Recent Publications

Doravirine is a non-nucleoside reverse transcriptase inhibitor indicated for the treatment of human immunodeficiency virus (HIV)-1 infection. This phase 1 study in healthy adults investigated the pharmacokinetics, safety and tolerability of long-acting parenteral (LAP) microsuspension formulations of doravirine administered as an intramuscular (IM) injection.

Although effective, some oral pre-exposure prophylaxis (PrEP) users face barriers to adherence using daily pills, which could be reduced by long-acting formulations. Long-acting cabotegravir (CAB LA) is a potential new injectable formulation for HIV PrEP being tested in Phase III trials.

Chronic hepatitis C virus (HCV) infection is a leading cause of cirrhosis worldwide and kills more Americans than 59 other infections, including HIV and tuberculosis, combined. While direct-acting antiviral (DAA) treatments are effective, limited uptake of therapy, particularly in high-risk groups, remains a substantial barrier to eliminating HCV. We developed a long-acting DAA system (LA-DAAS) capable of prolonged dosing and explored its cost-effectiveness. We designed a retrievable coil-shaped LA-DAAS compatible with nasogastric tube administration and the capacity to encapsulate and release gram levels of drugs while resident in the stomach. We formulated DAAs in drug-polymer pills and studied the release kinetics for 1 mo in vitro and in vivo in a swine model. The LA-DAAS was equipped with ethanol and temperature sensors linked via Bluetooth to a phone application to provide patient engagement. 

The first long-acting formulations of HIV drugs are undergoing regulatory review for use in maintenance of viral suppression in people with HIV. Although these novel drug formulations could contribute greatly to HIV treatment and prevention efforts, their lack of activity against hepatitis B virus (HBV) could limit their global impact, particularly in populations with high burdens of both HIV and HBV.

Long-acting (LA) administration using a subcutaneous (SC) implant presents opportunities to simplify administration of antiretroviral drugs, improve pharmacological (PK) profile and overcome sub-optimal adherence associated with daily oral formulations. Tenofovir alafenamide (TAF) is a highly potent nucleoside reverse transcriptase inhibitor (NRTI) and an attractive agent for LA delivery, with a high potency and long intracellular half-life. The aim of this study was to predict minimum TAF doses required to achieve concentrations effective for HIV pre-exposure prophylaxis (PrEP). Daily drug-release requirements were then ascertained by averaging across the dosing interval.

TLC-ART101 is a long-acting triple-HIV drug combination of lopinavir-ritonavir-tenofovir in one nanosuspension intended for subcutaneous injection. After a single TLC-ART 101 administration in nonhuman primates, drug concentrations in both plasma and HIV-target lymph node mononuclear cells were sustained for 2 weeks. Nevertheless, the mechanisms leading to the targeted long-acting pharmacokinetics remain elusive. Therefore, an intravenous study of TLC-ART 101 in nonhuman primates was conducted to elucidate the degree of association of drugs in vivo, estimate subcutaneous bioavailability, and refine a mechanism-based pharmacokinetic (MBPK2) model. The MBPK2 model considers TLC-ART 101 systemic drug clearances, nanoparticle-associated/dissociated species, more detailed mechanisms of lymphatic first-pass retention of associated-drugs after subcutaneous administrations, and the prediction of drug concentration time-courses in lymph node mononuclear cells. 

With long-acting injectable antiretroviral therapy likely to be a treatment option for people living with HIV (PLWH), it is critical to assess its acceptability among potential end-users. Based on formative qualitative work and our own ongoing development of targeted long-acting products in nanosuspension formulations, we created eight hypothetical medication scenarios varying along six dichotomous attributes: administration location (home versus [vs.] clinic), dosing frequency (every 2 weeks vs. 1 week), injections per dose (one vs. two), injection pain (mild vs. moderate), injection site reaction (mild vs. moderate), and effectiveness (better vs. same as pills). PLWH from three outpatient care clinics in Seattle, WA and Riverside, CA rated acceptability (i.e., willingness to try each hypothetical medication) from 0 (very unlikely) to 100 (very likely). In conjoint analyses, we examined level and correlates of acceptability, the impact of each attribute on overall acceptability, and moderators of this effect. 

Early diagnosis along with new drugs targeted to cancer receptors and immunocheckpoints have improved breast cancer survival. However, full remission remains elusive for metastatic breast cancer due to dose-limiting toxicities of heavily used, highly potent drug combinations such as gemcitabine and paclitaxel. Therefore, novel strategies that lower the effective dose and improve safety margins could enhance the effect of these drug combinations. To this end, we developed and evaluated a novel drug combination of gemcitabine and paclitaxel (GT). Leveraging a simple and scalable drug-combination nanoparticle platform (DcNP), we successfully prepared an injectable GT combination in DcNP (GT DcNP). 

Adherence to antiretroviral therapy (ART) is imperative for viral suppression and reducing HIV transmission, but many people living with HIV report difficultly sustaining long-term adherence. Long-acting injectable (LAI) ART has the potential to transform HIV treatment and prevention. However, little LAI ART-related behavioral research has occurred among women, particularly outside of clinical trials.

As a long-acting formulation of the non-nucleoside reverse transcriptase inhibitor rilpivirine (RPV LA) has been proposed for use as pre-exposure prophylaxis (PrEP) and the prevalence of transmitted RPV-resistant viruses can be relatively high, we evaluated the efficacy of RPV LA to inhibit vaginal transmission of RPV-resistant HIV-1 in humanized mice.