Case report and literature review: management of Paxlovid (nirmatrelvir/ritonavir)-induced acute tacrolimus toxicity in a patient with systemic lupus erythematosus.

Despite the availability of effective vaccines and treatments for SARS-CoV-2, managing COVID-19 in patients with systemic lupus erythematosus (SLE) remains challenging, particularly considering drug-drug interactions (DDIs). Here, we present a case of DDIs between Tacrolimus (Tac) and nirmatrelvir/ritonavir (NMV/r) in a 32-year-old male with SLE. Following self-administration of NMV/r and resumption of Tac after 5 days, the patient experienced acute nephrotoxicity and neurotoxicity, accompanied by supratherapeutic Tac levels, despite Tac being withheld during NMV/r. The primary cause of this acute toxicity is attributed to ritonavir's inhibitory effect on both CYP3A4 enzymes and P-glycoprotein. Upon admission, Tac was discontinued, and supportive therapies were initiated. Phenytoin, a CYP3A4 inducer, was administered to lower Tac levels under the guidance of clinical pharmacists, effectively alleviating the patient's acute toxic symptoms. The half-life of Tac during the treatment of phenytoin was calculated to be 55.87 h. And no adverse reactions to phenytoin were observed. This case underscores the persistence of enzyme inhibition effects and demonstrates the effectiveness and safety of utilizing CYP3A4 enzyme inducers to mitigate Tac concentrations. Furthermore, it emphasizes the importance of healthcare providers and patients being vigilant about DDIs in Tac recipients. Lastly, it highlights the indispensable role of pharmacist involvement in clinical decision-making and close monitoring in complex clinical scenarios. Although our findings are based on a single case, they align with current knowledge and suggest the potential of individualized combination therapy in managing challenging COVID-19 cases in immunocompromised patients.

Safety and Efficacy of Paxlovid in Pediatric Intensive Care Unit Patients with COVID-19.

INTRODUCTION: Paxlovid (nirmatrelvir/ritonavir) has received endorsement from several guidelines for treating COVID-19 in adults, but its use in children is still uncertain. OBJECTIVES: This study aimed to evaluate the safety and effectiveness of paxlovid in pediatric patients in the pediatric intensive care unit (PICU). METHODS: A retrospective analysis was performed on children with COVID-19. The children who received paxlovid comprised the paxlovid group; otherwise, they were referred to as the control group. RESULTS: A total of 31 children were enrolled, with 12 and 19 participants assigned to the paxlovid and control groups, respectively. Approximately 35% had received vaccination against the novel coronavirus. The control group exhibited a significantly lower mean age in comparison to the paxlovid group (p < 0.001). However, no significant differences were observed between the groups in terms of other baseline data and biochemical indexes at admission. However, on the fifth day of drug administration, the paxlovid group exhibited a statistically significant decrease in temperature compared to the control group (p < 0.05). Additionally, the paxlovid group exhibited a significantly shorter conversion time to negativity for novel coronary genes in the respiratory tract (9.5 days) compared to the control group (16 days, p < 0.05). The administration of paxlovid did not result in any observed adverse reactions. Merely two patients exhibited a transient elevation in liver enzyme levels. CONCLUSION: The application of paxlovid in critically ill pediatric patients with COVID-19 can effectively control symptoms and promote virus clearance, demonstrating efficacy and a relatively low-risk profile.

Characteristics and outcomes of patients with COVID-19 at high risk of disease progression receiving sotrovimab, oral antivirals, or no treatment: a retrospective cohort study.

