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.

Disease-modifying therapies in systemic lupus erythematosus for extrarenal manifestations

Our 2022 published working definition of disease modification in systemic lupus erythematosus (SLE) was 'minimising disease activity with the fewest treatment-associated toxicities and slowing or preventing organ damage progression'. The objective of this review was to classify current SLE treatments according to the proposed non-renal disease modification criteria excluding toxicities. Based on a review of select clinical trial (n=32) and observational study (n=54) publications for 14 SLE medications across different therapeutic classes, and the authors' clinical experience, we evaluated disease modification potential as per the proposed framework at three time points. Specific criteria used to determine disease modification potential included a drug's capacity to reduce: (1) non-renal disease activity, (2) severe flares, (3) use of steroids/immunosuppressants and (4) organ damage accrual. Criteria 1-3 were assessed at 1 year and 2-5 years and, when positive, were considered evidence for disease modification potential; criterion 4 was used to confirm disease modification at >5 years. Each treatment received one of four mutually exclusive designations at each time point: (a) criterion met, (b) indications of criterion met despite insufficient evidence in the literature, (c) inconclusive and (d) no available supportive data. This review excludes an assessment of potential toxicities. Eight of the 14 SLE treatments met ≥1 disease modification criteria up to year 5. Hydroxychloroquine improved overall survival at >5 years, suggesting long-term disease modification, but no data on specific organ systems were reported. Belimumab was the only treatment to meet all criteria. Belimumab and hydroxychloroquine met disease modification definitions across three time points. Evidence for other SLE therapies was incomplete, particularly at >5 years. Future studies are warranted for other treatments to meet the disease modification criteria. We discuss challenges to classification and possible updates to our published criteria.

Comparison of efficacy of continuous mycophenolate mofetil with sequential cyclophosphamide and tacrolimus as maintenance therapy for lupus nephritis

OBJECTIVES

To evaluate the renal response to mycophenolate mofetil (MMF) as maintenance therapy for lupus nephritis (LN) in Japanese patients, we compared the efficacy of MMF and the sequential use of monthly intravenous cyclophosphamide (IVCY) followed by tacrolimus (TAC).

METHODS

We examined 14 patients with LN who were treated with continuous MMF as induction and maintenance therapies (MMF group) and 10 patients with LN who received monthly IVCY as induction therapy followed by maintenance therapy with TAC (IVCY-TAC group). We assessed the therapeutic effects of each treatment regimen on renal manifestations and serological findings over a 36-month period after treatment initiation.

RESULTS

Mean urine protein-to-creatinine ratios in the MMF and IVCY-TAC groups significantly decreased from 2.75 to 0.11 g/gCr and from 3.26 to 0.22 g/gCr, respectively. Significant improvements in serum immunological variables (serum complement C3 or C4 levels and the anti-double-stranded DNA antibody titer) and reductions in the SLE disease activity index and daily prednisolone dosages were observed in both groups during induction therapy and were maintained during maintenance therapy. Efficacy was similar between the MMF and IVCY-TAC groups.

CONCLUSION

MMF has potential as an effective treatment for renal manifestations in Japanese patients throughout induction and maintenance therapies for LN, as an alternative to conventional IVCY-TAC therapy, and as a glucocorticoid-sparing agent.

Dosage optimization of tacrolimus based on the glucocorticoid dose and pharmacogenetics in adult patients with systemic lupus erythematosus

BACKGROUND

The purpose of the study was to develop a genotype-incorporated population pharmacokinetic (PPK) model of tacrolimus (TAC) in adults with systemic lupus erythematosus (SLE) to investigate the factors influencing TAC pharmacokinetics and to develop an individualized dosing regimen based on the model. In addition, a non-genotype-incorporated model was also established to assess its predictive performance compared to the genotype-incorporated model.

METHODS

A total of 365 trough concentrations from 133 adult SLE patients treated with TAC were collected to develop a genotype-incorporated PPK model and a non-genotype-incorporated PPK model of TAC using a nonlinear mixed-effects model (NONMEM). External validation of the two models was performed using data from an additional 29 patients. Goodness-of-fit diagnostic plots, bootstrap method, and normalized predictive distribution error test were used to validate the predictive performance and stability of the final models. The goodness-of-fit of the two final models was compared using the Akaike information criterion (AIC). The dosing regimen was optimized using Monte Carlo simulations based on the developed optimal model.

