Wet age-related macular degeneration (wAMD), the top cause of blindness for people over 65, now has a clear treatment trend of administering a small number of injections, while maintaining the efficacy of the treatment, Bayer Korea said.

Professor Woo Sae-joon at Seoul National University Bundang Hospital explains the benefits of T&E therapy for treating wAMD, during a news conference at the JW Marriott Dongdaemun Square Seoul on Thursday.

Recently, as the elderly population continues to increase, the number of patients with macular degeneration is also increasing.

"Treatment for macular degeneration requires long-term or lifetime treatment," Professor Woo Sae-joon at Seoul National University Bundang Hospital said in a news conference Thursday. "However, Anti-VGEF injections must be injected directly into the eye, while conventional drugs used to treat wAMD have a short therapeutic effect of one to two months."

Therefore, hospitals have tried to reduce the number of injections and maintain the effect to be advantageous in terms of cost, Woo added.

Pharmaceutical firms have also been making various attempts to maintain the effect, while increasing the dosing interval than the fixed period identified in the licensed clinical trial. Such efforts have led to new therapy methods, such as the PRN (Pro re nata) and T&E (Treat and Extend) therapy.

The PRN therapy, developed to overcome these limitations, evaluates the patient's risk of recurrence through monthly monitoring to determine whether to administer it.

"PRN therapy can reduce the monthly injections by half," Woo said. "In the real world, however, the therapy failed to show the effect as expected, regardless of the administration interval, due to the monthly monitoring burden."

As wAMD visually impairs the patient after a certain period after recurrence, patients may not be able to cure their symptoms if they do not receive treatment within an appropriate time, he added.

Woo stressed that if the monitoring interval is longer than one month, it can reduce its therapeutic effect. Also, PRN therapy has a risk of under-treatment as treatment is determined after the patient's condition worsens.

On the contrary, T&E therapy is an attempt to find a dosing cycle suitable for each individual by expanding the dosing interval by focusing on the fact that the recurrence cycle varies from patient to patient due to the nature of wAMD.

Unlike PRN therapy, the methods preemptively administer the drug before the patient's relapse occurs, which, in turn, lowers the risk of recurrence. The number of hospital visits can be reduced as hospitals can minter the patient while administrating the drug.

To this end, Bayer's Eylea has demonstrated the effectiveness of T&E therapy through ALTAIR research and received additional approval to flexibly extend the dosing interval from two months to four months in 2018.

In the ALTAIR study, more than 40 percent of clinical participants managed to keep their dosing intervals 16 weeks apart. During the second year of the trial, the average number of drug administration for patients per year was 3.6 to 3.7 times, which was less than the fixed cycle therapy of four times.

"What is more meaningful is that unlike fixed-cycle therapy, which has the possibility of excessive or under-treatment due to different recurrence cycles for different patients, T&E therapy can be customized for individual treatment," Professor Woo said. "Ideally, wAMD can be best treated by finding individual intervals depending on the patient."

To this end, Eylea has a wide variety of approaches, from a minimum of two months to a maximum of four months, Woo added.

Woo also stressed that the T&E therapy method is optimal during the current Covid-19 outbreak.

"In recent times, Covid-19 has reduced the number of hospital visits for patients," he said. "Therefore, major guidelines from around the world are currently recommending T&E therapy."

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