Preclinical and clinical study of FK506 in uveitis

Long-Term Safety and Efficacy of Tacrolimus 0.1% in Severe Pediatric Vernal Keratoconjunctivitis

PURPOSE

The aim of this study was to evaluate the safety and efficacy of tacrolimus 0.1% eye drops in a large population of pediatric patients affected by a severe form of vernal keratoconjunctivitis (VKC) who responded poorly to cyclosporine eye drops.

METHODS

This is a retrospective study based on standardized clinical charts and data collection of consecutive patients affected by severe VKC who responded poorly to cyclosporine eye drops topical treatment but treated with tacrolimus 0.1% eye drops with a follow-up of 18 months. Four clinical signs were graded for analysis: hyperemia, tarsal papillae, giant papillae, and limbal papillae. The blood tests for kidney and liver function and the tacrolimus level were studied. Visits were scheduled at baseline and at 3, 6, 12, and 18 months. Patients received tacrolimus 0.1% eye drops in both eyes 2 times daily.

RESULTS

Four hundred thirty-one patients were included. Three hundred twenty-five patients were affected by a seasonal form, whereas the remaining 106 by a perennial form. Statistical analysis on each single score showed a positive relevance (P < 0.001) from baseline to all other visits. No local or systemic complications were recorded.

CONCLUSIONS

Tacrolimus has been proposed as a treatment for severe forms of VKC. This study has confirmed the safety and efficacy of tacrolimus 0.1% eye drops in a large pediatric population of patients affected by a severe form of VKC who responded poorly to cyclosporine eye drops.

Long-Term Follow-up of Tacrolimus Treatment in Immune Posterior Uveitis

PURPOSE

To study the efficacy of tacrolimus in immune posterior uveitis.

METHODS

Twenty-one eyes of 11 patients with immune posterior uveitis under tacrolimus treatment were prospectively followed for 1 to 5 years. Tacrolimus dosage was adjusted to maintain blood levels in the range of 7 to 10 ng/mL. Systemic and ophthalmic evaluations were performed at baseline and during follow-up.

RESULTS

After a mean follow-up of 45 months, no treatment other than tacrolimus was necessary to control the inflammation in 6 cases (54.5%). The number of annual recurrences decreased from 3.2 to 1.29 during tacrolimus treatment (p=0.021). In four patients, tacrolimus was suspended after a treatment period of 27+/-3.5 months and a follow-up period of 12 months free of uveitis relapses. All four were free from relapses following tacrolimus withdrawal. Visual acuity remained unchanged in 16/21 (76%) eyes, deteriorated in 4/21 (19%), and improved in 1/21 (5%). Renal function transiently deteriorated in four patients from basal serum creatinine levels of 0.84, 1.1, 0.88, and 0.78 mg/dL to maximum levels of 1.33, 2.48, 1.38, and 1.39 mg/dL, respectively. This deterioration was directly related with elevated tacrolimus serum levels, returning to normal when doses were reduced. During the overall controlled evolution period, a slight increase of serum creatinine from a basal value of 0.89+/-0.2 mg/dL to a final of 1+/-0.19 mg/dL was detected, which was not statistically significant. All secondary effects were mild, transient, and did not require interruption of long-term treatment to be controlled.

CONCLUSIONS

Tacrolimus was well tolerated and useful in controlling posterior immune uveitis. Tacrolimus could be considered a real alternative to cyclosporine, and not only in cases of cyclosporine resistance or toxicity.

Safety profile and efficacy of tacrolimus in the treatment of birdshot retinochoroiditis: a retrospective case series review

AIM

Evaluation of the use of tacrolimus in the treatment of birdshot retinochoroiditis (BRC) at a tertiary referral centre with the aim to describe its safety and efficacy.

METHODS

The medical records of 25 patients diagnosed with BRC at uveitis service, Moorfields Eye Hospital, and who had received tacrolimus treatment were retrospectively reviewed. The main outcome measures of the study were (1) safety of tacrolimus in terms of side effects and (2) efficacy, as measured both by control of inflammation and visual function assessed by Humphrey visual fields and electrophysiological testing over at least 6 months and then 1 year.

