mRNA Delivery of a Panel of Single-Domain Antibodies for Combinatorial Deciphering of Therapeutic Targets for Covid-19 Related Cytokine Release Syndrome

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Project Summary/Abstract Severe COVID-19 patients who develop acute respiratory distress syndrome (ARDS) and multiple organ failures share a hyperinflammatory cytokine/chemokine expression profile. This clinical observation resembles the cytokine release syndrome (CRS) which was the leading cause of mortality in patients infected with SARS-CoV and MERS-CoV. US FDA have fast-tracked dozens of clinical trials to evaluate the efficacy of cytokine blockade therapies in the management of COVID-19 associated CRS. However, recent data released from majority of the trials indicated that blockade of one cytokine or Janus Kinase only marginally benefited patients regarding recovery time, and yet barely improved the mortality rate compared with that of standard care. Therefore, it is urgently needed that a preclinical evaluation tool available to the medical researcher and pharmaceutical companies that could help them identify the most effective combinations of therapeutic targets in the treatment of CRS. We propose to construct a single domain antibody (sdAb) library that contains a panel of sdAbs against clinically-characterized, significantly elevated cytokines and chemokines associated with COVID- 19 CRS. This library could be harnessed as a tool to compare and contrast the potency of different cytokine/chemokine blockade therapy in a humanized PBMC engrafted CRS mouse model. Moreover, the library allows the testing of simultaneous blockade of multiple cytokine/chemokines as a combinatorial therapy for the treatment of CRS which is hypothesized to be resolution to the issue. To accomplish this in a prompt way, the modality of the library will be sdAb- encodings mRNA which is encapsulated in lipid nanoparticle (LNP) to avoid the hassle with the protein production and formulation. OncoTrap will leverage the expertise in in vitro antibody screening and molecular evolution platform, as well as the lipid nanoparticle-based gene delivery system, which will be achieved in three specific aims. Aim 1 is intended to screen the sdAbs against the designated cytokine or chemokine with each of them shows nanomolar or sub-nanomolar binding affinity toward its target. Aim 2 is intend to characterize the PK profiles of sdAbs when they are delivered in the form of mRNA by LNP in vivo. In Aim 3, two representative sdAbs in the library will be tested in human PBMC engrafted CRS mouse model as the proof of concept study. Achievement of NIH-STTR phase I study will prepare the library for large-scale and systemic screening in the phase II, where the most effective therapeutics target(s) in the treatment of CRS will be identified.