Clinical trial NCT00001213: Cysteamine Eye Drops to Treat Corneal Crystals in Cystinosis
Official title: Trial of Topical Cysteamine in the Treatment of Corneal Cystine Crystal Accumulation in Cystinosis
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE2
Conditions: Cystinosis
Keywords: Cysteamine Eye Drops
Nephropathic Cystinosis
Corneal Crystals
Benzalkonium
Toxicity
Efficacy
Cystinosis
Lead sponsor: National Institutes of Health Clinical Center (CC)
Sponsor class: NIH
First posted: 1999-11-04
Enrollment: 328
Sex: ALL
Minimum age (years): 2
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: TREATMENT

Brief summary: Cystinosis is an inherited disease that results in poor growth and kidney disease, among other things. The damage to the kidneys and other organs is thought to be due to accumulation of cystine inside the cells of various body tissues. This chemical also accumulates in the cornea-the covering of the eye over the pupil and iris. After 10 to 20 years, the corneas of some patients become so packed with crystals that the surfaces may become irregular, occasionally causing small, painful breaks.

Patients enrolled in a NIH study on cystinosis are receiving the drug cysteamine. Taken by mouth, this drug reduces cystine in some tissues, but not in the cornea. This study began in 1986 to test whether cysteamine eye drops could prevent or reduce corneal cystine crystals in these patients. The drops have been very effective in removing crystals and reducing pain in patients who take the medication as directed. Patients who do not take the medication as prescribed do not benefit.

After the effectiveness of the drops was proven, the main purpose was modified to continue to evaluate the long-term safety and effectiveness of cysteamine eye drops for treating cystine crystals in the corneas of patients with cystinosis until the drops are approved by the Food and Drug Administration (FDA). When the New Drug Application (NDA) for the Sigma-Tau standard formulation is granted, this protocol will be terminated.

Detailed description: Protocol 86-EI-0062 began as a randomized, double-masked, placebo controlled study to evaluate the efficacy and safety of 0.5% topical cysteamine but was subsequently amended as a natural history protocol. Additional protocols conducted at the National Eye Institute (NEI) at the National Institutes of Health (NIH) began after this protocol and tested various formulations of cysteamine topical solution for efficacy and safety in patients with cystinosis. Subjects from these NIH protocols testing various formulations were ultimately transferred to this natural history protocol for open-label treatment once it was established that the formulation within this study was the most effective. All subjects enrolled in this protocol received the most effective cysteamine topical solution formulation in both eyes. The control was defined as the natural course of corneal crystal accumulation in patients with cystinosis. The efficacy data were obtained from all of the studies conducted at NIH evaluating various cysteamine ophthalmic solution formulations from 1986 until 2005. The safety data were collected from 1986 until the termination of this protocol in July 2013.

OBJECTIVE:

The free thiol cysteamine depletes cystinotic leukocytes and other cells of cystine, whose accumulation is considered the cause of organ damage in cystinosis. This organ damage involves most tissues of the body. Cysteamine therapy improved growth and stabilized renal function in pre-renal transplant cystinosis, without substantial toxicity but there was no noticeable effect on cystine crystal accumulation in the cornea, most likely because of inadequate local cysteamine concentration in the cornea. Previous studies have shown the safety of cysteamine 0.5% topical solution in benzalkonium chloride and its efficacy in resolving the cystine corneal crystals. The main purpose of this protocol is to maintain topical cysteamine treatment in patients with nephropathic cystinosis until the drops are approved by the FDA. When the NDA for the Sigma-Tau standard formulation is granted, the present protocol (86-EI-0062) will be terminated.

STUDY POPULATION:

Up to 350 adults and children over two years old, who have a confirmed diagnosis of cystinosis will be enrolled.

STUDY DESIGN:

This is an open label treatment protocol. Eligible subjects will receive drops of cysteamine 0.5% topical solution in benzalkonium chloride hourly while awake in both eyes. They will undergo an eye examination at their baseline visit. They will take cysteamine eye drops in both eyes every hour during waking hours. They will return to the NIH Clinical Center for a follow-up safety eye examination one year after the baseline visit, and then every two years thereafter until the drug is available commercially.

OUTCOME MEASURES:

The initial pre-specified primary outcome measure was the reduction of cystine corneal crystals. The post-hoc primary outcome measure (after the protocol was modified) was the collection of safety data.

Eligibility criteria: INCLUSION CRITERIA:

* Patients must have a documented clinical diagnosis of cystinosis.
* Patients should be 2 years old or older.

EXCLUSION CRITERIA:

* Inability to travel to NIH for a baseline examination, after 1 year, and every two years thereafter for follow-up
* Inability to cooperate for slit-lamp examination

Primary outcomes:
measure: Number of Participants With Serious and Non-Serious Adverse Events
timeFrame: Any Time Point up to 27 Years
measure: Number of Eyes With a Corneal Cystine Crystal Score (CCCS) Response
timeFrame: Any Time Point Up to 19 Years
Secondary outcomes:
Other outcomes:
Locations:
city: Bethesda
country: United States
facility: National Institutes of Health Clinical Center, 9000 Rockville Pike
state: Maryland
Study officials:
affiliation: National Eye Institute (NEI)
name: Rachel J Bishop, M.D.
role: PRINCIPAL_INVESTIGATOR
References:
citation: Kaiser-Kupfer MI, Fujikawa L, Kuwabara T, Jain S, Gahl WA. Removal of corneal crystals by topical cysteamine in nephropathic cystinosis. N Engl J Med. 1987 Mar 26;316(13):775-9. doi: 10.1056/NEJM198703263161304.
citation: Kaiser-Kupfer MI, Gazzo MA, Datiles MB, Caruso RC, Kuehl EM, Gahl WA. A randomized placebo-controlled trial of cysteamine eye drops in nephropathic cystinosis. Arch Ophthalmol. 1990 May;108(5):689-93. doi: 10.1001/archopht.1990.01070070075038.
citation: Gahl WA. Cystinosis coming of age. Adv Pediatr. 1986;33:95-126. No abstract available.
citation: Gahl WA, Kuehl EM, Iwata F, Lindblad A, Kaiser-Kupfer MI. Corneal crystals in nephropathic cystinosis: natural history and treatment with cysteamine eyedrops. Mol Genet Metab. 2000 Sep-Oct;71(1-2):100-20. doi: 10.1006/mgme.2000.3062.
citation: Iwata F, Kuehl EM, Reed GF, McCain LM, Gahl WA, Kaiser-Kupfer MI. A randomized clinical trial of topical cysteamine disulfide (cystamine) versus free thiol (cysteamine) in the treatment of corneal cystine crystals in cystinosis. Mol Genet Metab. 1998 Aug;64(4):237-42. doi: 10.1006/mgme.1998.2725.