Retina specialists maintain prescribing habits despite CATT study results

More long-term data will provide further justification for altering treatment strategies for patients with wet AMD, clinicians say.

The 1-year results of the Comparison of Age-Related Macular Degeneration Treatment Trials, released in April, found two anti-VEGF agents to be equally effective in treating neovascular age-related macular degeneration.

Maynard L. Pohl

These findings lend support to the increased use of Avastin (bevacizumab, Genentech), which currently is used off-label and costs significantly less than Lucentis (ranibizumab, Genentech). However a recent survey conducted by the American Society of Retina Specialists has found that 73.24% of specialists have not changed their prescribing habits in light of these findings.

PCON talked with two clinicians about the CATT study 1-year findings, their clinical implications and why some retinal specialists are using caution in changing their prescribing habits.

“The survey is not surprising,” Maynard L. Pohl, OD, FAAO, of Pacific Cataract and Laser Institute in Bellevue, Wash., told Primary Care Optometry News. “It suggests that retinal specialists, for the most part, are holding the course on prescribing habits until further substantiation for switching is provided.”

Comparable visual benefits

The 1-year results of the study found that Avastin and Lucentis yielded comparable visual acuity benefits, with 25% to 34% of eyes in the study improving substantially. Patients dosed monthly with Avastin gained 8.0 letters of vision, vs. monthly Lucentis recipients, who gained 8.5 letters. More than 90% of affected eyes did not progress in terms of vision loss.

“The great thing about this study is that it shows that both medications are safe and effective,” Jessica McCluskey, MD, a retinal specialist practicing in Atlanta, said in an interview. “There has been some concern among patients about the off-label usage of Avastin. I think these findings can be useful in addressing those concerns.”

Both Avastin and Lucentis are anti-VEGF drugs, although only Lucentis is approved by the U.S. Food and Drug Administration to treat AMD. A single dose of Lucentis costs nearly 40 times more than a single dose of Avastin.

“If value equals quality divided by cost, then the 1-year CATT study has indeed underscored the overall value of Avastin relative to Lucentis in the treatment of neovascular AMD,” Dr. Pohl said.

Anatomical findings

There were some differences in the anatomical outcomes of the CATT study, which evaluated both monthly and as-needed dosages of the two drugs.

Dr. Pohl said that Lucentis dosed monthly resulted in the greatest decrease in central retinal thickness. He said while these findings are noteworthy, their ultimate impact on vision remains to be seen.

“The ocular coherence tomography differences may or may not have an effect visually; that still has to be determined,” he said. “The second year CATT data should determine whether any visual acuity differences develop over another year, given that the OCT retinal thicknesses favored Lucentis.”

Systemic adverse events

Another area of the study in which Lucentis fared slightly better than Avastin was that of systemic adverse events. According to study data, the incidence of serious systemic adverse events was higher with Avastin (24%) than with Lucentis (19.0%).

“These events don’t appear to be associated with organ systems that were specific to anti-VEGF therapy, so it has been suggested by some authorities that there is insufficient evidence regarding serious adverse events at this point,” Dr. Pohl said. “However, I’ll be quick to add that the relative safety issue does need to be further addressed and confirmed.”

Dr. McCluskey added that it is difficult to link these adverse events to Avastin, given the potential comorbidities of the aging population.

“It would be one thing if these events were happening in 20-year-olds,” she said. “But in the age group that has AMD, it’s much less clear.”

She said she does not feel that these findings are a cause for alarm.

“I looked it over closely, and the difference does appear to be very small,” she said.

Financial agendas?

Dr. Pohl said that given the significant cost difference of the two drugs – which are made by the same company – the findings from this study are bound to be exploited for political and financial purposes.

“The financial and political threads are potentially intertwined in any clinical study,” Dr. Pohl said.

He said that although there may be attempts to leverage the findings in support of one drug or the other’s commercial success, he hopes the clinical implications will ultimately remain the primary focus.

“This study is unique in that it is a valid, clinical, evidence-based study – a large, multi-center study that carries with it excellent 1-year clinical information,” he said.

“The most important thing at this point is the clinical implications,” Dr. Pohl added. “The financial and political aspects are secondary. But, inevitably, they will have to be dealt with.”

Time will tell

Drs. Pohl and McCluskey both emphasized that despite the various motivations driving the use of one medication or the other, the study findings showed that both Avastin and Lucentis are good medications.

“The 1-year CATT study results affirm the use of either Lucentis or Avastin,” Dr. Pohl said. “Both drugs provided substantial improvements in visual acuity and prevented further loss of vision.”

Dr. McCluskey, who prescribes Avastin to most of her AMD patients, said she nevertheless would not want one drug to entirely eclipse the other.

Jessica McCluskey

“I prescribe Lucentis to my patients who don’t respond to Avastin, or who stop responding,” she said. “I wouldn’t want a situation where insurance providers start to only cover Avastin. I think it’s good to have them both as an option.”

She said although she feels confident prescribing Avastin to her patients, she can understand why doctors who prescribe Lucentis have not been compelled to switch.

“I think there hasn’t been much switching because the study showed that neither drug was superior to the other,” she said. “Therefore, retina specialists don’t want to change therapies if one is currently working for a patient.”

Dr. McCluskey added, however, that she is glad to be able to reference the study to her patients, who may be wary of Avastin due to articles in the lay press.

“Patients aren’t reading scientific journals, they’re reading publications like the New York Times,” she said. “So it’s nice to now have a study to show them, to address the concerns they might have.”

Dr. Pohl said that, ultimately, only time will tell whether there is a clear “winner” between these two or even others that are being developed.

“This is a chronic disease, and many of our patients will live 10 to 15 years beyond the 1 year we have results for,” he said. “Once we have long-term data, it will provide further justification, and one drug may become more widely available than the other. Until then, I think retinal specialists should continue to have access to both drugs without regulatory restrictions.” – by Jennifer Byrne

• Jessica McCluskey, MD, is a retina specialist at Thomas Eye Group in Atlanta. She can be reached at 5671 Peachtree Dunwoody Rd., Suite 400, Atlanta, GA 30342; (678) 892-2020; jdmccluskey1@yahoo.com.
• Maynard L. Pohl, OD, FAAO, practices at Pacific Cataract and Laser Institute in Bellevue, Wash. He can be reached at 10500 NE 8th St., Ste. 1650, Bellevue, WA 98004; (425) 462-7664; fax: (425) 462-6429; maynard.pohl@pcli.com.
• Disclosures: Neither Dr. McCluskey nor Dr. Pohl has any relevant financial disclosures.