractory FL. This trial was registered at www.clinicaltrials.gov as #NCT00092274.

Ofatumumab, a human anti-CD20 monoclonal antibody, for treatment of rheumatoid arthritis with an inadequate response to one or more disease-modifying antirheumatic drugs: Results of a randomized, double-blind, placebo-controlled, phase I/II study†

OBJECTIVEnTo investigate the safety and efficacy of ofatumumab, a novel human anti-CD20 monoclonal antibody (mAb), in patients with active rheumatoid arthritis (RA) whose disease did not respond to > or = 1 disease-modifying antirheumatic drug.nnnMETHODSnThis combined phase I/II study investigated the safety and efficacy of 3 doses of ofatumumab. In part A (phase I), 39 patients received 2 intravenous (i.v.) infusions of ofatumumab (300 mg, 700 mg, or 1,000 mg) or placebo in a 4:1 ratio 2 weeks apart, using a specified premedication and infusion regimen. In part B (phase II), 225 patients received study treatment as per phase I in a 1:1:1:1 ratio. Safety was assessed by adverse events (AEs) and laboratory parameters. Efficacy was assessed by the American College of Rheumatology 20% criteria for improvement (ACR20), the Disease Activity Score in 28 joints, and the European League Against Rheumatism (EULAR) response criteria. B cell pharmacodynamics were also investigated.nnnRESULTSnAEs were predominantly reported at the first infusion and were mostly mild to moderate in intensity. Rapid and sustained peripheral B cell depletion was observed in all dose groups. In phase II, patients in all ofatumumab dose groups had significantly higher ACR20 response rates (40%, 49%, and 44% for the 300 mg, 700 mg, and 1,000 mg doses, respectively) than did patients receiving placebo (11%) at week 24 (P < 0.001). Overall, 70% of patients receiving ofatumumab had a moderate or good response according to the EULAR criteria at week 24.nnnCONCLUSIONnOur findings indicate that ofatumumab, administered as 2 i.v. infusions of doses up to 1,000 mg, is clinically effective in patients with active RA.

Pharmacokinetics and pharmacokinetic/pharmacodynamic associations of ofatumumab, a human monoclonal CD20 antibody, in patients with relapsed or refractory chronic lymphocytic leukaemia: a phase 1–2 study

The purpose of this phase 1–2 study was to investigate the association between the pharmacokinetic properties of ofatumumab, a human monoclonal CD20 antibody, and outcomes in 33 patients with relapsed/refractory chronic lymphocytic leukaemia receiving 4 weekly infusions of ofatumumab. The ofatumumab concentration profiles were fitted well by a two‐compartment model with different elimination rate constant at first infusion compared to the remaining infusions in line with the observed rapid and sustained B‐cell depletion. Exposure to ofatumumab was linked to clinical outcomes: high exposure was associated with higher probability of overall clinical response and longer progression‐free survival. This association still remained statistically significant even when adjusting for relevant baseline covariates including tumour burden. The trial was registered at http://www.clinicaltrials.gov (NCT00093314).