ACD856

ACD856
Clinical data
Other namesACD-856
Routes of
administration		Oral
Drug classTropomyosin receptor kinase TrkA, TrkB, and TrkC positive allosteric modulator
Pharmacokinetic data
Elimination half-life~19 hours

ACD856, or ACD-856, is a tropomyosin receptor kinase TrkA, TrkB, and TrkC positive allosteric modulator which is under development for the treatment of Alzheimer's disease, depressive disorders, sleep disorders, and traumatic brain injuries. It is taken by mouth.

Pharmacology

The drug potentiates the tropomyosin receptor kinases TrkA, TrkB, and TrkC with EC50Tooltip half-maximal effective concentration values of 382 nM, 295 nM, and ~330 nM, respectively. As a positive allosteric modulator of TrkA and TrkB, ACD856 potentiates the effects of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF).

In addition to the tropomyosin receptor kinases, ACD856 is also a similarly potent positive allosteric modulator of certain other receptor tyrosine kinases, including the insulin-like growth factor 1 receptor (IGF1R) and the fibroblast growth factor receptor 1 (FGFR1). However, its efficacies at the IGF1R and FGFR1 were much lower than at the TrkA, TrkB, and TrkC.

In animals, ACD856 has been found to reverse scopolamine- and dizocilpine (MK-801)-induced memory impairment, to improve age-related memory deficits, and to have sustained antidepressant-like activity. It has also been reported to possess neuroprotective properties.

In humans, the drug has been shown to cross the blood–brain barrier and to induce dose-dependent changes in electroencephalogram parameters. No significant tolerability or safety concerns have been identified in preclinical research or phase 1 clinical trials. The drug's clinical pharmacokinetics have been characterized and its elimination half-life is approximately 19 hours.

Chemistry

The chemical structure of ACD856 has not yet been disclosed as of 2024, but the structure of its predecessor ponazuril (ACD855) is known and both ponazuril and ACD856 have been described as triazinetriones.

History

It was discovered through the use of high-throughput screening of 25,000 compounds. Toltrazuril and ponazuril (ACD855), two veterinary antiparasitic agents, were identified as possessing Trk-potentiating activity with this screen in 2013. ACD856 was derived via structural optimization of these compounds. In the case of ponazuril, this drug was said to have had too long of an elimination half-life to allow for development for use in humans. ACD856 was first described in the scientific literature by 2021.

Clinical trials

ACD856 has completed phase 1 clinical trials for Alzheimer's disease. As of May 2024, it was in the preclinical stage of development for depressive disorders, sleep disorders, and traumatic brain injuries. Two phase 1 trials had been completed by 2022. A further phase 1b trial, assessing the safety and tolerability of repeated higher doses, reached its last patient visit in April 2026, and results were reported in June 2026. A phase 2 clinical trial in Alzheimer's disease was expected to start in 2026, supported by a €2.5 million European Innovation Council Accelerator grant awarded in 2025. The drug was developed by AlzeCure Pharma AB, which in July 2026 out-licensed worldwide rights to ACD856 and the NeuroRestore platform to the Danish company QuantumCell ApS for US$12 million upfront, with development and commercial milestone payments that could exceed US$2.2 billion.

References

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  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 "ACD856". ALZFORUM. 19 December 2023. Retrieved 23 October 2024.
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  6. 1 2 Wang D, Lang ZC, Wei SN, Wang W, Zhang H (2 May 2024). "Targeting brain-derived neurotrophic factor in the treatment of neurodegenerative diseases: A review". Neuroprotection. 2 (2). Wiley: 67–78. doi:10.1002/nep3.43. ISSN 2770-7296. ACD856 is an innovative allosteric modulator that positively affects all Trk receptors, amplifying their kinase activity. Subsequently, it potentiates the effect of BDNF or nerve growth factor (NGF) on neuronal survival, function, and plasticity of synapses. The finished phase I study showed that ACD856 passed the blood‐brain barrier and induced dose‐dependent treatment‐related alterations in quantitative electroencephalogram parameters with good safety.141,142
  7. 1 2 3 4 Parrado Fernandez C, Juric S, Backlund M, Dahlström M, Madjid N, Lidell V, et al. (July 2023). "Neuroprotective and Disease-Modifying Effects of the Triazinetrione ACD856, a Positive Allosteric Modulator of Trk-Receptors for the Treatment of Cognitive Dysfunction in Alzheimer's Disease". International Journal of Molecular Sciences. 24 (13) 11159. doi:10.3390/ijms241311159. PMC 10342804. PMID 37446337.
  8. ↑ Madjid N, Lidell V, Nordvall G, Lindskog M, Ögren SO, Forsell P, et al. (August 2023). "Antidepressant effects of novel positive allosteric modulators of Trk-receptor mediated signaling - a potential therapeutic concept?". Psychopharmacology. 240 (8): 1789–1804. doi:10.1007/s00213-023-06410-x. PMC 10349764. PMID 37394539.
  9. 1 2 Önnestam K, Nilsson B, Rother M, Rein-Hedin E, Bylund J, Anderer P, et al. (2023). "Safety, Tolerability, Pharmacokinetics and Quantitative Electroencephalography Assessment of ACD856, a Novel Positive Allosteric Modulator of Trk-Receptors Following Multiple Doses in Healthy Subjects". The Journal of Prevention of Alzheimer's Disease. 10 (4): 778–789. doi:10.14283/jpad.2023.89. PMID 37874100.
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  11. 1 2 Nilsson B, Bylund J, Halldin MM, Rother M, Rein-Hedin E, Önnestam K, et al. (May 2024). "ACD856, a novel positive allosteric modulator of Trk receptors, single ascending doses in healthy subjects: Safety and pharmacokinetics". European Journal of Clinical Pharmacology. 80 (5): 717–727. doi:10.1007/s00228-024-03645-1. PMC 11001683. PMID 38353689.
  12. ↑ Nordvall G, Madjid N, Backlund M, Halldin M, Rother M, Nilsson B, et al. (2021). "ACD856: A novel positive allosteric modulator of Trk-signaling in clinical development for the treatment of Alzheimer's disease". Alzheimer's & Dementia. 17 (S9) e057730. Wiley. doi:10.1002/alz.057730. ISSN 1552-5260.
  13. 1 2 3 Taylor NP (1 July 2026). "Backed by top-tier VCs, stealthy biotech bags AlzeCure Alzheimer's asset in $2.2B deal". Fierce Biotech. Retrieved 25 July 2026.
  14. ↑ "Last patient has completed AlzeCure's Phase Ib clinical study with NeuroRestore ACD856" (Press release). AlzeCure Pharma AB. 20 April 2026. Retrieved 25 July 2026.
  15. 1 2 "Positive results from the Phase Ib clinical study of NeuroRestore ACD856, under development for Alzheimer's" (Press release). AlzeCure Pharma AB. 16 June 2026. Retrieved 25 July 2026.
  16. ↑ "AlzeCure receives EU grant for Phase 2 clinical trial of NeuroRestore ACD856 for Alzheimer's disease" (Press release). AlzeCure Pharma AB. 17 February 2025. Retrieved 25 July 2026.
  17. ↑ Pinching J (1 July 2026). "AlzeCure enters collaboration agreement with QuantumCell ApS for NeuroRestore project". PharmaTimes. Retrieved 25 July 2026.