The Vision Center at Childrens Hospital Los Angeles has been awarded a US$ 1 million grant from the National Cancer Institute (NCI) to conduct a clinical trial on a new drug delivery system to treat young children diagnosed with retinoblastoma. The device is designed to deliver chemotherapy through a tiny silicone cup sealed to the outer surface (sclera) of the eye, which can more directly target cancer cells and greatly reduce the side effects caused by current chemotherapy treatments.
The grant, given to Childrens Hospital Los Angeles, is part of an RC3 ARRA grant of US$ 2.7 million awarded to 3T Ophthalmics, Inc. by the National Cancer Institute (NCI). The phase-I clinical trial will start enrolling patients in July 2011 under the direction of A. Linn Murphree, director of the Retinoblastoma Program in The Vision Center. Dr Murphree is also professor of ophthalmology and paediatrics at the Keck School of Medicine of the University of Southern California and attending physician at both the Doheny Eye Institute and the Norris Comprehensive Cancer Center at USC.
The new delivery system, called the episcleral drug reservoir or eye port, is a small silicone cup about 8mm to 10mm in size and can hold the chemotherapy for slow sustained drug delivery to the eye. The eye port isolates the medication targeted to the eye from being absorbed into the blood stream. This new delivery system is a simple way to deliver medications to the interior of the eye over weeks to months.
Currently eye doctors use drops, injections around the eye and even injections directly into the eye to place medications where they are most needed. All of these methods, however, deliver the drug for only a few hours. Several other “slow delivery” systems are being tested but they all require major eye surgery and the risks of complications are high.
The eye port, in contrast, is firmly attached to the outside of the eye under the thin, filmy conjunctiva, or covering of the eyeball. The eye port slowly releases the drug to pass through the wall of the eye, where it reaches the retina and vitreous. The device is so small the patient should feel little or no discomfort, and it does not hinder normal vision.
“The new device could fundamentally change the delivery of medications to the eye for diseases such as macular degeneration, diabetic retinopathy, uveitis, endophthalmitis, retinopathy of prematurity and retinoblastoma. Children receiving chemotherapy could potentially return home wearing the device and avoid most of the complications of standard chemotherapy,” says Dr Murphree.
The Vision Center at Childrens Hospital Los Angeles will partner with three other US retinoblastoma centers to conduct the clinical trials; The Retinoblastoma Center of Houston (a joint programme of MD Anderson Cancer Center/University of Texas and Texas Children’s Hospital/Baylor College of Medicine); Memphis’ St. Jude’s Children’s Research Hospital; and Philadelphia’s Scheie Eye Institute.
"While we are beginning this protocol with the eye, this type of device could potentially be implanted on a variety of internal organs and could fundamentally change the way we treat many types of cancer,” said Dr Murphree.
“Currently, when we use I.V. chemotherapy to treat retinoblastoma in young children, we give high doses to ensure the medicine gets into the eye. Most of it, however, affects other parts of the body, causing nausea, a reduction in white cell count and depression of the immune system. With the eye port, we will be giving much less chemotherapy, but far more will reach the cancer cells,” said Dr Murphree. “It also offers the promise of inexpensive treatment for thousands of children in developing countries who now die of this childhood eye cancer, because their families cannot afford traditional chemotherapy,” he added.
The three-year grant will enrol 36 patients in the phase-I (Year I) trial and an additional 24 patients in phase-II. Only patients with unilateral advanced intraocular retinoblastoma that have received no previous treatment will be eligible for clinical trial enrolment.
Childrens Hospital Los Angeles is one of the nation’s leading children’s hospitals and is acknowledged worldwide for its leadership in paediatric and adolescent health.