RESULTS

The typical value of the apparent clearance (CL/F) of TAC estimated in the final genotype-incorporated model was 14.3 L h-1 with inter-individual variability of 27.6%. CYP3A5 polymorphism and coadministered medication were significant factors affecting TAC-CL/F. CYP3A5 rs776746 GG genotype carriers had only 77.3% of the TAC-CL/F of AA or AG genotype carriers. Omeprazole reduced TAC-CL/F by 3.7 L h-1 when combined with TAC, while TAC-CL/F increased nonlinearly as glucocorticoid dose increased. Similar findings were demonstrated in the non-genotype-incorporated PPK model. Comparing these two models, the genotype-incorporated PPK model was superior to the non-genotype-incorporated PPK model (AIC = 643.19 vs. 657.425). Monte Carlo simulation based on the genotype-incorporated PPK model indicated that CYP3A5 rs776746 AA or AG genotype carriers required a 1/2-1 fold higher dose of TAC than GG genotype carriers to achieve the target concentration. And as the daily dose of prednisone increases, the dose of TAC required to reach the target concentration increases appropriately.

CONCLUSIONS

We developed the first pharmacogenetic-based PPK model of TAC in adult patients with SLE and proposed a dosing regimen based on glucocorticoid dose and CYP3A5 genotype according to the model, which could facilitate individualized dosing for TAC.

Safety and efficacy of switching immunosuppressive drugs for maintenance treatment in patients with systemic lupus erythematosus: A retrospective cohort study

OBJECTIVES

We aim to clarify the efficacy and safety of switching immunosuppressive drugs and to identify the predictive factors for treatment failure after switching in patients with systemic lupus erythematosus (SLE).

METHODS

We retrospectively evaluated patients with SLE who switched immunosuppressive drugs for any reason in our hospital between 2015 and 2020. The efficacy endpoints were the change in SLE Disease Activity Index 2000 score, prednisolone dose, and disease status over 12 months, as well as treatment continuation rates. The safety endpoint was the frequency of adverse events over 1 year before and after switching. Cox hazard regression analyses were used to identify the predictive factors for treatment failure.

RESULTS

Thirty-nine patients (age, 41.5 ± 12.6 years; 35 women and 4 men) were analysed. The SLE Disease Activity Index score and prednisolone dose were significantly reduced after switching, with few disease exacerbations over 12 months. The 1- and 2-year continuation rates were 71.4% and 62.3%, respectively. The frequency of adverse events was similar in the year before and after switching the drug. Drug switching due to inadequate efficacy was a predictive factor of less likely treatment failure.

CONCLUSIONS

Immunosuppressive drug switching led to reduced disease activity and decreased glucocorticoid dose without disease exacerbations and severe adverse events.

Hydroxychloroquine versus tacrolimus for the treatment of persistently active systemic lupus erythematosus

OBJECTIVES

We aimed to reveal the effectiveness of hydroxychloroquine (HCQ) compared with tacrolimus (TAC), an immunosuppressive agent, in patients with systemic lupus erythematosus (SLE) with persistent activity on standard treatment.

METHODS

We retrospectively compared the efficacy and safety of the treatment between 18 patients receiving HCQ and 27 patients receiving TAC. None of the patients were in the lupus low disease activity state (LLDAS) at the beginning of this study. The efficacy end points were the cumulative incidence of LLDAS attainment without additional immunosuppressive agents, drug continuation rate, and treatment failure-free survival. The safety end point was the frequency of adverse events.

RESULTS

Eight (44.4%) patients in the HCQ group and 10 (37.0%) patients in the TAC group achieved LLDAS during the follow-up period; thus, the cumulative incidences of LLDAS attainment of the two treatments were nearly identical. The drug continuation and treatment failure-free survival rates were also not different between the two groups. The frequency of adverse events showed no clear differences between the two groups.

CONCLUSIONS

The efficacy and safety of an add-on treatment with HCQ are similar to those with TAC. Patients with persistently active SLE can benefit from HCQ in efforts to achieve at least low disease activity.

