Coupling of an Acyl Migration Prodrug Strategy with Bio-activation To Improve Oral Delivery of the HIV‑1 Protease Inhibitor Atazanavir

HIV-1 protease inhibitors (PIs), which include atazanavir (ATV, <b>1</b>), remain important medicines to treat HIV-1 infection. However, they are characterized by poor oral bioavailability and a need for boosting with a pharmacokinetic enhancer, which results in additional drug–drug interactions that are sometimes difficult to manage. We investigated a chemo-activated, acyl migration-based prodrug design approach to improve the pharmacokinetic profile of <b>1</b> but failed to obtain improved oral bioavailability over dosing the parent drug in rats. This strategy was refined by conjugating the amine with a promoiety designed to undergo bio-activation, as a means of modulating the subsequent chemo-activation. This culminated in a lead prodrug that (1) yielded substantially better oral drug delivery of <b>1</b> when compared to the parent itself, the simple acyl migration-based prodrug, and the corresponding simple l-Val prodrug, (2) acted as a depot which resulted in a sustained release of the parent drug in vivo, and (3) offered the benefit of mitigating the pH-dependent absorption associated with <b>1</b>, thereby potentially reducing the risk of decreased bioavailability with concurrent use of stomach-acid-reducing drugs

Coupling of an Acyl Migration Prodrug Strategy with Bio-activation To Improve Oral Delivery of the HIV‑1 Protease Inhibitor Atazanavir

HIV-1 protease inhibitors (PIs), which include atazanavir (ATV, <b>1</b>), remain important medicines to treat HIV-1 infection. However, they are characterized by poor oral bioavailability and a need for boosting with a pharmacokinetic enhancer, which results in additional drug–drug interactions that are sometimes difficult to manage. We investigated a chemo-activated, acyl migration-based prodrug design approach to improve the pharmacokinetic profile of <b>1</b> but failed to obtain improved oral bioavailability over dosing the parent drug in rats. This strategy was refined by conjugating the amine with a promoiety designed to undergo bio-activation, as a means of modulating the subsequent chemo-activation. This culminated in a lead prodrug that (1) yielded substantially better oral drug delivery of <b>1</b> when compared to the parent itself, the simple acyl migration-based prodrug, and the corresponding simple l-Val prodrug, (2) acted as a depot which resulted in a sustained release of the parent drug in vivo, and (3) offered the benefit of mitigating the pH-dependent absorption associated with <b>1</b>, thereby potentially reducing the risk of decreased bioavailability with concurrent use of stomach-acid-reducing drugs

Discovery of Novel TLR7 Agonists as Systemic Agent for Combination With aPD1 for Use in Immuno-oncology

We have designed and developed novel and selective TLR7 agonists that exhibited potent receptor activity in a cell-based reporter assay. In vitro, these agonists significantly induced secretion of cytokines IL-6, IL-1β, IL-10, TNFa, IFNa, and IP-10 in human and mouse whole blood. Pharmacokinetic and pharmacodynamic studies in mice showed a significant secretion of IFNα and TNFα cytokines. When combined with aPD1 in a CT-26 tumor model, the lead compound showed strong synergistic antitumor activity with complete tumor regression in 8/10 mice dosed using the intravenous route. Structure–activity relationship studies enabled by structure-based designs of TLR7 agonists are disclosed