BACKGROUND: The clinical benefit of coronavirus disease 2019 (COVID-19) treatments against new circulating variants remains unclear. We sought to describe characteristics and clinical outcomes of highest risk patients with COVID-19 receiving early COVID-19 treatments in Scotland. METHODS: Retrospective cohort study of non-hospitalized patients diagnosed with COVID-19 from December 1, 2021-October 25, 2022, using Scottish administrative health data. We included adult patients who met ≥ 1 of the National Health Service highest risk criteria for early COVID-19 treatment and received outpatient treatment with sotrovimab, nirmatrelvir/ritonavir or molnupiravir, or no early COVID-19 treatment. Index date was defined as the earliest of COVID-19 diagnosis or early COVID-19 treatment. Baseline characteristics and acute clinical outcomes in the 28 days following index were reported. Values of ≤ 5 were suppressed. RESULTS: In total, 2548 patients were included (492: sotrovimab, 276: nirmatrelvir/ritonavir, 71: molnupiravir, and 1709: eligible highest risk untreated). Patients aged ≥ 75 years accounted for 6.9% (n = 34/492), 21.0% (n = 58/276), 16.9% (n = 12/71) and 13.2% (n = 225/1709) of the cohorts, respectively. Advanced renal disease was reported in 6.7% (n = 33/492) of sotrovimab-treated and 4.7% (n = 81/1709) of untreated patients, and ≤ 5 nirmatrelvir/ritonavir-treated and molnupiravir-treated patients. All-cause hospitalizations were experienced by 5.3% (n = 25/476) of sotrovimab-treated patients, 6.9% (n = 12/175) of nirmatrelvir/ritonavir-treated patients, ≤ 5 (suppressed number) molnupiravir-treated patients and 13.3% (n = 216/1622) of untreated patients. There were no deaths in the treated cohorts; mortality was 4.3% (n = 70/1622) among untreated patients. CONCLUSIONS: Sotrovimab was often used by patients who were aged < 75 years. Among patients receiving early COVID-19 treatment, proportions of 28-day all-cause hospitalization and death were low.

COVID-19 clinical rebound after treatment with nirmatrelvir/ritonavir.

Background: Nirmatrelvir/ritonavir (NM/r) is a safe and effective oral antiviral therapeutic used for treatment of mild-to-moderate COVID-19. Case reports described a clinical rebound syndrome whereby individuals experience a relapse of symptoms shortly after completing successful treatment. There is a lack of information on frequency of COVID-19 rebound after NM/r in routine clinical care, contributing factors, and clinical outcomes. Methods: We reviewed electronic medical records to verify COVID-19 diagnosis, symptoms, and treatment with NM/r from January-June 2022. We defined COVID-19 clinical rebound as clear improvement in symptoms followed by recurrence or worsening of symptoms within 30 days of a five-day course of NM/r. Results: We studied 268 adults with median age 57 (IQR 47, 68), 80% White race, 85% non-Hispanic ethnicity, 55% female, 80% vaccinated and boosted against SARS-CoV-2, and 68% with any co-morbidity. Sixteen (6.0%) of studied patients were determined to have COVID-19 clinical rebound. The median time from starting NM/r to rebound was 11 days (IQR 9, 13). Notable demographic and clinical factors with higher proportion (not statistically significant) among COVID-19 rebound patients were female sex (75% rebound vs 54.5% no rebound), Black race (12.5% rebound vs 4.9% no rebound), presence of at least one co-morbidity (81.3% rebound vs 67.5% no rebound), and lack of prior SARS-CoV-2 infection (100% rebound vs 92.9% no rebound). Only one patient (6.25%) was hospitalized after COVID-19 rebound. Conclusions: COVID-19 clinical rebound after treatment with NM/r is mild with favorable outcomes and more common than previously reported from real-world clinical care studies.

Oral antivirals for COVID-19 among patients with cancer.

PURPOSE: Immunocompromised individuals, such as those diagnosed with cancer, are at a significantly higher risk for severe illness and mortality when infected with SARS-CoV-2 (COVID-19) than the general population. Two oral antiviral treatments are approved for COVID-19: Paxlovid® (nirmatrelvir/ritonavir) and Lagevrio® (molnupiravir). There is a paucity of data regarding the benefit from these antivirals among immunocompromised patients with cancer, and recent studies have questioned their efficacy among vaccinated patients, even those with risk factors for severe COVID-19. METHODS: We evaluated the efficacy and safety of nirmatrelvir/ritonavir and molnupiravir in preventing severe illness and death using our database of 457 patients with cancer and COVID-19 from Brown University-affiliated hospitals. RESULTS: Sixty-seven patients received nirmatrelvir/ritonavir or molnupiravir and were compared to 45 concurrent controls who received no antiviral treatment despite being eligible to receive it. Administration of nirmatrelvir/ritonavir or molnupiravir was associated with improved survival and lower 90-day all-cause and COVID-19-attributed mortality (p < 0.05) and with lower peak O2 requirements (ordinal odds ratio [OR] 1.52, 95% confidence interval [CI] 0.92-2.56). CONCLUSION: Acknowledging the small size of our sample as a limitation, we concluded that early antiviral treatment might be beneficial to immunocompromised individuals, particularly those with cancer, when infected with SARS-CoV-2. Larger-scale, well-stratified studies are needed in this patient population.