RESULTS

Tacrolimus was commenced in 25 patients (mean age 50.4±10.8 years) and was well tolerated in 21 patients (84%). It was necessary to stop the tacrolimus in four patients. No patient showed major changes in renal function: 3/21 patients (14.28%) showed slightly abnormal (less than 30%) function at the end of the first month of treatment; 1/21 (4.76%) patients at 3 months, but at the end of a 6-month treatment period only 1/21 patients (4.76%) showed minor abnormality in renal function. The mean daily prednisolone dose was 19.7 mg at the beginning of the study, which had fallen to 6.9 mg at the end (t=5.071, p=0.001). Visual acuity mostly remained stable. Visual fields improved over time (mean improvement in Humphrey mean deviation, right eye=1.8±2.4 dB, t=3.821, p=0.004; left eye=1.9±2.7, dB, t=3.06, p=0.007). Electrophysiological function showed improvement in 10 patients, and in four patients an initial deterioration in function improved following tacrolimus dose adjustment.

CONCLUSION

Tacrolimus has a good safety profile for long-term use in patients with BRC as a second-line agent enabling steroid sparing and visual function stabilisation or improvement.

Systemic Immunomodulatory Strategies in High-risk Corneal Transplantation

The cornea is the most commonly transplanted tissue in the body. Although corneal grafts generally have high success rates, transplantation onto inflamed and vascularized host beds, or so-called high-risk corneal transplantation, has a high rate of graft rejection. The management of this high-risk corneal transplantation is challenging and involves numerous measures. One of the key measures to prevent graft rejection in these cases is the use of systemic immunosuppressive agents. In this article, we will review the systemic immunosuppressive agents most commonly used for high-risk corneal transplantation, which include corticosteroids, cysclosporine A, tacrolimus, mycophenolate mofetil, and rapamycin. Benefits, risks, and published data on the use of these medications for high-risk corneal transplantation will be detailed. We will also summarize novel immunoregulatory approaches that may be used to prevent graft rejection in high-risk corneal transplantation.

Efficacy and safety of systemic tacrolimus in high-risk penetrating keratoplasty after graft failure with systemic cyclosporine

PURPOSE

The aim of this study was to investigate the efficacy and safety of systemic tacrolimus for the treatment of eyes that developed graft failure despite treatment with cyclosporine (CsA).

METHODS

Ten eyes of 10 patients who underwent high-risk penetrating keratoplasty (PKP) and developed graft failure despite treatment with systemic CsA were included in this study. The patients underwent PKP and were treated with systemic tacrolimus according to the standardized protocol.

RESULTS

Treatment with tacrolimus was continued for 18.1 ± 13.9 months. The median duration of corneal graft clarity was 34.5 months. Graft rejection occurred in 2 of 10 eyes during a mean follow-up period of 48.9 ± 22.9 months. Kaplan-Meier survival plots showed significantly fewer graft rejection episodes (P = 0.033) and longer graft survival (P = 0.042) after treatment with tacrolimus compared those with CsA. Tacrolimus was discontinued in 2 patients; 1 had renal dysfunction and the other had muscle pain and fatigue. These side effects subsided after discontinuation of tacrolimus.

CONCLUSIONS

Treatment with systemic tacrolimus is possibly safe and effective in reducing graft rejection and prolonging graft survival in patients with high-risk PKP after graft failure with systemic CsA.

Update on the therapy of Behçet disease

Behçet disease is a chronic inflammatory systemic disorder, characterized by a relapsing and remitting course. It manifests with oral and genital ulcerations, skin lesions, uveitis, and vascular, central nervous system and gastrointestinal involvement. The main histopathological finding is a widespread vasculitis of the arteries and veins of any size. The cause of this disease is presumed to be multifactorial involving infectious triggers, genetic predisposition, and dysregulation of the immune system. As the clinical expression of Behçet disease is heterogeneous, pharmacological therapy is variable and depends largely on the severity of the disease and organ involvement. Treatment of Behçet disease continues to be based largely on anecdotal case reports, case series, and a few randomized clinical trials.

Topical 0.005% tacrolimus eye drop for refractory vernal keratoconjunctivitis

PURPOSE

To evaluate the efficacy and safety of topical 0.005% tacrolimus eye drop for treatment of refractory vernal keratoconjunctivitis (VKC).

METHODS

This prospective study included 20 eyes of 10 patients with refractory VKC, who had active symptomatic disease despite conventional medications including topical steroids. After discontinuing all other medications, patients were treated with topical 0.005% tacrolimus eye drop four times a day. Changes in subjective symptoms and objective signs after treatment were evaluated, and development of possible complications was assessed.

