The US Food and Drug Administration (FDA) has granted an orphan drug designation to Actimed Therapeutics’ S-oxprenolol (ACM-002) for the treatment of amyotrophic lateral sclerosis (ALS).

The UK-based pharma company will now be in line for tax credits for US-based clinical trials, and if the therapy is approved, the potential for seven years of market exclusivity in the designated indication, as per a 4 September press release.

Actimed says S-oxprenolol shares “a similar pharmacology” to S-pindolol, which is an anabolic/catabolic transforming agent. S-pindolol benzoate, Actimed’s lead product, is being investigated for the treatment of the metabolic weight loss syndrome called cachexia.

With S-oxprenolol, Actimed is targeting S-pindolol’s mechanistic approach in the wasting syndrome to address the loss of body mass and muscle wasting seen in ALS.

ALS is the most common form of motor neuron disease. Muscle wasting is seen in patients as motor neuron degeneration means muscles no longer receive electrical signals.

There are currently six FDA-approved therapies for ALS, though the agency has developed a five-year plan to accelerate the development of more treatments and improve medicine access.

There have been a few recent setbacks in the space, including Amylyx Pharmaceutical’s Phase III failure and Ionis/Biogen's decision to discontinue the development of their ALS candidate.

In preclinical ALS models, S-oxprenolol has demonstrated an ability to attenuate muscle loss, improve lean body mass, and reduce the loss of overall body mass, amongst other benefits.

Oxprenolol is a beta blocker usually used for the treatment of heart conditions such as angina and high blood pressure. While Actimed has not disclosed the mechanism of action in ALS, the related compound S-pindolol increases anabolism and muscle by partial beta-2 receptor agonism.

Actimed is currently conducting trials for S-pindolol in cancer cachexia, a sub-type of the syndrome found in cancer patients. The compound has demonstrated positive proof of concept data in a Phase IIa study, with further clinical trials planned according to the company.

Actimed has yet not unveiled details of a clinical programme for S-oxprenolol. Nonetheless, the company has already licensed the drug’s global rights for cancer cachexia and non-ALS indications to US company Faraday Pharmaceuticals. The deal, signed in 2021, included an upfront payment of $550,000 and $126.2m in milestone payments.

Actimed’s CEO Robin Bhattacherjee said: “The early non-clinical data we have generated for S-oxprenolol in this indication suggest that it could have a potential role in meeting some of the important needs of this under-served patient population.”