Influence of ensitrelvir or nirmatrelvir/ritonavir on tacrolimus clearance in kidney transplant recipients: a single-center case series.

BACKGROUND: Among the oral antivirals used for treating patients with mild-to-moderate novel coronavirus disease 2019 (COVID-19), nirmatrelvir/ritonavir (NMV/RTV) and ensitrelvir (ESV) are inhibitors of cytochrome P450 (CYP) 3A, and therefore, can cause drug-drug interactions with concomitant medications. Tacrolimus (TAC), a substrate of CYP3A4/5, is administered for a long period to prevent rejection after kidney transplantation. TAC should be discontinued while using NMV/RTV because blood TAC levels significantly increase when these drugs are concomitantly administered. However, the influence of ESV on blood TAC levels has not yet been reported, and the management of TAC doses during the use of ESV remains unclear. CASE PRESENTATION: We experienced three kidney transplant recipients with COVID-19, whose blood trough levels of TAC increased by the concomitant use of NMV/RTV or ESV. In two patients administering NMV/RTV, blood trough levels of TAC increased more than tenfold after combination therapy, whereas in one patient administering ESV, TAC level increased approximately threefold. CONCLUSIONS: These cases suggest that TAC administration should be discontinued during NMV/RTV treatment to maintain blood TAC levels within the therapeutic range, and a reduced TAC dose is sufficient during ESV treatment.

Low Prevalence of Nirmatrelvir-Ritonavir Resistance-Associated Mutations in SARS-CoV-2 Lineages From Botswana.

Background: We evaluated naturally occurring nirmatrelvir-ritonavir (NTV/r) resistance-associated mutations (RAMs) among severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains from Botswana, a country with no NTV/r use to date, in order to recommend the usage of the agent for high-risk patients with coronavirus disease 2019 (COVID-19). Methods: We conducted a retrospective analysis using 5254 complete SARS-CoV-2 sequences from Botswana (September 2020-September 2023). We evaluated the mutational landscape of SARS-CoV-2 3-Chymotrypsin-like protease (3CLpro) relative to the highlighted list of RAMs granted Food and Drug Administration Emergency Use Authorization in 2023. Results: The sequenced 5254 samples included Beta variants of concerns (VOCs; n = 323), Delta VOCs (n = 1314), and Omicron VOCs (n = 3354). Overall, 77.8% of the sequences exhibited at least 1 polymorphism within 76/306 amino acid positions in the nsp5 gene. NTV/rRAMs were identified in 34/5254 (0.65%; 95% CI, 0.43%-0.87%) and occurred at 5 distinct positions. Among the NTV/r RAMS detected, A191V was the most prevalent (24/34; 70.6%). Notably, T21I mutation had a prevalence of 20.6% (7/34) and coexisted with either K90R (n = 3) polymorphism in Beta sequences with RAMs or P132H (n = 3) polymorphism for Omicron sequences with RAMs. Other NTV/r RAMs detected included P108S, with a prevalence of 5.88% (2/34), and L50F, with a prevalence of 2.94% (1/34). NTV/r RAMs were significantly higher (P < .001) in Delta (24/35) compared with Beta (4/34) and Omicron (6/34) sequences. Conclusions: The frequency of NTV/r RAMs in Botswana was low. Higher rates were observed in Delta VOCs compared to Omicron and Beta VOCs. As NTV/r use expands globally, continuous surveillance for drug-resistant variants is essential, given the RAMs identified in our study.

Antiviral Use in Mild-to-Moderate SARS-CoV-2 Infections during the Omicron Wave in Geriatric Patients.

