Pantaleo: Final stage optimization of LN02 for pre-development (LN02op)
Since first identifying the novel gp120/gp41 interface bNAb LN02, the Pantaleo Laboratory has developed several optimized variants with increased potency that might confer protection from HIV infection when used in combination with other bNAbs. The best characterized LN02 variant, ML85, exhibits ~10-fold improved potency relative to the wild-type LN02 bNAb against a multiclade panel of pseudoviruses. LN02 ML85 has good production yield, stable protein biophysical properties, low off-target nonspecific binding, and pharmacokinetic (PK) properties in the humanized FcRn transgenic mouse model that are consistent with the pre-development criteria for a neutralizing antibody drug candidate. Since the discovery of LN02 ML85, additional rounds of mutational optimization have led to the discovery of 15 new LN02 variants with a further 3- to 5-fold increased potency against a panel of diverse pseudoviruses refractory to neutralization. These new variants all express at high levels in transiently transfected CHO cells, show no signs of aggregation, and have reduced nonspecific binding properties. The final-stage optimization studies supported by this funding will yield a set of 2-3 pre-development LN02 candidates (LN02op) with optimized potency, breadth, and drug-like properties.
Bioinformatics analyses can provide a strong predictive evaluation of the bNAb combinations needed to achieve optimal clinical benefit. In collaboration with Dr. Bette Korber at Los Alamos National Laboratory, the team will use a mathematical model to evaluate LN02 candidates in paired or triple combination with 10-1074, 3BNC117, and other advanced antibody partners. Optimal partners will be identified based on complementarity of breadth, potency of neutralization, and the ability to completely neutralize a virus at a given antibody concentration. These bioinformatics analyses will rank the relative predictive efficacies of the best two- and three-bNAb combinations. This will help guide the selection of bNAb combination partners to evaluate the
in vivo antiviral activity of LN02 variants in the NOD scid gamma (NSG) humanized mouse model for HIV-1 infection.
Mutations to extend antibody half-life (M428L/N434S substitutions in the Fc region) will be incorporated into a series of 10-12 optimized LN02 variants, with antibodies first produced at small scale to monitor any potential changes in protein production yield, antibody stability, biophysical properties, and neutralization activity. These initial tests will identify candidates with the best profile for advancement. A final set of 2-3 LN02 variants with the LS mutations will be scaled up in preparation for PK evaluation in hFcRn transgenic mice.
In vivo neutralization studies in NSG transgenic mice will be performed to evaluate bNAb monotherapies with 3 different LN02 variants. Dual or triple bNAb combination studies in the HIV-1 infected NSG mouse model will elucidate the neutralization activity of the LN02 candidates in combination with advanced bNAbs.
The grant is led by Giuseppe Pantaleo at Centre Hospitalier Universitaire Vaudois (CHUV) in collaboration with Dr. Bette Korber (LANL) and the University of Zurich.
1. Perform bioinformatics analyses to evaluate the combined anti-viral breadth of LN02 with other advanced bNAbs.
2. Generate LS extended half-life mutants of LN02 for evaluation in hFcRn mice.
3. Use the HIV-1 infected NSG humanized mouse model to evaluate the
in vivo neutralization activity of optimized LN02, either alone or in combination with other bNAbs.