Dual κ-agonist/µ-antagonist opioid receptor modulation reduces levodopa-induced dyskinesia and corrects dysregulated striatal changes in the nonhuman primate model of Parkinson disease.

OBJECTIVE: Effective medical management of levodopa-induced dyskinesia (LID) remains an unmet need for patients with Parkinson disease (PD). Changes in opioid transmission in the basal ganglia associated with LID suggest a therapeutic opportunity. Here we determined the impact of modulating both mu and kappa opioid receptor signaling using the mixed agonist/antagonist analgesic nalbuphine in reducing LID and its molecular markers in the nonhuman primate model. METHODS: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated macaques with advanced parkinsonism and reproducible LID received a range of nalbuphine doses or saline subcutaneously as: (1) monotherapy, (2) acute coadministration with levodopa, and (3) chronic coadministration for 1 month. Animals were assessed by blinded examiners for motor disability and LID severity using standardized rating scales. Plasma levodopa levels were determined with and without nalbuphine, and postmortem brain samples were subjected to Western blot analyses. RESULTS: Nalbuphine reduced LID in a dose-dependent manner by 48% (p < 0.001) without compromising the anti-PD effect of levodopa or changing plasma levodopa levels. There was no tolerance to the anti-LID effect of nalbuphine given chronically. Nalbuphine coadministered with levodopa was well tolerated and did not cause sedation. Nalbuphine monotherapy had no effect on motor disability. Striatal tissue analyses showed that nalbuphine cotherapy blocks several molecular correlates of LID, including overexpression of ΔFosB, prodynorphin, dynorphin A, cyclin-dependent kinase 5, and increased phosphorylation of DARPP-32 at threonine-34. INTERPRETATION: Nalbuphine reverses the molecular milieu in the striatum associated with LID and is a safe and effective anti-LID agent in the primate model of PD. These findings support repurposing this analgesic for the treatment of LID.

Transformation of dolutegravir into an ultra-long-acting parenteral prodrug formulation.

Ultra-long-acting integrase strand transfer inhibitors were created by screening a library of monomeric and dimeric dolutegravir (DTG) prodrug nanoformulations. This led to an 18-carbon chain modified ester prodrug nanocrystal (coined NM2DTG) with the potential to sustain yearly dosing. Here, we show that the physiochemical and pharmacokinetic (PK) formulation properties facilitate slow drug release from tissue macrophage depot stores at the muscle injection site and adjacent lymphoid tissues following single parenteral injection. Significant plasma drug levels are recorded up to a year following injection. Tissue sites for prodrug hydrolysis are dependent on nanocrystal dissolution and prodrug release, drug-depot volume, perfusion, and cell-tissue pH. Each affect an extended NM2DTG apparent half-life recorded by PK parameters. The NM2DTG product can impact therapeutic adherence, tolerability, and access of a widely used integrase inhibitor in both resource limited and rich settings to reduce HIV-1 transmission and achieve optimal treatment outcomes.