RESULTS

Mean age of patients was 21.3±7.4 years and mean duration of VKC was 12.1±5.8 years. After starting tacrolimus eye drop, patients were followed for a mean duration of 10.7±3.7 months (range, 6-15 months). All symptoms including itching, redness, photosensitivity, foreign body sensation, and mucus discharge improved after the treatment; itching was the first symptom to show dramatic relief. In addition, there was improvement in objective signs including conjunctival hyperaemia, conjunctival papillary hypertrophy, giant papillae, limbal hypertrophy, corneal punctate epithelial erosions, and corneal pannus; conjunctival hyperaemia was the first sign to show improvement. No patient required addition of other medications including steroids for further relief. Any attempt to discontinue tacrolimus eye drop was associated with recurrence of patients' symptoms and signs, necessitating continued use of the medication during the entire follow-up time. No ocular complication related to tacrolimus was noted.

CONCLUSION

Topical 0.005% tacrolimus eye drop seemed to be a safe and effective treatment for steroid-resistant refractory VKC; however, long-term use was needed to control the disease.

Intraoperative intravitreal injection of triamcinolone acetonide for cataract extraction in patients with uveitis

PURPOSE

To evaluate the efficacy of intravitreal triamcinolone injection in controlling postoperative inflammation after cataract extraction in patients with uveitis.

METHODS

This retrospective study included 30 eyes with uveitis that had phacoemulsification or extracapsular cataract extraction with intraocular lens implantation. Intravitreal triamcinolone acetonide (4 mg) was injected at the end of surgery. No systemic steroids were given after surgery.

RESULTS

Visual acuity improvement of 2 lines or more occurred in 26 eyes (86.7%). Six eyes (20%) had a best-corrected visual acuity of 6/60 or better before surgery, which increased to 22 eyes (73.3%) after surgery. Five eyes (16.7%) had a visual acuity of 6/12 or better after surgery. Intravitreal triamcinolone injection controlled the postoperative inflammation in all eyes for at least 3 months following surgery.

CONCLUSION

Intravitreal triamcinolone injection was effective in controlling postoperative inflammation after cataract extraction in patients with uveitis sparing the use of systemic steroids.

Immunomodulatory therapy for ocular inflammatory disease: a basic manual and review of the literature

Corticosteroids are used as first-line treatment for many ocular inflammatory conditions. The risk of adverse effects, however, necessitates conversion to steroid-sparing immunomodulatory therapy (IMT) for disease that is recurrent, chronic, or poorly responsive to treatment. Combination drug treatments with multiple agent 'recipes' are also considered. Immunomodulatory agents include the broad categories of antimetabolites (azathioprine, methotrexate, mycophenolate mofetil), alkylating agents (cyclophosphamide, chlorambucil), T-cell inhibitors (cyclosporine, tacrolimus), and cytokines (interferon alfa). This article reviews and summarizes the evidence for IMT agent use in the treatment of various forms of ocular inflammation.

Effects of intravitreal injection of tacrolimus (FK506) in experimental uveitis

PURPOSE

To examine the immunosuppressive and neuroprotective effects of intravitreal injection of tacrolimus in experimental uveitis.

METHODS

Tacrolimus (40 microg) was injected intravitreally in rabbits to examine safety. Experimental uveitis was induced in rabbits by systemic immunization with bovine serum albumin (BSA) followed by intravitreal challenge with BSA. On day 1 after BSA challenge, tacrolimus (20 or 40 microg) or betamethasone (400 microg) was injected intravitreally in one eye and balanced salt solution in the contralateral eye. The eyes were evaluated by slit-lamp biomicroscopy, electroretinography, and histopathology.

RESULTS

No local or systemic adverse reaction was observed in normal rabbits. In experimental uveitis, intravitreal injection of tacrolimus significantly reduced intraocular inflammation in histopathological analysis (p < 0.03). Amplitudes on the electroretinogram were restored (p < 0.01), and retinal thickness was preserved in tacrolimus-treated eyes (p < 0.03).

CONCLUSIONS

In experimental uveitis, intravitreal injection of tacrolimus effectively suppresses ocular inflammation and preserves retinal architecture.

Clinical outcome of chronic immunosuppression in patients with non-infectious uveitis

AIM

To determine the visual outcome and corticosteroid dose requirement in patients with non-infectious uveitis affecting the posterior segment treated with corticosteroids and additional second-line immunosuppression.

