Biological Therapy Doublets: Pairing Rituximab with Interferon, Lenalidomide, and Other Biological Agents in Patients with Follicular Lymphoma

Therapeutic Antibodies in Cancer Therapy

The therapeutic arsenal in solid tumors comprises different anticancer strategies with diverse chemotherapeutic agents and a growing number of biological substances. Large clinical study-based chemotherapeutic protocols combined with biologicals have become an important component in (neo-) adjuvant therapy alongside surgery in solid cancers as well as radiation therapy in some instances. In recent years, monoclonal antibodies have entered the mainstream of cancer therapy. Their first use was as antagonists of oncogenic receptor tyrosine kinases, but today monoclonal antibodies have emerged as long-sought vehicles for the targeted delivery of potent chemotherapeutic agents and as powerful tools to manipulate anticancer immune responses. There is a growing number of FDA approved monoclonal antibodies and small molecules targeting specific types of cancer suggestive of the clinical relevance of this approach.Targeted cancer therapies , also referred to as personalized medicine, are being studied for use alone, in combination with other targeted therapies, and in combination with chemotherapy. The use of monoclonal antibodies in colorectal and gastric cancer for example have shown best outcome when combined with chemotherapy, even though single agent anti-EGFR antibodies seem to be active in particular setting of metastatic colorectal cancer patients. However, it is not well defined whether the addition of anti-VEGF - and anti-EGFR strategies to chemotherapy could improve outcome in those patients susceptible to colorectal cancer-related metastases resection. Among the most promising approaches to activating therapeutic antitumor immunity is the blockade of immune checkpoints, exemplified by the recently FDA-approved agent, Ipilimumab, an antibody that blocks the coinhibitory receptor CTLA-4. Capitalizing on the success of Ipilimumab, agents that target a second coinhibitory receptor, PD-1, or its ligand, PD-L1, are in clinical development. This section attempts to discuss recent progress of targeted agents and in tackling a more general target applicable to gastrointestinal cancer .

Overcoming rituximab drug-resistance by the genetically engineered anti-CD20-hIFN-α fusion protein: Direct cytotoxicity and synergy with chemotherapy

Treatment of patients with B-NHL with rituximab and CHOP has resulted in significant clinical responses. However, a subset of patients develops resistance to further treatments. The mechanism of unresponsiveness in vivo is not known. We have reported the development of rituximab-resistant clones derived from B-NHL cell lines as models to investigate the mechanism of resistance. The resistant clones exhibit hyper-activated survival/anti-apoptotic pathways and no longer respond to a combination of rituximab and drugs. Recent studies reported the therapeutic efficacy in mice bearing B-cell lymphoma xenografts following treatment with the anti-CD20-hIFNα fusion protein. We hypothesized that the fusion protein may bypass rituximab resistance and inhibit survival signaling pathways. Treatment of the rituximab-resistant clones with anti-CD20-hIFNα, but not with rituximab, IFNα, or rituximab+IFNα resulted in significant inhibition of cell proliferation and induction of cell death. Treatment with anti-CD20-hIFNα sensitized the cells to apoptosis by CDDP, doxorubicin and Treanda. Treatment with anti-CD20-hIFNα inhibited the NF-κB and p38 MAPK activities and induced the activation of PKC-δ and Stat-1. These effects were corroborated by the use of the inhibitors SB203580 (p38 MAPK) and Rottlerin (PKC-δ). Treatment with SB203580 enhanced the sensitization of the resistant clone by anti-CD20-hIFNα to CDDP apoptosis. In contrast, treatment with Rotterin inhibited significantly the sensitization induced by anti-CD20-hIFNα. Overall, the findings demonstrate that treatment with anti-CD20-hIFNα reverses resistance of B-NHL. These findings suggest the potential application of anti-CD20-hIFNα in combination with drugs in patients unresponsive to rituximab-containing regimens.

Radioimmunotherapy combined with maintenance anti-CD20 antibody may trigger long-term protective T cell immunity in follicular lymphoma patients

Growing evidence suggests that the patient's immune response may play a major role in the long-term efficacy of antibody therapies of follicular lymphoma (FL). Particular long-lasting recurrence free survivals have been observed after first line, single agent rituximab or after radioimmunotherapy (RIT). Rituximab maintenance, furthermore, has a major efficacy in prolonging recurrence free survival after chemotherapy. On the other hand, RIT as a single step treatment showed a remarkable capacity to induce complete and partial remissions when applied in recurrence and as initial treatment of FL or given for consolidation. These clinical results strongly suggest that RIT combined with rituximab maintenance could stabilize the high percentages of patients with CR and PR induced by RIT. While the precise mechanisms of the long-term efficacy of these 2 treatments are not elucidated, different observations suggest that the patient's T cell immune response could be decisive. With this review, we discuss the potential role of the patient's immune system under rituximab and RIT and argue that the T cell immunity might be particularly promoted when combining the 2 antibody treatments in the early therapy of FL.