(1) Background: Geriatric patients are at high risk of complications of Coronavirus disease-2019 (COVID-19) and are good candidates for antiviral drugs. (2) Methods: A retrospective study of electronic health records (EHRs) aiming to describe antiviral (nirmatrelvir and ritonavir (nirmatrelvir/r) or remdesivir) use, drug-drug interactions (DDIs) and adverse drug reactions (ADRs) in elderly patients (75 and over), hospitalized with mild-to-moderate COVID-19 between July 2022 and June 2023. (3) Results: Out of 491 patients (mean age: 86.9 years), 180 (36.7%) received nirmatrelvir/r, 78 (15.9%) received remdesivir, and 233 (47.4%) received no antiviral therapy. No association was found between the choice of antiviral and the demographic or medical data. No serious ADR was observed. Nirmatrelvir/r dosage adjustment was inadequate in 65% of patients with renal impairment. In total, 128 patients (71%) on nirmatrelvir/r had potential pharmacokinetic DDIs, with 43 resulting in a possibly related ADR. In the remdesivir group, pharmacodynamic DDIs were more frequent, with QTc prolongation risk in 56 patients (72%). Only 20 patients underwent follow-up ECG, revealing QTc prolongation in 4. (4) Conclusions: There is an underutilization of antivirals despite their justified indications. Nirmatrelvir/r dosage was rarely adjusted to renal function. Dose adjustments and closer monitoring are needed due to the high risk of drug interactions.

Azvudine versus Paxlovid in COVID-19: A systematic review and meta-analysis.

This systematic review and meta-analysis aimed to compare the effectiveness and safety of azvudine versus nirmatrelvir/ritonavir (Paxlovid) in treating coronavirus disease 2019 (COVID-19). The researchers conducted searches on PubMed, Cochrane Library, Web of Science, medRxiv, and Google Scholar until January 2024. The Cochrane risk of bias tool was utilised to evaluate the quality of the included studies, and data analysis was performed using Comprehensive Meta-Analysis software. Thirteen studies, including 4949 patients, were analysed. The meta-analysis results showed no significant difference between the azvudine and Paxlovid groups in terms of mortality rate (odds rate [OR] = 0.84, 95% confidence interval [CI]: 0.59-1.21), negative polymerase chain reaction (PCR) conversion time (standard mean difference [SMD] = 1.52, 95% CI: -1.07-4.11), and hospital stay (SMD = -0.39, 95% CI: -1.12-0.33). However, a significant difference was observed between the two groups in terms of intensive care unit admission (OR = 0.42, 95% CI: 0.23-0.75) and the need for mechanical ventilation (OR = 0.61, 95% CI: 0.44-0.86) in favour of azvudine. The incidence of adverse events in the azvudine group was significantly lower (OR = 0.66, 95% CI: 0.43-0.99). The certainty of evidence was rated as low and moderate. Azvudine and Paxlovid demonstrated similar effectiveness in reducing mortality rates, negative PCR conversion time and hospital stay. However, azvudine showed better effectiveness in improving other outcomes. Regarding the level of certainty of evidence, further research is needed to validate or challenge these results.

Identifying Veterans Who Benefit From Nirmatrelvir-Ritonavir: A Target Trial Emulation.

BACKGROUND: Nirmatrelvir-ritonavir is recommended for persons at risk for severe coronavirus disease 2019 (COVID-19) but remains underutilized. Information on which eligible groups are likely to benefit from treatment is needed. METHODS: We conducted a target trial emulation study in the Veterans Health Administration comparing nirmatrelvir-ritonavir treated versus matched untreated veterans at risk for severe COVID-19 who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from April 2022 through March 2023. We measured incidence of any hospitalization or all-cause mortality at 30 days. Outcomes were measured for the entire cohort, as well as among subgroups defined by 30-day risk of death or hospitalization, estimated using an ensemble risk prediction model. RESULTS: Participants were 87% male with median age 66 years and 16% unvaccinated. Compared with matched untreated participants, those treated with nirmatrelvir-ritonavir (n = 24 205) had a lower 30-day risk for hospitalization (1.80% vs 2.30%; risk difference [RD], -0.50% points [95% confidence interval {CI}: -.69 to -.35]) and death (0.11% vs 0.30%; RD, -0.20 [95% CI: -.24 to -.13]). The greatest reductions in combined hospitalization or death were observed in the highest risk quartile (RD -2.85 [95% CI: -3.94 to -1.76]), immunocompromised persons (RD -1.91 [95% CI: -3.09 to -.74]), and persons aged ≥75 years (RD -1.16 [95% CI: -1.73 to -.59]). No reductions were observed in the 2 lowest risk quartiles or persons younger than 65 years. CONCLUSIONS: Nirmatrelvir-ritonavir was effective in reducing 30-day hospitalization and death in older veterans, those at highest predicted risk for severe outcomes, and immunocompromised groups. Benefit was not observed in younger veterans or groups at lower predicted risk for hospitalization and death.

