FDA Denies Approval of Reproxalap for Dry Eye Disease (Again)

For the third time, the U.S. Food and Drug Administration (FDA) has declined to approve reproxalap, an investigational drug developed by Aldeyra Therapeutics, for the treatment of dry eye disease. The decision, communicated in a complete response letter, centers on a lack of “substantial evidence” demonstrating the drug’s efficacy, despite finding no concerns regarding its safety or manufacturing processes. This latest setback for Aldeyra and patients seeking novel treatment options for this common condition raises questions about the path forward for reproxalap and the challenges in developing effective therapies for dry eye.

What the FDA Found

According to a press release issued by Aldeyra Therapeutics on March 18, 2026, the FDA’s complete response letter specifically cited an “inconsistency of study results” that raised “serious concerns about the reliability and meaningfulness of the positive findings.” While the agency did not identify any issues with the safety profile or how the drug was manufactured, the lack of consistent efficacy data proved to be a critical hurdle. This isn’t the first time the FDA has raised concerns about reproxalap’s efficacy. Aldeyra received a similar complete response letter in April 2025 after resubmitting its new drug application, and a first rejection occurred prior to that.

The FDA’s decision follows Aldeyra’s third submission of a new drug application for reproxalap in July 2025. The drug is designed to address the inflammatory aspects of dry eye disease by modulating the activity of a protein called reactive aldehyde species (RAS). RAS are elevated in the tears of individuals with dry eye and are believed to contribute to the symptoms of the condition.

Dry Eye Disease: A Common and Often Debilitating Condition

Dry eye disease, also known as keratoconjunctivitis sicca, is a prevalent condition affecting millions of people worldwide. It occurs when the eyes don’t produce enough tears or the tears are of poor quality, leading to discomfort, irritation, and potential vision problems. Symptoms can range from mild dryness and burning to severe pain and blurred vision. The Tear Film & Ocular Surface Society (TFOS) Dry Eye Workshop III, a comprehensive review of the latest research, highlights the multifactorial nature of the disease, involving tear film dysfunction, inflammation, and hyperosmolarity.

Current treatments for dry eye disease include artificial tears, prescription eye drops that reduce inflammation (like cyclosporine and lifitegrast), and procedures to block tear drainage. However, many patients do not locate sufficient relief with these options, creating a need for new and more effective therapies. Reproxalap aimed to offer a novel approach by directly targeting RAS, potentially providing faster and more sustained symptom relief.

Understanding the Clinical Trial Data

The clinical development program for reproxalap included several Phase 2 and Phase 3 clinical trials. While some studies showed promising results, demonstrating improvements in key dry eye symptoms, others yielded less conclusive findings. The FDA’s concerns appear to stem from the inconsistencies across these trials, making it difficult to confidently establish the drug’s efficacy.

It’s important to note that clinical trials are complex endeavors, and variability in study results is not uncommon. Factors such as patient selection, study design, and the utilize of different outcome measures can all contribute to inconsistencies. The FDA requires substantial evidence from well-controlled trials to demonstrate that a drug is both safe and effective before it can be approved for marketing.

Aldeyra’s Response and Future Plans

Despite the FDA’s latest rejection, Aldeyra Therapeutics remains committed to pursuing approval for reproxalap. Todd C. Brady, MD, PhD, president and CEO of Aldeyra, stated that the company “will work with urgency” to address the FDA’s concerns and provide the agency with the information needed to support market access. The company plans to collaborate with the FDA to determine the best path forward, which may involve conducting additional clinical trials or submitting further data analysis.

Aldeyra emphasized that, to their knowledge, reproxalap is the only drug in development that demonstrates clinical activity within minutes of administration in patients with dry eye disease. This rapid onset of action could be a significant advantage over existing treatments, which often require weeks or months to demonstrate noticeable improvement.

What So for Patients

The FDA’s decision is undoubtedly disappointing for patients with dry eye disease who were hoping for a new treatment option. However, it’s important to remember that this does not imply reproxalap will never be approved. The FDA’s process is rigorous, and the agency’s goal is to ensure that all approved drugs are safe and effective.

Patients with dry eye disease should continue to work with their eye care professionals to manage their symptoms using currently available treatments. It’s also important to maintain good eye hygiene, avoid environmental irritants, and consider lifestyle modifications that can support alleviate symptoms.

The Regulatory Pathway Forward

The FDA’s rejection of reproxalap highlights the challenges inherent in drug development, particularly for complex conditions like dry eye disease. The agency’s focus on substantial evidence of efficacy underscores the importance of well-designed and rigorously conducted clinical trials. Aldeyra will likely need to address the FDA’s concerns regarding the consistency of its clinical data, potentially through additional studies or a refined analysis of existing data.

The FDA’s review process typically involves several stages, including a preliminary review of the application, a detailed evaluation of the clinical and non-clinical data, and potentially an advisory committee meeting to gather expert opinions. The agency may also request additional information from the drug sponsor during the review process. The timeline for a potential re-submission and subsequent review of reproxalap remains uncertain.

For more information on dry eye disease and available treatments, patients can consult with their eye care professional or visit the website of the American Academy of Ophthalmology. Updates on the development of reproxalap can be found on the Aldeyra Therapeutics website. The FDA also provides information on drug approvals and regulatory processes on its website.