The effects of nirmatrelvir/ritonavir on tacrolimus levels in lung transplant recipients: A single-center study

BACKGROUND

Lung transplant recipients (LTRs) have a higher risk of hospitalization and mortality due to COVID-19 compared with the immunocompetent population. The use of nirmatrelvir/ritonavir (NR), an effective oral treatment for COVID-19, is quite challenging due to its potent drug-drug interactions with immunosuppressants and azole antifungals. As there are few clinical reports of the use of NR in LTRs, we measured tacrolimus levels in patients receiving NR in our hospital to improve safety when prescribing NR.

METHODS

In total, 48 adult LTRs who received NR between November 19, 2022, and January 19, 2023, at China-Japan Friendship Hospital were retrospectively included and followed for 20 days after initiating NR. Tacrolimus was held at least 12 h before initiating NR and re-administered based on the trough levels after completing NR treatment. All concomitant medications, drug concentrations, laboratory results, and genotypes were recorded and analyzed.

RESULTS

Most patients showed stable tacrolimus trough levels despite high individual variability. Four patients exhibited supratherapeutic trough levels of tacrolimus (more than 15 ng/mL). Two patients who received 0.5 mg of tacrolimus during NR treatment had trough levels below 3.0 ng/mL. In addition, we found that in 13 patients, the trough levels were 130% of baseline after cessation of tacrolimus, and logistic regression revealed that increased trough level was significantly associated with age more than 60 years.

CONCLUSIONS

NR can be safely used in LTRs with close monitoring of tacrolimus levels and appropriate dose adjustments. However, more attention should be paid to elderly patients, as NR may more severely affect their drug metabolism. Due to the limited sample size, further studies are needed to guide the optimal use of tacrolimus following treatment with NR and explore the risk factors significantly affecting the interactions between NR and tacrolimus.

Nonsteroidal anti-inflammatory drugs (NSAIDs) and nucleotide analog GS-441524 conjugates with potent in vivo efficacy against coronaviruses

Coronaviruses (CoVs) infect a broad range of hosts, including humans and various animals, with a tendency to cross the species barrier, causing severe harm to human society and fostering the need for effective anti-coronaviral drugs. GS-441524 is a broad-spectrum antiviral nucleoside with potent anti-CoVs activities. However, its application is limited by poor oral bioavailability. Herein, we designed and synthesized several conjugates via covalently binding NSAIDs to 5'-OH of GS-441524 through ester bonds. The ibuprofen conjugate, ATV041, exhibited potent in vitro anti-coronaviral efficacy against four zoonotic coronaviruses in the alpha- and beta-genera. Oral-dosed ATV041 resulted in favorable bioavailability and rapid tissue distribution of GS-441524 and ibuprofen. In MHV-A59 infected mice, ATV041 dose-dependently decreased viral RNA replication and significantly reduced the proinflammatory cytokines in the liver and the lung at 3 dpi. As a result, the MHV-A59-induced lung and liver inflammatory injury was significantly alleviated. Taken together, this work provides a novel drug conjugate strategy to improve oral PK and offers a potent anti-coronaviral lead compound for further studies.

Efficacy and Safety of Favipiravir in Moderate COVID-19 Pneumonia Patients without Oxygen Therapy: A Randomized, Phase III Clinical Trial

Introduction

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19), is an enveloped, single-stranded RNA virus. Favipiravir is an orally administrable antiviral drug whose mechanism of action is to selectively inhibit RNA-dependent RNA polymerase. A preliminary trial in COVID-19 patients reported significant improvements across a multitude of clinical parameters, but these findings have not been confirmed in an adequate well-controlled trial. We conducted a randomized, single-blind, placebo-controlled Phase III trial assessing the efficacy and safety of favipiravir in patients with moderate pneumonia not requiring oxygen therapy.

Methods

COVID-19 patients with moderate pneumonia (SpO₂ ≥ 94%) within 10 days of onset of fever (temperature ≥ 37.5 °C) were assigned to receive either placebo or favipiravir (1800 mg twice a day on Day 1, followed by 800 mg twice a day for up to 13 days) in a ratio of 1:2. An adaptive design was used to re-estimate the sample size. The primary endpoint was a composite outcome defined as the time to improvement in temperature, oxygen saturation levels (SpO₂), and findings on chest imaging, and recovery to SARS-CoV-2-negative. This endpoint was re-examined by the Central Committee under blinded conditions.

Results

A total of 156 patients were randomized. The median time of the primary endpoint was 11.9 days in the favipiravir group and 14.7 days in the placebo group, with a significant difference (p = 0.0136). Favipiravir-treated patients with known risk factors such as obesity or coexisting conditions provided better effects. Furthermore, patients with early-onset in the favipiravir group showed higher odds ratio. No deaths were documented. Although adverse events in the favipiravir group were predominantly transient, the incidence was significantly higher.

Conclusions

The results suggested favipiravir may be one of options for moderate COVID-19 pneumonia treatment. However, the risk of adverse events, including hyperuricemia, should be carefully considered.

Trial registration

Clinicaltrials.jp number: JapicCTI-205238.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00517-4.