Abagovomab

To determine whether abagovomab maintenance therapy prolongs recurrence-free (RFS) and overall survival (OS) in patients with ovarian cancer in first clinical remission.

Patients with International Federation of Gynecology and Obstetrics stage III to IV ovarian cancer in complete clinical remission after primary surgery and platinum- and taxane-based chemotherapy were randomly assigned at a ratio of 2:1 in a phase III, double-blind, placebo-controlled, multicenter study. Abagovomab 2 mg or placebo was administered as 1-mL suspension once every 2 weeks for 6 weeks (induction phase) and then once every 4 weeks (maintenance phase) until recurrence or up to 21 months after random assignment of the last patient. The primary end point was RFS; secondary end points were OS and immunologic response.

Characteristics of the 888 patients included: mean age, 56.3 years; Eastern Cooperative Oncology Group performance status, ≤ 1 in > 99% of patients; serous papillary subtype, 81.5%; stage III, 85.9%; and cancer antigen 125 ≤ 35U/mL after third cycle, 80.9%. Mean exposure to study treatment (± standard deviation) was 449.7 ± 333.08 days. Hazard ratio (HR) of RFS for the treatment group using tumor size categorization (≤ 1 cm, > 1 cm) was 1.099 (95% CI, 0.919 to 1.315; P = .301). HR of OS using tumor size categorization (≤ 1 cm, > 1 cm) was 1.150 (95% CI, 0.872 to 1.518; P = .322). The most frequently reported type of adverse event was an injection site reaction in 445 patients (50.2%), followed by injection site erythema and fatigue in 227 (25.6%) and 212 patients (23.9%), respectively. By the final visit, median anti–anti-idiotypic antibody level was 493,000.0 ng/mL, indicating a robust response.

Abagovomab administered as repeated monthly injections is safe and induces a measurable immune response. Administration as maintenance therapy for patients with ovarian cancer in first remission does not prolong RFS or OS.

Ovarian cancer (OC) is the fifth most common cancer in women. Unfortunately, more than 70% of cases are detected at an advanced stage with a risk of recurrence, after front line therapy, of over 75%. The need for new therapeutic strategies is extremely high.

The development status and the possible role of specific immunotherapy of abagovomab are discussed in the context of the possible therapeutic options for maintenance therapy in advanced OC. An overview of abagovomab, generation and mechanism of action, Phase I/II results and the status of the Phase II/III ongoing trial is given.

Abagovomab stimulates the humoral immune response and the cell-mediated immune response in the studies conducted to date. In the proof of concept (POC) study abagovomab prolonged overall survival in those OC recurrent patients who showed an immune response. Abagovomab has an excellent safety and tolerability profile. These characteristics make abagovomab an optimal candidate for a maintenance treatment for OC patients after frontline therapy. The final results of the Phase II/III pivotal study evaluating abagovomab in this setting will be available in the first half of 2011.