The effect of oral antiviral therapy for COVID-19 in managing non-hospitalized patients with lung cancer.

BACKGROUNDS: The effectiveness of oral antiviral therapy including nirmatrelvir plus ritonavir and molnupiravir in managing COVID-19 among individuals with pre-existing lung cancer was unclear. Therefore, this study was conducted to evaluate the usefulness of antiviral agents in the management of COVID-19 among patients with lung cancer. METHODS: Utilizing data from the TriNetX - a global health research network, a retrospective cohort study was conducted involving 2484 patients diagnosed with both lung cancer and COVID-19. Propensity score matching (PSM) was employed to create well-balanced cohorts. The study assessed the primary outcome of all-cause hospitalization or mortality within a 30-day follow-up. RESULTS: After PSM, the oral antiviral group exhibited a significantly lower risk of the primary composite outcome compared to the control group (6.1 % vs. 9.9 %; HR: 0.60; 95 % CI: 0.45-0.80). This association was consistent across various subgroups according to age, sex, vaccine status, type of oral antiviral agent, and lung cancer characteristics. Additionally, the oral antiviral group showed a lower risk of all-cause hospitalization (HR: 0.73; 95 % CI: 0.54-0.99) and a significantly lower risk of mortality (HR: 0.16; 95 % CI: 0.06-0.41). CONCLUSION: The study suggests a favorable impact of oral antiviral therapy on the outcomes of COVID-19 in individuals with lung cancer and support the potential utility of oral antiviral agents in improving outcomes in this vulnerable population.

Nirmatrelvir and ritonavir for inpatients with severe or critical COVID-19 beyond five days of symptom onset: a propensity score-matched, multicenter, retrospective cohort study.

BACKGROUND: There is an urgent need for therapeutic strategies for inpatients with severe or critical COVID-19. The evaluation of the clinical benefits of nirmatrelvir and ritonavir (Nmr/r) for these patients beyond five days of symptom onset is insufficient. METHODS: A new propensity score-matched cohort was constructed by using multicenter data from 6695 adult inpatients with COVID-19 from December 2022 to February 2023 in China after the epidemic control measures were lifted across the country. The severity of disease of the inpatients was based on the tenth trial edition of the Guidelines on the Diagnosis and Treatment of COVID-19 in China. The symptom onset of 1870 enrolled severe or critical inpatients was beyond five days, and they received either Nmr/r plus standard treatment or only standard care. The ratio of patients whose SOFA score improved more than 2 points, crucial respiratory endpoints, changes in inflammatory markers, safety on the seventh day following the initiation of Nmr/r treatment, and length of hospital stay were evaluated. RESULTS: In the Nmr/r group, on Day 7, the number of patients with an improvement in SOFA score ≥ 2 was much greater than that in the standard treatment group (P = 0.024) without a significant decrease in glomerular filtration rate (P = 0.815). Additionally, the rate of new intubation was lower (P = 0.004) and the no intubation days were higher (P = 0.003) in the first 7 days in the Nmr/r group. Other clinical benefits were limited. CONCLUSIONS: Our study may provide new insight that inpatients with severe or critical COVID-19 beyond five days of symptom onset benefit from Nmr/r. Future studies, particularly randomized controlled trials, are necessary to verify the above findings.