METHOD

A retrospective, non-comparative case series was carried out. Seventy-two patients (141 eyes) with uncontrolled non-infectious uveitis on systemic prednisolone were treated with at least one second-line immunosuppressive agent in addition to systemic prednisolone and followed for at least 3 months. Visual acuity (VA), clinical disease activity, corticosteroid-sparing effect, disease relapses requiring corticosteroid dose increase,and side-effects from second-line agents were evaluated.

RESULTS

At the end of the follow-up period (mean: 55.5 months),70 eyes (49.6%) had VA of 6/9 or better. There was a reduction in the mean maintenance dose of prednisolone required before the introduction of the second-line agent (19 mg/day +/- 2 SE)when compared to the mean maintenance dose of prednisolone at the end of the data collection (9 mg/day +/- 1 SE; P <0.001). There was also a significant reduction in the number of disease relapses requiring an increase in prednisolone dose after starting the second-line agents as compared to the year before (P <0.02).

CONCLUSION

In patients with uveitis affecting the posterior segment, the addition of all second-line immunosuppressive therapy was effective in allowing reduction of the dose of systemic prednisolone to 10 mg/day or less, in controlling intraocular inflammation, reducing the number of relapses and in maintaining vision. Because of their side-effects, immunosuppressive treatment should be individualized and monitored closely but its addition is beneficial in the short and longer term.

Effects of tacrolimus on ischemia-reperfusion injury

In addition to efficacious immunosuppression for the benefit of organ transplantation, tacrolimus has diverse actions that result in amelioration of ischemia-reperfusion injury. Knowledge is accumulating rapidly on the mechanisms through which tacrolimus exerts these cytoprotective effects, including alterations in microcirculation, free radical metabolism, calcium-activated pathways, inflammatory cascades, mitochondrial stability, apoptosis, stress-response proteins, and tissue recovery. Within the nucleus, actions mediating the effects of tacrolimus appear to be dominantly influenced by interactions with the transcription factor, nuclear factor-kappaB. Because tacrolimus is a cornerstone agent in immunosuppression regimens throughout the world and knowledge of its cellular mechanisms is evolving, it is important to update the clinical literature with this information. We reviewed the published literature with intent to portray the interactions of tacrolimus in the intricate cellular mechanisms initiated by ischemia and reperfusion.

Review: uveitis and immunosuppressive drugs

Uveitis, inflammation of the eye, is a common occurring disease resulting from a wide variety of traumatic and immunogenic insults and, in most cases, can be treated successfully by corticosteroids. However, corticosteroids have severe side effects. Alternative therapy is using nonsteroidal anti-inflammatory agents like indomethecin, diclofenac and flurbiprofen. The uveitic cases are prominent in the third world countries, and many of the patients are not responsive or become refractory to steroidal or nonsteroidal therapy. Therefore, there is another class of compounds "immunosuppressive drugs" found to be successful in treating uveitis. These include cyclosporin A, tacrolimus, and sirolimus. However, being immunosuppressive they also have side effects. Therefore, the effective therapy with lower side effects is the treatment with combination of these drugs in lower dosages. Cyclosporin A plus sirolimus or tacrolimus in threshold doses alleviate signs of uveitis with lower incidence of side effects.

Tacrolimus (FK506) in failed cyclosporin A therapy in endogenous posterior uveitis

Tacrolimus (FK506) is effective in Japanese endogenous posterior uveitis (EPU), but there is limited data on its role in refractory EPU where cyclosporin A (CsA) toxicity/resistance develops. This open prospective clinical study aimed to assess the efficacy and adverse effects of low-dose FK506 therapy in western patients with refractory EPU where CsA resistance or toxicity has developed. Patients with CsA resistant/toxic EPU were started on low-dose (< 0.10 mg/kg/day) FK506 therapy. Immunosuppressive efficacy was assessed by visual acuity, binocular indirect ophthalmoscopy (BIO) scores, and change in clinical features. Adverse effects were assessed by routine biochemical tests (including serum creatinine) and symptoms. Seven patients (13 eyes), aged (mean +/- SD) 37.5 +/- 14.8 years, were recruited with previous CsA nephrotoxicity as the main indication and prior duration of EPU of (mean +/- SD) 13.1 +/- 7.3 years. Behçet's disease was the commonest diagnosis. FK506 therapy was maintained at 0.06 +/- 0.02 mg/kg/day, trough level of 8.7 +/- 1.8 ng/ml, in combination with low-dose prednisolone (0.11 +/- 0.04 mg/kg/day) in all patients for a mean duration of 8.7 months (range 1.0-17.7). From baseline (for 11 eyes with meaningful follow-up), visual acuity was maintained in nine eyes and BIO score improved in nine eyes. No major adverse effects developed, with only a 7.5 +/- 6.5% maximum increase in serum creatinine in patients with previous CsA-induced nephrotoxicity. Minor adverse effects (especially mild hyperglycaemia and neurological symptoms) were common and usually well tolerated, except for two patients in whom drug withdrawal was necessary, thus producing therapeutic failure. Low-dose FK506 is effective in refractory EPU as CsA-rescue therapy, and should be considered earlier in the evolution of refractory EPU.

