COPHy 2026: Treat-and-extend in the era of sustained drug delivery

At the 17th annual Congress on Controversies in Ophthalmology (COPHy) held 20-21 March 2026, in Krakow, Poland, Prof. Anat Loewenstein presented the “no” position on whether treat-and-extend will remain the preferred treatment strategy in the era of sustained drug delivery for retinal diseases.

Drawing on experience across age-related macular degeneration, diabetic retinopathy, and vein occlusion with macular oedema, Loewenstein noted that clinicians have “learned to adapt the treat and extend regimen” over time, with outcomes comparable to PRN approaches in terms of injection burden. Specifically, “the number of injections is not different than when you use the PRN approach,” although visit frequency may be reduced because “every visit is an injection,” she said. Loewenstein is professor at Tel Aviv Sourasky Medical Center - Ichilov in Tel Aviv, Israel.

She added that evolving therapeutic modalities are shifting this paradigm. With the emergence of sustained delivery systems and longer-acting agents, including regimens with fixed dosing intervals such as “every six months,” the traditional logic of incremental extension becomes less relevant. As she noted, “the treat and extend might not be the best way to go,” particularly when therapies are designed to maintain efficacy over prolonged intervals without frequent reassessment.

Loewenstein further highlighted that even among newer anti-VEGF agents without slow-release devices, such as higher-dose formulations, clinicians may not need to follow a strict treat-and-extend framework. Instead, after a loading phase, physicians may “just extend, try and extend it,” resulting in an approach that “is actually switched to be more of a PRN approach.” This reflects a broader shift away from rigid interval adjustment toward more flexible or response-driven strategies.

Emerging modalities and clinical implications

A central component of her argument involves the role of emerging technologies and delivery systems. Home optical coherence tomography (OCT), for example, introduces a paradigm of continuous monitoring with automated alerts: “whenever there is a little fluid, an alert is sent to the patient and to the physician.” In this context, treatment becomes “more of a PRN… a real PRN,” potentially enabling earlier detection and intervention while reducing unnecessary visits.

She also pointed to ongoing research, including Protocol AO of the DRCR Network, which aims to determine whether such “very, very accurate PRN” approaches can achieve “better final outcome and/or less injections” compared to treat-and-extend. These data may further inform whether traditional regimens remain appropriate in the setting of enhanced monitoring and longer-acting therapies.

In comparing strategies, Loewenstein noted that treat-and-extend was developed in the context of earlier anti-VEGF agents, whereas newer drugs and modalities offer different pharmacologic profiles. Although efficacy outcomes may be “very similar,” extended dosing intervals and reduced treatment burden are increasingly achievable. In the case of tyrosine kinase inhibitors (TKIs), which “has the potential to hold for many months,” she noted directly that “treat and extend is not really relevant.”

From a practical standpoint, she acknowledged that treat-and-extend has demonstrated improved compliance compared with traditional PRN regimens. However, longer-acting therapies may further reduce adherence challenges: “the issue of compliance becomes much easier if you are looking into a treatment that will be given every four, five, six, or nine months even.” At the same time, she noted ongoing logistical considerations, including the need for periodic follow-up and safety monitoring, potentially supported by technologies such as Home OCT.

Ultimately, Loewenstein concluded that sustained drug delivery and related innovations are likely to displace treat-and-extend as a dominant paradigm. With therapies that can be administered “once every nine months, once a year, and even longer,” clinicians are no longer “giving something and then extending,” but instead initiating durable treatment upfront. In this context, “the treat and extend methodology becomes a little… obsolete,” reflecting a broader transition in retinal disease management toward longer-acting, lower-burden care models.