Early use of oral antiviral drugs and the risk of post COVID-19 syndrome: A systematic review and network meta-analysis.

OBJECTIVES: This study aimed to determine the association of early use of oral antiviral drugs (including nirmatrelvir-ritonavir and molnupiravir) with the risk of post COVID-19 condition (PCC) and compare the possible efficacy of nirmatrelvir-ritonavir and molnupiravir. METHODS: PubMed, Web of Science, Embase, Cochrane, MedRxiv, and Psycinfo were searched from inception until November 1, 2023. We included studies that assessed the effect of oral antiviral drugs on the incidence of PCC. Pairwise and network meta-analyses were conducted using a random-effects model. Risk ratios (RRs) for oral antiviral drugs were calculated with a confidence interval (CI). RESULTS: Nine observational studies containing 866,066 patients were included. Nirmatrelvir-ritonavir and molnupiravir were evaluated in eight and two studies respectively, with both drugs evaluated in one study. Pair-wise meta-analysis showed that early oral antiviral drugs reduced PCC risk (RR 0.77, 95% CI 0.68-0.88). Network meta-analysis showed that nirmatrelvir-ritonavir may perform better than molnupiravir (surface under the cumulative ranking curve: 95.5% vs. 31.6%) at reducing PCC risk. CONCLUSIONS: Early use of oral antiviral drugs may potentially protect against developing PCC in non-hospitalized patients with COVID-19. These findings support the standardized administration of oral antiviral drugs in patients during the acute phase of COVID-19 according to the guidelines.

New variants of COVID-19 (XBB.1.5 and XBB.1.16, the "Arcturus"): A review of highly questioned concerns, a brief comparison between different peaks in the COVID-19 pandemic, with a focused systematic review on expert recommendations for prevention, vaccination, and treatment measures in the general population and at-risk groups.

INTRODUCTION: The COVID-19 pandemic has taken many forms and continues to evolve, now around the Omicron wave, raising concerns over the globe. With COVID-19 being declared no longer a "public health emergency of international concern (PHEIC)," the COVID pandemic is still far from over, as new Omicron subvariants of interest and concern have risen since January of 2023. Mainly with the XBB.1.5 and XBB.1.16 subvariants, the pandemic is still very much "alive" and "breathing." METHODS: This review consists of five highly concerning questions about the current state of the COVID Omicron peak. We searched four main online databases to answer the first four questions. For the last one, we performed a systematic review of the literature, with keywords "Omicron," "Guidelines," and "Recommendations." RESULTS: A total of 31 articles were included. The main symptoms of the current Omicron wave include a characteristically high fever, coughing, conjunctivitis (with itching eyes), sore throat, runny nose, congestion, fatigue, body ache, and headache. The median incubation period of the symptoms is shorter than the previous peaks. Vaccination against COVID can still be considered effective for the new subvariants. CONCLUSION: Guidelines recommend continuation of personal protective measures, third and fourth dose boosters, along with administration of bivalent messenger RNA vaccine boosters. The consensus antiviral treatment is combination therapy using Nirmatrelvir and Ritonavir, and the consensus for pre-exposure prophylaxis is Tixagevimab and Cilgavimab combination. We hope the present paper raises awareness for the continuing presence of COVID and ways to lower the risks, especially for at-risk groups.

Evaluation of Sources of Drug Interaction Information for Nirmatrelvir/ritonavir.

The Japanese package insert (J-PI) for nirmatrelvir/ritonavir (N/r) (specially approved pharmaceutical) includes numerous warnings about drug interactions. However, discrepancies in the information on drug interaction are reported between J-PI and foreign databases. This study aimed to evaluate various information sources on N/r drug interactions. We categorized and compared information on N/r drug interactions from the J-PI, prescribing information from foreign regulatory agencies, guidance from the National Institutes of Health and University Health Network, the Ontario coronavirus disease 2019 (COVID-19) Science Advisory Table, University of Liverpool, Lexicomp, and the Japanese Society of Pharmaceutical Health Care and Sciences (JSPHCS). We assessed information quantity, missing data in J-PI, predicted change of the area under the blood concentration-time curve (AUC) for nirmatrelvir or co-administered drugs, and the information source consistency. From these information sources, we compiled a dataset with 115 contraindications and 203 precautions for N/r co-administration, and 51 contraindications are missing in J-PI. Among them, at least 12 drugs have large predicted AUC changes with N/r (AUC ≥5-fold or <1/5 of the baseline value). Nine of these 12 drugs are included as contraindications in Lexicomp and the JSPHCS. The consistency among the information sources is low. Information in the J-PI alone may be insufficient and Lexicomp or the JSPHCS guidelines should be useful because of their large amounts of information and wide coverage of drugs with large AUC changes. Due to low source consistency, multiple sources are needed for clinical management.

