The goal of the proposed studies is to continue and expand GlycoT?s research in a Phase I SBIR study to establish a robust and scalable process for production of hypersialylated glycoforms of intravenous immunoglobulin (IVIG) with markedly enhanced anti-inflammatory activity. We will achieve this goal by exploiting an innovative chemoenzymatic glycosylation remodeling technology to produce the glycoengineered IVIG and to test their efficacy in animal models. IVIG is a mixture of antibodies prepared from the pooled sera of thousands of healthy donors. High dosage of IVIG (1-2 g/kg) has been widely applied to treat autoimmune disease and chronic inflammation, such as rheumatoid arthritis (RA), with multi-billion-dollar annual sales globally. Despite its wide applications for treatment, current IVIG preparation has distinct limitations, including long time infusion (4- 6 h), variable efficacy, shortage of supplies, and side effects. As a result, alternatives for IVIG with more potent therapeutic efficacy (thus much lower doses) and minimal side effects are highly desired. While the precise molecular mechanisms for the anti-inflammatory activities of IVIG is still not well-understood, recent studies in animal models have suggested that the sialylated Fc glycoform of IVIG, which is a minor component consisting of ca. 10% of IVIG, could be the major active form that confers the anti-inflammatory activities. It has been demonstrated that the enrichment of the Fc sialylation glycoforms could achieve full activity of IVIG in several mouse models of autoimmune disease with less than 10% of the doses of commercial IVIG. Therefore, modification of IVIG with full sialylation points to a very promising approach to improving the therapeutic efficacy. Attempt to increase Fc sialylaton of IVIG by sequential galactosylation and sialylation of IVIG has been pursued, but met with only partial success due to the tremendous heterogeneity of the original glycoforms of IVIG, the relatively low efficiency of enzymatic sialylation, and side reactions. In this application, we apply a chemoenzymatic platform technology originally developed at University of Maryland to achieve fully Fc sialylated glycoform of IVIG. In the phase I study, GlcyoT has successfully established an efficient, scalable chemoenzymatic process for producing gram-scale of hypersialylated glycoforms of IVIG. The Fc glycan of engineered IVIG is more than 95% tetra-sialylated and exhibited 10-fold higher anti-inflammatory activity than the commercial IVIG in a mouse model of rheumatoid arthritis. The proposed Phase II study will further scale up the IVIG glycan-remodeling technology, establish a rigorous quality control system, and carry out intensive efficacy, toxicity, and pharmacodynamics study, paving the way for further preclinical studies and future human clinical trials.
