Aldeyra Therapeutics Inc. ( ALDX ) shares are tumbling on Tuesday following the U.S. Food and Drug Administration (FDA) update.

The company received an FDA Complete Response Letter (CRL) regarding its New Drug Application for reproxalap, an investigational treatment for dry eye disease.

FDA Cites Lack Of Evidence

The CRL stated that there is “a lack of substantial evidence consisting of adequate and well-controlled investigations.”

The CRL indicated that Aldeyra failed to provide substantial evidence demonstrating the efficacy of reproxalap in adequately controlled studies, raising significant concerns about the reliability of positive findings.

The FDA did not recommend further trials but suggested exploring the reasons for the failures in certain trials and identifying specific populations where the drug may be effective.

In a statement, Aldeyra’s CEO, Todd Brady, emphasized the urgency of working with the FDA to enable market access for reproxalap, viewing it as a potential breakthrough treatment for dry eye disease.

Aldeyra Cash Runway Into 2028

As of December 31, 2025, the company reported having $70 million in cash and equivalents, expected to support operations into 2028.

NDA Review Background And Prior FDA Actions

After the company submitted the NDA on June 16, the FDA accepted it for review as a “complete class 2 response” on July 16, 2025, and set a target PDUFA action date of December 16.

The FDA extended the Prescription Drug User Fee Act (PDUFA) target action date (decision date) for reproxalap to March 16, 2026.

Aldeyra Previous FDA Rejections

In April 2025, the FDA issued a Complete Response Letter for Aldeyra’s resubmission of the reproxalap application.

That time, the FDA stated that the NDA “failed to demonstrate efficacy in adequate and well-controlled studies in treating ocular symptoms associated with dry eyes” and that “at least one additional adequate and well-controlled study to demonstrate a positive effect on the treatment of ocular symptoms of a dry eye” should be conducted.

In November 2023, the FDA issued a Complete Response Letter to the initial NDA stating that at least one additional symptom trial was required.

ALDX Price Action: Aldeyra Therapeutics ( ALDX ) shares were down 68.61% at $1.32 at the time of publication on Tuesday. The stock is near its 52-week low of $1.13, according to Benzinga Pro data.

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