Tonix could get 2019 nod for breakthrough-badged PTSD therapy: analysts

The FDA has said only one trial may be needed if the data are "persuasive."

Just as global security is starting to look a bit precarious, Tonix Pharmaceuticals has started recruiting military personnel into a phase 3 trial of its drug candidate for combat-related post-traumatic stress disorder (PTSD).

The drug—code-named TNX-102 SL—is a fast-dissolving, under-the-tongue formulation of cyclobenzaprine, a drug that is already FDA-approved as a muscle relaxant. Tonix reported positive results from a phase 2 trial last year suggesting it could alleviate PTSD symptoms such as disturbed sleep and nightmares, earning it a breakthrough designation from the FDA last December.

While there are approved antidepressant and anxiety medicines for the estimated 7 million to 8 million Americans who experience PTSD in a 12-month period, they are not considered very effective and can cause troublesome side effects. TNX-102 SL is thought to help restore healthy sleep that in turn aids the body's natural recovery from severe trauma.

Tonix needs the PTSD program to deliver after a string of pipeline disappointments, including the demise of a chronic headache candidate in phase 2 last year and TNX-102 SL's failure to show efficacy in a phase 2b trial in fibromyalgia in 2014.

The HONOR trial of TNX-102 SL will enroll 550 PTSD sufferers and, according to analysts at Edison, the FDA has agreed to an interim analysis after data on half that recruitment target is available, expected in the first half of next year.

"The FDA has also indicated that if the data is 'statistically persuasive' only one study may be needed for approval," say Edison's Maxim Jacobs and Nathaniel Calloway in a research note. With the BTD giving a possible six-month FDA review period and the potential for an early trial halt, "approval is possible in 2019," they suggest, while still projecting a green light in 2020.

TNX-102 SL is not the first older compound that is being rejigged as a possible PTSD treatment. The FDA recently gave the go-ahead to a large-scale trial of MDMA—also known as Ecstasy—after encouraging signals in smaller trials. And last year Marina Biotech bought rights to an intranasal ketamine derivative for PTSD from Turing Pharma that is in late-stage development for PTSD.

Other companies working on novel drugs in this area include Chronos Therapeutics, which has a tropomyosin receptor kinase B drug at the lead generation stage, and Allergan spinout Aptinyx with NMDA modulators in preclinical development.