Clinical role of obinutuzumab in the treatment of naive patients with chronic lymphocytic leukemia

New Strategies Using Antibody Combinations to Increase Cancer Treatment Effectiveness

Antibodies have proven their high value in antitumor therapy over the last two decades. They are currently being used as the first-choice to treat some of the most frequent metastatic cancers, like HER2⁺ breast cancers or colorectal cancers, currently treated with trastuzumab (Herceptin) and bevacizumab (Avastin), respectively. The impressive therapeutic success of antibodies inhibiting immune checkpoints has extended the use of therapeutic antibodies to previously unanticipated tumor types. These anti-immune checkpoint antibodies allowed the cure of patients devoid of other therapeutic options, through the recovery of the patient’s own immune response against the tumor. In this review, we describe how the antibody-based therapies will evolve, including the use of antibodies in combinations, their main characteristics, advantages, and how they could contribute to significantly increase the chances of success in cancer therapy. Indeed, novel combinations will consist of mixtures of antibodies against either different epitopes of the same molecule or different targets on the same tumor cell; bispecific or multispecific antibodies able of simultaneously binding tumor cells, immune cells or extracellular molecules; immunomodulatory antibodies; antibody-based molecules, including fusion proteins between a ligand or a receptor domain and the IgG Fab or Fc fragments; autologous or heterologous cells; and different formats of vaccines. Through complementary mechanisms of action, these combinations could contribute to elude the current limitations of a single antibody which recognizes only one particular epitope. These combinations may allow the simultaneous attack of the cancer cells by using the help of the own immune cells and exerting wider therapeutic effects, based on a more specific, fast, and robust response, trying to mimic the action of the immune system.

Drugs under preclinical and clinical study for treatment of acute and chronic lymphoblastic leukemia

Targeted therapy has modernized the treatment of both chronic and acute lymphoblastic leukemia. The introduction of monoclonal antibodies and combinational drugs has increased the survival rate of patients. Preclinical studies with various agents have resulted in positive outputs with Phase III trial drugs and monoclonal antibodies entering clinical trials. Most of the monoclonal antibodies target the CD20 and CD22 receptors. This has led to the approval of a few of these drugs by the US Food and Drug Administration. This review focuses on the drugs under preclinical and clinical study in the ongoing efforts for treatment of acute and chronic lymphoblastic leukemia.

New developments in the treatment of chronic lymphocytic leukemia: role of obinutuzumab

Obinutuzumab is a novel glycoengineered type II anti-CD20 monoclonal antibody with a higher affinity for CD20 epitope, enhanced antibody-dependent cellular cytotoxicity and direct cell death, leading to superior cytotoxicity compared with rituximab. The approval of obinutuzumab by US Food and Drug Administration was based on a pivotal, phase III, randomized trial of chlorambucil monotherapy (n=118), chlorambucil plus obinutuzumab (n=333), or chlorambucil plus rituximab (n=330) in previously untreated patients with CLL. Obinutuzumab was administered intravenously as 1,000 mg on days 1, 8, and 15 of cycle 1 and day 1 of subsequent cycles. Obinutuzumab plus chlorambucil was associated with an overall response rate of 78% and a median progression-free survival of 26.7 months. Overall, obinutuzumab was fairly well tolerated in this pivotal study. The incidence of grade 3 or higher adverse events was infusion-related reactions (20%), neutropenia (33%), thrombocytopenia (10%), and infections (7%). Obinutuzumab in combination with chlorambucil is a safe and effective new treatment option for previously untreated elderly patients with CLL. It should become the new standard of care for these patients with significant co-morbidities who are not candidates for fludarabine-based therapy. Obinutuzumab combination therapy with several agents that inhibit kinases involved in the B-cell receptor signaling pathway, as well as many other agents utilized in the frontline and relapsed/refractory setting, is currently under investigation. As the results from these studies become available, the role of obinutuzumab is expected to expand to other settings.