FDA Grants Definium Breakthrough Designation for DT120 in Major Depression

Key Points

• The FDA granted Breakthrough Therapy designation to Definium Therapeutics’ DT120 orally disintegrating tablet for major depressive disorder.
• The designation follows positive Phase 3 Emerge study results, in which a single 100-microgram dose showed an 8.1-point placebo-adjusted improvement in depression scores at Week 6.
• Definium reported that the treatment effect remained durable through Week 12.
• DT120 has now received FDA Breakthrough Therapy designation in both major depressive disorder and generalized anxiety disorder.
• DT120 remains investigational and has not been approved by the FDA.

Definium Therapeutics (NASDAQ: DFTX) has been granted Breakthrough Therapy designation by the U.S. Food and Drug Administration for DT120, an investigational orally disintegrating tablet formulation of lysergide for major depressive disorder, or MDD.

The designation marks the second FDA Breakthrough Therapy designation for the DT120 development program. The FDA previously granted the designation to DT120 for the potential treatment of generalized anxiety disorder, or GAD.

Phase 3 Emerge Data Supported FDA Designation

Definium said the FDA based its decision on the unmet need in major depressive disorder and results from the company’s Phase 3 Emerge study.

In the trial, a single 100-microgram dose of DT120 produced a statistically significant 8.1-point placebo-adjusted improvement on the Montgomery-Åsberg Depression Rating Scale, or MADRS, at Week 6. The company reported a p-value of less than 0.0001.

Definium also said the treatment showed durable efficacy through Week 12.

MADRS is a clinician-rated scale used to evaluate the severity of depressive symptoms. The placebo-adjusted result reflects the difference between outcomes in the DT120 treatment group and those in the placebo group.

Second Breakthrough Designation Expands DT120’s Regulatory Support

Breakthrough Therapy designation is intended to help speed the development and review of medicines designed for serious conditions when preliminary clinical evidence suggests the therapy may provide substantial improvement over available treatments on one or more clinically meaningful measures.

The new designation places DT120 in the Breakthrough Therapy program for both MDD and GAD. Definium said the dual designations reflect the company’s effort to develop the therapy across serious mental health conditions with significant unmet need.

The designation does not represent FDA approval. Definium must continue development and complete the regulatory review process before DT120 could become available to patients.

Major Depression Remains a Large Unmet Need

Major depressive disorder is characterized by at least five depressive symptoms that persist for two weeks or longer. Symptoms can include feelings of worthlessness, fatigue, impaired social functioning, and recurrent thoughts of death.

More than 21 million U.S. adults experience a major depressive episode each year, according to the company. Definium said MDD is the second-most common mental health disorder in the U.S. and a leading cause of disability worldwide.

Despite available first-line treatments, fewer than one-third of patients achieve remission, underscoring the need for additional treatment options.

What Comes Next for Definium and DT120

The designation may allow Definium to work more closely with the FDA as it advances DT120. However, the announcement does not provide an FDA filing timeline, anticipated approval date, or commercial-launch target.

For investors, future developments will include additional clinical data, regulatory discussions, and details on Definium’s planned path toward a potential New Drug Application. The company will also need to establish the safety and benefit-risk profile of DT120 through the FDA review process.