Experience with starting tacrolimus postoperatively after transsternal extended thymectomy in patients with myasthenia gravis

Long-Term Safety and Efficacy of Tacrolimus in Myasthenia Gravis

PURPOSE

Myasthenia gravis (MG) is a lifelong autoimmune disorder that affects neuromuscular transmission. The long-term treatment plan should include immunotherapy. We investigated the long-term safety and efficacy of tacrolimus for the treatment of MG in real-world clinical practice.

MATERIALS AND METHODS

We retrospectively reviewed 160 MG patients treated with tacrolimus from 2005 to 2015. Myasthenia Gravis Foundation of America (MGFA) clinical classification, MGFA post-intervention status, myasthenic functional score, and dose of oral prednisolone were investigated.

RESULTS

Adverse events occurred in 68 patients (42.5%), most of which were minor and well-managed. Clinical severity scales improved after administration of tacrolimus, compared to the baseline. Compared to 6 months before administration of tacrolimus, prednisolone dose significantly decreased at 12 months after treatment (2.85±0.92 mg/day, p=0.002), 18 months after treatment (3.36±0.99 mg/day, p=0.001), and 24 months after treatment (3.71±0.93 mg/day, p<0.001).

CONCLUSION

Tacrolimus may be effective in reducing the severity of MG and may permit a reduction in the steroid dose prescribed to the patients. Adverse events due to tacrolimus treatment were not serious.

Tacrolimus Improves Symptoms of Children With Myasthenia Gravis Refractory to Prednisone

BACKGROUND

Myasthenia gravis tends to affect children in China. Oral pyridostigmine and prednisone could effectively improve the symptoms, but multiple side effects become a major concern after long-term oral prednisone. To avoid the long-term complications of prednisone therapy and to obtain more satisfactory improvement, we tested the efficacy and safety of tacrolimus in children with myasthenia gravis.

METHODS

Children with myasthenia gravis who had not achieved satisfactory improvement or who experienced severe side effects after prednisone therapy were recruited between January 2015 and December 2016 at Tongji Hospital. All the children were treated with tacrolimus 1 mg to 2 mg daily and the dose was adjusted on the basis of the clinical response and the serum concentration. The dosage of prednisone, the severity of symptoms, blood samples, the serum concentration of tacrolimus, and titers of antiacetylcholine receptor antibodies were evaluated every four weeks.

RESULTS

Fourteen children were enrolled. One child withdrew two weeks after the enrollment. Thirteen children have completed the therapy for one year. At the end point, the dosage of prednisone was significantly decreased (P < 0.05), the symptoms were evaluated by the quantitative myasthenia gravis score, and myasthenia gravis-specific manual muscle testing and myasthenia gravis-activities of daily living scores were significantly improved (P < 0.05, P < 0.05, and P < 0.01, respectively). More importantly, ten (76.9%) patients had completely discontinued prednisone, and the major side effects were nearly reversed. The mean titer of antiacetylcholine receptor antibodies significantly dropped from 1.96±2.62 nmol/L to 0.70±1.04 nmol/L (P < 0.05). No severe adverse events were reported.

CONCLUSIONS

Our results suggest that tacrolimus is a promising agent for children with refractory myasthenia gravis. Randomized clinical trials are needed to confirm the observation.

Outcomes of Preoperative and Postoperative Corticosteroid Therapies in Myasthenia Gravis

AIMS

To compare the long-term outcomes of non-thymomatous myasthenia gravis (MG) patients receiving pre-thymectomy (Pre-CS) or post-thymectomy corticosteroid (Post-CS) therapy.

METHODS

In a retrospective cohort study, 41 patients with MG were treated with Pre-CS therapy, and 110 were treated with Post-CS therapy.

RESULTS

In the MG cohorts, 9 of 40 patients (22.5%) in the Pre-CS group vs. 28 of 105 patients (26.7%) in the Post-CS group achieved a complete remission (CR) at 1 year, 29.7% (11/37) vs. 38.6% (32/83) at 2 years and 36.4% (8/22) in the Pre-CS group vs. 50.0% (28/56) in the Post-CS group achieved a CR at 5 years. For the entire population, Post-CS therapy (hazard rate [HR] 3.042, p = 0.020) was a positive predictor for remission, and a long preoperative interval (HR 0.936, p = 0.030) was a negative predictor. In 98 original ocular MG patients, Post-CS therapy (HR 2.663, p = 0.014) and an age at onset ≥15 years (HR 4.865, p = 0.001) were positive predictors for remission.

