New Study Confirms Two Treatments for AMD Provide Equal Improvements in Vision
DENVER (April 30, 2012) Two drugs commonly used to treat age-related macular degeneration (AMD) yield similar improvements in vision for patients receiving treatments on a monthly or as-needed basis, according to a study at the Perelman School of Medicine at the Center for Preventive Ophthalmology and Biostatistics (CPOB) at the University of Pennsylvania. The study was funded by the National Eye Institute and was conducted in part at Porter Adventist Hospital in Denver.
The year-two results of the Comparison of AMD Treatment Trials (CATT) support the findings from the first year of the study that evaluated the effects of Avastin (bevacizumab) - the off-label drug most frequently used to treat AMD - and Lucentis (ranibizumab), a drug approved by the FDA in 2006 for the treatment of AMD. Full long-term results of the CATT, a two-year clinical trial, are published in the current issue of Ophthalmology.
Many doctors have already been using both drugs to treat this eye disease, said Dr. Jack Zilis, lead investigator for the study at Porter, and a retinal specialist at Colorado Retina Associates in Denver. Knowing that both drugs are equal in terms of results means that treatment can be tailored to the patients response, and may allow some patients to be treated less frequently.
Improvement in visual clarity served as the primary outcome measure for the year-two results. AMD is the leading cause of vision loss and blindness in older Americans. In its advanced stages, the wet form of AMD spurs the growth of abnormal blood vessels, which leak fluid and blood into the macula - the central portion of the retina that allows us to look straight ahead and to perceive fine visual detail - and obscure vision. Accumulation of fluid and blood damages the macula causing loss of central vision. Without treatment, most patients with AMD are unable to drive, read, recognize faces or perform tasks that require hand-eye coordination.
Avastin - a drug approved for the treatment of some cancers but not AMD - and Lucentis block growth of abnormal blood vessels and leakage of fluid from the vessels. CATT was originally designed to compare the effectiveness of Avastin and Lucentis as a treatment for AMD. However, in the initial studies for AMD, Lucentis was administered monthly. For the year-two study, researchers focused on determining whether "as-needed" dosing would produce the same long-term visual improvements.
At enrollment, patients were assigned to one of four treatment groups defined by drug (Avastin or Lucentis) and dosing regimen (monthly or as-needed). Patients in the monthly dosing groups received a treatment injection every 28 days. Patients in the as-needed groups received a treatment at baseline and were then examined every 28 days to determine medical need for additional treatment. The original CATT study followed 1185 patients treated at 43 clinical centers in the United States. During year two, researchers examined the continued effects seen in 1,107 patients.
At two years, both drugs proved highly effective regardless of the dosing regimen. Clarity of vision in the patients who received monthly treatments was only slightly better than in those who received treatment as-needed, but all four groups exhibited significant improvement. After two years, two-thirds of patients had driving vision (20/40 vision or better). In previous studies, only 15 percent of patients retained similar visual acuity.
Changes in retinal anatomy differed by drug and frequency of treatment, but did not have an impact on vision through two years. Though results showed slightly less vision gain with as-needed treatment, researchers say benefits and drawbacks to both regimens should be considered by patients and clinicians.
"Patients who want the small extra advantage afforded with the monthly treatment should also be aware of the additional risks and costs of the monthly injections," said Maureen Maguire, PhD, principal investigator, CATT Coordinating Center at the University of Pennsylvania. "Those in the as-needed group ultimately required 10 fewer injections over the course of two years and experienced similar visual improvements."
Adverse events indicate development or worsening of a medical condition. They may or may not be causally associated with the clinical trial treatment, but they are always monitored and reported in any clinical trial. The median age of patients in CATT was more than 80 years, and a high rate of hospitalizations would be anticipated as a result of chronic or acute medical conditions more common to older populations.
Serious adverse events (SAEs) occurred at a 40 percent rate for patients receiving Avastin and a 32 percent rate for patients receiving Lucentis. Although Avastin had a higher rate of SAEs, they were distributed across many different conditions, most of which were not associated with Avastin when evaluated in cancer clinical trials where the drug was administered at 500 times the dose used for AMD. The number of deaths, heart attacks, and strokes were low and similar for both drugs during the study. Additional data from other clinical trials comparing Avastin and Lucentis may provide further information on the long-term safety profiles of these drugs when used to treat AMD.
About Porter Adventist Hospital
Porter Adventist Hospital is a full service, Nursing Magnet designated, 368-bed acute-care referral center for complex medicine and surgery patients. In addition to being ranked No. 1 for 2010 in overall cardiac care in Colorado by a national hospital reporting company, Porter specializes in cancer care, joint replacement, spinal care, advanced robotic surgery and organ transplantation. Porter is sponsored by Adventist Health System and is connected to Centura Health, Colorados health care leader, and its integrated statewide network of 13 hospitals, seven senior living communities, medical clinics, affiliated partner hospitals, Flight For Life Colorado, and home care and hospice services. Together, Porter and Centura Health provide care that transcends the walls of a hospital. Connections that only Centura Health can make. For more information about Porter Adventist Hospital, visit www.porterhospital.org or the Media Room at http://porter.mediaroom.com.
About the National Institutes of Health (NIH)
NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.
The National Eye Institute, part of the National Institutes of Health, leads the federal government's research on the visual system and eye diseases. NEI supports basic and clinical science programs that result in the development of sight-saving treatments. For more information, visit www.nei.nih.gov.