Clinical Outcome and 7-Day Virological Clearance in High-Risk Patients with Mild-Moderate COVID-19 Treated with Molnupiravir, Nirmatrelvir/Ritonavir, or Remdesivir.

INTRODUCTION: We compared the effectiveness and virological clearance (VC) at day 7 (T7) post-treatment with molnupiravir, nirmatrelvir/ritonavir, and remdesivir in SARS-CoV-2-infected patients at high risk (HR) for clinical progression. METHODS: We conducted a retrospective study enrolling HR patients with mild-to-moderate COVID-19 (Jan-Oct 2022) treated with nirmatrelvir/ritonavir or molnupiravir or 3 days of remdesivir. We investigated clinical recovery at T7 (resolution of symptoms for ≥ 72 h or all-cause death), VC at T7 (PCR/antigenic negative nasopharyngeal swab), and median time to VC (days from symptom onset to the first negative swab). Factors associated with VC were investigated by logistic regression. RESULTS: In the study, 92/376 (43.8%) patients received molnupiravir, 150/376 (24.7%) nirmatrelvir/ritonavir, and 134/376 (31.5%) remdesivir. Forty-nine (13%) patients were unvaccinated or incompletely vaccinated. Patients treated with nirmatrelvir/ritonavir were younger and presented immunodeficiencies more frequently; remdesivir was used more commonly in patients hospitalized for other diseases. A high proportion of patients obtained clinical recovery without differences among the therapies (97.5% for molnupiravir, 98.3% for nirmatrelvir/ritonavir, and 93.6% for remdesivir); 12 (3.7%) patients died. Nirmatrelvir/ritonavir was associated with a higher proportion of T7 VC and a shorter time to VC compared to molnupiravir/remdesivir, also after adjustment for age and immunodeficiency (AOR 0.445 RDV vs. NMV-r, 95% CI 0.240-0.826, p = 0.010; AOR 0.222 MNP vs. NMV-r, 95% CI 0.105-0.472, p < 0.001). CONCLUSIONS: SARS-COV-2 antiviral treatments are an excellent therapeutic strategy in HR patients. Nirmatrelvir/ritonavir showed a higher proportion of VC as early as 7 days after treatment, confirming its likely superiority in indirect comparisons.

Nirmatrelvir-ritonavir, molnupiravir, and a 3-day course of remdesivir are antiviral therapies recommended in patients with a mild-to-moderate COVID-19 disease at high risk of clinical progression. Randomized controlled trials and observational studies have shown their efficacy in reducing all-cause mortality and clinical progression. Few data are available about a direct comparison among the three drugs; furthermore, the possible role of nirmatrelvir-ritonavir in increasing viral clearance and in reducing the duration of viral shedding needs to be further elucidated. We thus investigated the effectiveness, safety, and virological clearance 7 days after treatment with these three antivirals in our retrospective cohort. We included in the analysis patients that have received these treatments from January 2022 and October 2022; we observed that patients receiving nirmatrelvir-ritonavir displayed a shorter median time from symptoms' onset to virological clearance and a higher proportion of virological clearance at day 7, also after adjustment for possible confounders, compared to molnupiravir and remdesivir. Our data might help in understanding which COVID-19 patients may benefit mostly from antiviral therapies and in the choice of antiviral therapy.

Influence of Solvent Selection on the Crystallizability and Polymorphic Selectivity Associated with the Formation of the "Disappeared" Form I Polymorph of Ritonavir.