DISCUSSION

Post-CS therapy with a shorter preoperative interval increases the likelihood of CR in postpubertal and adult patients.

Efficacy and Safety of Tacrolimus in Myasthenia Gravis: A Systematic Review and Meta-analysis

Aims:

This study was designed to determine whether treatments with tacrolimus would provide benefit for patients with myasthenia gravis (MG).

Materials and Methods:

The databases of Medline, EMBASE, the Cochrane Library, and four Chinese databases were searched for eligible studies. Weighted mean differences and standardized mean differences (SMD) with corresponding 95% confidence intervals (CIs) were used to summarize the primary outcome, namely, steroid-sparing effect of tacrolimus in maintaining minimal manifestations, and the secondary outcome, namely, the effect of tacrolimus in reducing the severity of MG, respectively.

Results:

After systematic retrieval, 13 researches with two randomized controlled trials (RCTs) and 11 prospective open-label single-arm clinical trials were included in the study. For the primary outcome of two RCTs, one RCT which was followed up for 1 year showed a positive effect and the other RCT which was associated with treatment duration of 28 weeks showed a negative result. For the secondary outcome, meta-analyses of other 11 trials showed a benefit effect, overall. For the quantitative MG (QMG) score, there were significant differences with high heterogeneity (SMD: 2.93; 95% CI: 1.14–4.73; I² = 86%). In contrast, for MG activities of daily living (MGADL) score, it was reduced by tacrolimus with significant SMD and less heterogeneity (SMD: 0.59; 95% CI: 0.33–0.85; I² = 7%). Adverse effects were mentioned as mild.

Discussion:

The opposite results of two RCTs showed that tacrolimus with enough treatment duration might have positive steroid-sparing effect. The most possible cause of heterogeneity in the outcome of QMG score between trials was the baseline severity of MG.

Conclusion:

The above finding suggests that there might be a potential beneficial role with no serious side effects of tacrolimus, and additional better RCTs including larger sample sizes and long-term study are needed to confirm or refute the results.

The emerging role of tacrolimus in myasthenia gravis

OBJECTIVE

To describe and evaluate the available evidence assessing the role of tacrolimus in the management of patients with myasthenia gravis (MG).

DATA SOURCES

A literature search of MEDLINE (1946 to September 2014) and EMBASE (1947 to September 2014) was performed using the terms 'tacrolimus' and 'myasthenia gravis'. Citations of retrieved articles were examined for relevance.

STUDY SELECTION AND DATA EXTRACTION

The search was limited to prospective clinical trials focused on clinical outcomes in patients with generalized MG. Case reports, retrospective evaluations and non-English articles were excluded.

DATA SYNTHESIS

A total of 12 studies met inclusion criteria, of which seven articles evaluated tacrolimus in steroid-dependent patients and two examined the utility of tacrolimus in patients failing corticosteroids and cyclosporine. Other studies evaluated early initiation of tacrolimus after thymectomy, effectiveness of tacrolimus in de novo MG and the effectiveness of tacrolimus post-thymectomy in thymoma patients versus nonthymoma. A total of eight trials showed statistically significant improvements in quantitative MG score (QMGS) and postintervention status criteria - Myasthenia Gravis Foundation of America (PSC-MGFA). Of the trials examining steroid reduction with tacrolimus, two reported high rates of complete withdrawal; however, the most robust trial was unable to detect a difference in mean steroid dose. Long-term effects of tacrolimus (up to 5 years) were assessed in eight trials, which consistently showed positive effects on QMGS or reduction in adjunct therapies.

CONCLUSIONS

There is limited yet promising information to suggest a beneficial role for tacrolimus in reducing QMGS and corticosteroid burden in patients with refractory symptoms or new-onset MG. Long-term use appears to be safe in this population.