FK506 treatment of noninfectious uveitis

PURPOSE

We studied the clinical effects of the immunosuppressive agent FK506 in patients with noninfectious uveitis.

METHODS

This study was designed as a multicenter open clinical trial in Japan. Sixteen patients with noninfectious uveitis who had visited the Uveitis Survey Clinic of the Yokohama City University Hospital were given FK506. Eight had Behçet's disease; five, Vogt-Koyanagi-Harada syndrome; one, sympathetic ophthalmia; one, retinal vasculitis; and one, sarcoidosis. In patients with Behçet's disease, ocular attack score before and after therapy was compared to judge clinical status. For the other diseases, the ocular inflammatory symptoms were observed after the initiation of FK506 treatment. All patients underwent blood and urine examinations, electrocardiography, and chest x-rays before and after FK506 treatment.

RESULTS

Of the patients with Behçet's disease, five improved, one remained unchanged, one deteriorated, and the status of one could not be determined. Of the patients with Vogt-Koyanagi-Harada syndrome, four improved, and one remained unchanged. The patient with sympathetic ophthalmia improved, the patient with retinal vasculitis remained unchanged, and the status of the patient with sarcoidosis could not be determined. Major adverse effects were sensations of warmth, hypomagnesemia, renal dysfunction, glucose intolerance, nausea, vomiting, and disorders of the central nervous system. All adverse effects disappeared or improved when FK506 was stopped or when the dosage was decreased. Renal dysfunction and glucose intolerance appeared when the blood level of FK506 was high.

CONCLUSIONS

FK506 was effective in patients with uveitis, but it is important to monitor the occurrence of adverse effects.

Immunomodulation of experimental autoimmune uveoretinitis: a model of tolerance induction with retinal antigens

Experimental autoimmune uveoretinitis (EAU) is a CD4+ T-lymphocyte mediated inflammation of the uveal tract and retina. As a model of human posterior uveitis it permits further understanding of the underlying immunopathogenesis of uveitis. It also allows for preclinical trials of immunosuppressive therapies and in vivo assessment of alternative strategies for immunointervention. This review highlights possible immunostrategic modalities which prevent the initiation or perpetuation of the immune response, and in particular reports on the novel effect of intranasal induction of tolerance with retinal antigens, prior to immunisation with retinal antigens. The mechanisms and potential application of this 'natural' method of immunosuppression in the treatment of autoimmune disease are discussed.

Splenectomy abrogates the induction of oral tolerance in experimental autoimmune uveoretinitis

Oral administration of uveitogenic antigens inhibits the development of experimental autoimmune uveoretinitis (EAU) and the cellular immune response initiated by these antigens. The mechanism of oral tolerance is not completely clear, but accumulating data indicate that suppressor cells are actively involved in this process. The spleen is known to harbor suppressor cells and their precursors and the present study was aimed at testing the role of this organ in the induction of oral tolerance by S-antigen (S-AG). We report here that: (a) splenectomy abrogated the induction of oral tolerance; unlike in sham operated controls, feeding with S-Ag did not inhibit the development of EAU in splenectomized rats; (b) splenectomized rats responded with higher cellular immune responses than did sham operated controls, but feeding with S-Ag inhibited these responses in both groups of animals; (c) splenectomy also abrogated the adoptive transfer of tolerance: EAU induction was inhibited in sham operated recipients of splenocytes from S-Ag fed donors but not in the splenectomized recipients. The data thus indicate that the spleen plays an important role in the induction of oral tolerance, perhaps by acting as the site for induction and/or amplification of cells with suppressor activity.