The comparative crystallizability and polymorphic selectivity of ritonavir, a novel protease inhibitor for the treatment of acquired immune-deficiency syndrome, as a function of solvent selection are examined through an integrated and self-consistent experimental and computational molecular modeling study. Recrystallization at high supersaturation by rapid cooling at 283.15 K is found to produce the metastable "disappeared" polymorphic form I from acetone, ethyl acetate, acetonitrile, and toluene solutions in contrast to ethanol which produces the stable form II. Concomitant crystallization of the other known solid forms is not found under these conditions. Isothermal crystallization studies using turbidometric detection based upon classical nucleation theory reveal that, for an equal induction time, the required driving force needed to initiate solution nucleation decreases with solubility in the order of ethanol, acetone, acetonitrile, ethyl acetate, and toluene consistent with the expected desolvation behavior predicted from the calculated solute solvation free energies. Molecular dynamics simulations of the molecular and intermolecular chemistry reveal the presence of conformational interplay between intramolecular and intermolecular interactions within the solution phase. These encompass the solvent-dependent formation of intramolecular O-H...O hydrogen bonding between the hydroxyl and carbamate groups coupled with differing conformations of the hydroxyl's shielding phenyl groups. These conformational preferences and their relative interaction propensities, as a function of solvent selection, may play a rate-limiting role in the crystallization behavior by not only inhibiting to different degrees the nucleation process but also restricting the assembly of the optimal intermolecular hydrogen bonding network needed for the formation of the stable form II polymorph.

Simultaneous measurement of COVID-19 treatment drugs (nirmatrelvir and ritonavir) in rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study.

PAXLOVID™ (Co-packaging of Nirmatrelvir with Ritonavir) has been approved for the treatment of Coronavirus Disease 2019 (COVID-19). The goal of the experiment was to create an accurate and straightforward analytical method using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) to simultaneously quantify nirmatrelvir and ritonavir in rat plasma, and to investigate the pharmacokinetic profiles of these drugs in rats. After protein precipitation using acetonitrile, nirmatrelvir, ritonavir, and the internal standard (IS) lopinavir were separated using ultra performance liquid chromatography (UPLC). This separation was achieved with a mobile phase composed of acetonitrile and an aqueous solution of 0.1% formic acid, using a reversed-phase column with a binary gradient elution. Using multiple reaction monitoring (MRM) technology, the analytes were detected in the positive electrospray ionization mode. Favorable linearity was observed in the calibration range of 2.0-10000 ng/mL for nirmatrelvir and 1.0-5000 ng/mL for ritonavir, respectively, within plasma samples. The lower limits of quantification (LLOQ) attained were 2.0 ng/mL for nirmatrelvir and 1.0 ng/mL for ritonavir, respectively. Both drugs demonstrated inter-day and intra-day precision below 15%, with accuracies ranging from -7.6% to 13.2%. Analytes were extracted with recoveries higher than 90.7% and without significant matrix effects. Likewise, the stability was found to meet the requirements of the analytical method under different conditions. This UPLC-MS/MS method, characterized by enabling accurate and precise quantification of nirmatrelvir and ritonavir in plasma, was effectively utilized for in vivo pharmacokinetic studies in rats.

Antiviral combination regimens as rescue therapy in immunocompromised hosts with persistent COVID-19.

The management of severe/prolonged SARS-CoV-2 infections in immunocompromised hosts is still challenging. We describe nine patients with hematologic malignancies with a history of unsuccessful SARS-CoV-2 treatment receiving antiviral combination treatment for persistent infection at a tertiary hospital in central Italy (University Hospital of Careggi, Florence). Combination treatments consisted of nirmatrelvir/ritonavir plus molnupiravir (n = 4), nirmatrelvir/ritonavir plus remdesivir (n = 4) or remdesivir plus molnupiravir (n = 1) for 10 days, in some cases associated with sotrovimab. Combinations were generally well tolerated. One patient obtained viral clearance but died due to the underlying disease. In eight cases, clinical and virological success was confirmed by radiological follow-up. Antivirals combination is likely to become a mainstay in the future management of COVID-19 among immunocompromised patients, but knowledge in this field is still very limited and prospective studies on larger cohorts are urgently warranted.