Population pharmacokinetics model and initial dose optimization of tacrolimus in children and adolescents with lupus nephritis based on real-world data

The present study aimed to establish a population pharmacokinetics model of tacrolimus and further optimize the initial dosing regimen of tacrolimus in pediatric and adolescent patients with lupus nephritis (LN). Pediatric and adolescent patients with LN were recruited between August 2014 and September 2019 at the Children's Hospital of Fudan University (Shanghai, China). Relevant information was used to set up a population pharmacokinetics model with a Nonlinear Mixed Effect Model and the initial dosage regimen was simulated with the Monte Carlo method. Body weight and co-administration of wuzhi capsule were indicated to influence tacrolimus clearance in pediatric and adolescent patients with LN, and at the same body weight, the rate of tacrolimus clearance in patients without vs. with co-administration of wuzhi capsule was 1:0.71. In addition, in patients who were not administered wuzhi capsule, an initial dosage regimen of 0.15 mg/kg/day was recommended for a body weight of 10-23 kg and 0.10 mg/kg/day for 23-60 kg; in patients who were administered wuzhi capsule, an initial dosage regimen of 0.10 mg/kg/day was recommended for a body weight of 10-23 kg and 0.05 mg/kg/day for 23-60 kg. To the best of our knowledge, the present study was the first to establish a population pharmacokinetics model of tacrolimus in order to determine the optimal initial dosage regimen of tacrolimus in pediatric and adolescent patients with LN.

Efficacy of mycophenolate mofetil in Japanese patients with systemic lupus erythematosus

OBJECTIVES

To assess the renal and non-renal efficacy of mycophenolate mofetil (MMF) in Japanese patients with systemic lupus erythematosus (SLE).

METHODS

We conducted a retrospective study to assess the renal and non-renal efficacies of MMF in Japanese patients with systemic lupus erythematosus (SLE). We analyzed 14 patients with lupus nephritis (LN) who were given MMF, and 13 patients who received monthly intravenous cyclophosphamide (IVCY) as induction therapy, and a further 19 patients without LN who were treated with MMF, and 13 patients who took tacrolimus (TAC) to reduce glucocorticoid dosages. We assessed the therapeutic effects of each therapeutic regime on renal and non-renal disease manifestations over a six-month period after treatment initiation.

RESULTS

Median urine protein to creatinine ratios in the MMF and IVCY groups significantly decreased from 2.2 to 0.7 g/gCr and from 3.3 to 0.5 g/gCr, respectively. Significant improvements in serum immunological variables (serum complements C3 and C4 and the anti-double stranded DNA antibody) and reductions in the SLE disease activity index (SLEDAI) and daily prednisolone dosages were observed in each group with LN. MMF and TAC significantly improved SLEDAI and serum immunological variables and reduced daily prednisolone dosages in patients without LN.

CONCLUSION

The present results demonstrated that MMF might be an effective treatment for renal and non-renal manifestations in Japanese patients with SLE and has potential as a good therapeutic alternative and steroid-sparing agent.

Tacrolimus in non-Asian patients with SLE: a real-life experience from three European centres

Objectives

To analyse the real-life practice on the use of Tacrolimus (TAC) in patients with systemic lupus erythematosus (SLE) from three European SLE referral centres.

Methods

Adult patients with SLE regularly followed at three European referral centres were included. Demographics, cumulative organ involvement, treatment history, Systemic Lupus Disease Activity Index (SLEDAI), laboratory features and physician's judgement were collected at baseline and at 3-6-12 months after starting TAC.

Results

29 patients were included (89% female, mean age 38±9 years). Ethnicity was predominantly Caucasian (82%), Black African (11%), Hispanic (3.5%) and Caribbean (3.5%). The main indications for TAC prescription were renal involvement (82.7%), arthritis (10.3%), cutaneous manifestations (6.8%), haematological manifestations (6.8%), serositis (3.4%). At 3 months, there was a clinical improvement in 21 patients (72.4%) and 9 of these experienced a complete resolution of symptoms (31%). This corresponds to: (1) a significant decrease in the mean SLEDAI; (2) a significant decrease in the mean 24  hours proteinuria; a significant increase in C3 and stable creatinine values. At 6 months (n=25), the physician declared an improvement in 19 patients (76%) and a complete resolution of symptoms in 9 (36%). The same trend was observed at 12 months of follow-up. TAC was discontinued in nine pts (31%); reasons for discontinuation were inefficacy (13.8%), drug intolerance (10%) and disease remission (6.9%).

Conclusions

Despite the limitation due to the small number of patients and the uncontrolled nature of the study, these data show that TAC can be considered a valid therapeutic option in patients with SLE, especially for renal involvement.

