Non-Hodgkin lymphoma (NHL) affects over 400,000 people in the United States; its incidence increases with age. Treatment options are numerous and expanding, yet efficacy is often limited by toxicity, particularly in the elderly. Nearly 70% patients eventually die of the disease. Many patients explore less toxic alternative therapeutics proposed to boost anti-tumor immunity, despite a paucity of rigorous scientific data. Here we evaluate the lymphomacidal and immunomodulatory activities of a protein fraction isolated from fermented wheat germ. Fermented wheat germ extract was produced by fermenting wheat germ with Saccharomyces cerevisiae. A protein fraction was tested for lymphomacidal activity in vitro using NHL cell lines and in vivo using mouse xenografts. Mechanisms of action were explored in vitro by evaluating apoptosis and cell cycle and in vivo by immunophenotyping and measurement of NK cell activity. Potent lymphomacidal activity was observed in a panel of NHL cell lines and mice bearing NHL xenografts. This activity was not dependent on wheat germ agglutinin or benzoquinones. Fermented wheat germ proteins induced apoptosis in NHL cells, and augmented immune effector mechanisms, as measured by NK cell killing activity, degranulation and production of IFNγ. Fermented wheat germ extract can be easily produced and is efficacious in a human lymphoma xenograft model. The protein fraction is quantifiable and more potent, shows direct pro-apoptotic properties, and enhances immune-mediated tumor eradication. The results presented herein support the novel concept that proteins in fermented wheat germ have direct pro-apoptotic activity on lymphoma cells and augment host immune effector mechanisms.
Background
While many humanized monoclonal antibodies utilize complement-dependent cytotoxicity, the complement depleting effects of these antibodies and the impact of complement replacement on treatment response are not well-described.
Methods
We conducted a phase 2 trial involving patients with relapsed/refractory chronic lymphocytic leukemia (CLL). Patients were treated with ofatumumab with fresh frozen plasma (FFP) used as a source of complement replacement. The primary endpoint was objective response rate. Correlative endpoints included complement levels (C3 and C4) and complement activity (CH50) which was drawn at baseline and after ofatumumab with FFP administration.
Results
Among 12 enrolled patients, overall response rate was 83% with two patients (17%) achieving a complete response. While only two (17%) patients had low complement activity at baseline, eight (67%) developed low levels of complement activity after ofatumumab treatment with FFP replacement. The magnitude of complement depletion did not correlate with response. Adverse events were minimal. The combination of ofatumumab and FFP demonstrated tolerability and surprising activity in high-risk CLL patients.
Conclusions
The combination of ofatumumab and FFP demonstrated tolerability and surprising activity in high-risk CLL patients. Complement replacement should be studied further as a minimally toxic approach to improve efficacy of monoclonal antibody-based regimens.
Background: While many humanized monoclonal antibodies utilize complement dependent cytotoxicity, the complement depleting effects of these antibodies and the effect of complement replacement are not well-described. This study sought to examine complement levels and the effect of complement repletion after treatment with ofatumumab in patients with chronic lymphocytic leukemia (CLL). Methods: Twelve patients with relapsed or refractory CLL were treated with ofatumumab in combination with fresh frozen plasma used as complement replacement. The primary endpoint was objective response rate. Correlative endpoints included complement levels C3 and C4 and complement activity. Results: Adverse events were minimal, and efficacy was encouraging with an overall response rate of 83% and 2 patients (17%) achieving a complete response. While only 2 (17%) of patients had low complement activity at baseline, 8 (67%) developed low levels of complement activity. At a median follow-up time of 37 months the median progression-free survival was 12.5 months. Conclusions: While a minority of patients had low complement activity at baseline, a majority developed low levels of complement with ofatumumab treatment. The magnitude of complement depletion did not correlate with response. Future trials are needed to further explore complement replacement as a less toxic strategy to improve efficacy of monoclonal antibody-based regimens in CLL.
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