The efficacy of adjunct tacrolimus treatment in pregnancy outcomes in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) involves multiple organ systems and primarily affects women during their reproductive years. Pregnancy in a woman with SLE may lead to higher rates of disease flares. Little is known regarding which medications are safe to maintain remission and/or treat flares throughout such pregnancies. Here we retrospectively analyzed the efficacy of tacrolimus (TAC) in the pregnancy outcomes of SLE patients. We studied the 54 deliveries of 40 SLE patients over an eight-year period from 2008 to 2016. We used analyses of covariance with adjustments for the propensity score and inverse probability of treatment weights to compare the patient backgrounds between the TAC users and non-TAC users. TAC was administered to the patient in 15 of the 54 (27.8%) pregnancies, and these patients had a significantly higher dose of prednisolone, hypocomplementemia, lower estimated glomerular filtration rate, past history of lupus nephritis, and complication with antiphospholipid syndrome. In the adjusted background of the TAC deliveries, the risks of decreased fetal body weight, low birth weight infant, non-reassuring fetal status (NRFS), and preterm birth were not increased compared to the non-TAC deliveries. Thrombocytopenia and hypertension during the pregnancy were extracted as independent predictive risk factors for decreased fetal body weight and NRFS, respectively. We had anticipated that the maternal and fetal outcomes in the TAC-use deliveries would be poor before the analysis; however, the TAC-use group showed no significant difference in risks contributing to outcomes compared to the non-TAC group, suggesting that adjunct TAC treatment corrected various risk factors during the lupus pregnancies.

Calcineurin inhibitors in systemic lupus erythematosus

The calcineurin inhibitors (CNIs) belong to a group of immunosuppressive agents that block T-cell activation through the suppression of the calcium/calcimodulin-dependent phosphatase calcineurin. Agents such as cyclosporine A (CSA) and tacrolimus (TAC) have long been used in patients with systemic lupus erythematosus (SLE). TAC is preferred to CSA in SLE because of the lower frequency of cosmetic, hypertensive and dyslipidemic adverse effects. Recent randomised controlled trials have demonstrated noninferiority of TAC to mycophenolate mofetil (MMF) or cyclophosphamide (CYC) for induction therapy of lupus nephritis. Low-dose combination of TAC and MMF has also been shown to outperform CYC pulses in inducing remission of lupus nephritis in Chinese patients. TAC does not affect fertility and is relatively safe in pregnancy. In SLE patients who are intolerant or refractory to conventional immunosuppressives, or where contraindications to other immunosuppressive agents exist, TAC is an alternative option. However, the therapeutic window of TAC is narrow, and drug level monitoring is required to ensure drug exposure and minimise toxicities. Current evidence of TAC in lupus nephritis is limited to 6 months, and its long-term safety as maintenance therapy of SLE is yet to be determined. Newer chemical analogues of CNIs, such as voclosporin, with less variable plasma concentration are being tested in lupus nephritis.

Efficacy and safety of tacrolimus in systemic lupus erythematosus patients with refractory thrombocytopenia: a retrospective study

Objective

We evaluated the efficacy and safety of tacrolimus in systemic lupus erythematosus patients with refractory thrombocytopenia.

Methods

We retrospectively reviewed the data for 20 systemic lupus erythematosus patients with refractory thrombocytopenia and treated with tacrolimus during the period January 2013 to January 2015. In addition to glucocorticoids, all patients were treated with tacrolimus, 1 mg taken twice daily. The clinical effect of tacrolimus treatment in patients was evaluated by analysis of platelet counts at baseline and after one, three and six months of tacrolimus treatment. Levels of anti-double-stranded DNA antibodies and complement C3, C4 were determined individually.

Results

After one month of tacrolimus treatment, three patients (15%) did not respond, three patients (15%) achieved a complete response and the other 14 patients (75%) achieved a partial response. After three months of tacrolimus treatment, the platelet counts of all patients were significantly improved. A partial response was seen in 14 patients (75%) and the complete response rate increased to 25% (five patients). After six months, all patients attained partial response or complete response without relapse, and the rate of complete response increased to 75%. Compared to pretreatment, anti-double-stranded DNA antibody levels and the disease activity index score were markedly decreased after tacrolimus treatment. The levels of serum C3 and C4 were increased significantly ( P < 0.05).

Conclusions

Our survey revealed that a six-month course of tacrolimus is a safe and effective treatment for systemic lupus erythematosus patients with refractory thrombocytopenia.