Name: HTL0018318
Therapy Type: Small Molecule (timeline)
Target Type: Cholinergic System (timeline)
Condition(s): Alzheimer's Disease, Dementia with Lewy Bodies
U.S. FDA Status: Alzheimer's Disease (Inactive), Dementia with Lewy Bodies (Inactive)
Company: Allergan plc, Sosei Heptares


This small-molecule drug selectively activates the muscarinic acetylcholine receptor M1, which is expressed in the central nervous system and peripheral secretory glands. HTL0018318 was developed by Heptares Therapeutics, a subsidiary of the Sosei Group Corporation, headquartered in Tokyo. Allergan Pharmaceuticals, headquartered in Dublin, licensed the rights to it in 2016. The companies were jointly developing this compound as a symptomatic treatment for the cognitive deficits in Alzheimer’s disease.


In 2015 and 2016, Heptares ran two Phase 1 trials of HTL0018318 in Japan, in 84 and 28 participants, respectively. In 2016 and 2017, Heptares ran two Phase 1 trials in London, one to evaluate bioavailability of doses up to 35 mg in 40 healthy volunteers, and one to study single and multiple dose administration in 57 healthy elderly volunteers. Results of both trials are published. The drug was well-tolerated in single doses, and in multiple doses up to 25 mg. Cholinergic adverse events included nausea, sweating, and increased blood pressure and heart rate, especially at higher doses and in elderly participants. Pharmacokinetics were dose-proportional, and CSF concentrations reached 30 percent of blood levels. Single and multiple doses were associated with some improvements on tests of working memory and learning (Bakker et al., 2020; Bakker et al., 2021). In 2018, Heptares ran a Phase 1b study in four European countries, comparing three doses to placebo given for four weeks in 60 AD patients as an add-on to standard of care.

In July 2018, Heptares listed a 12-week Phase 2 trial in Japan. It was designed to compare three doses of HTL0018318 against placebo in 172 people with dementia with Lewy bodies (DLB) who have never taken, or have stopped taking, acetylcholinesterase inhibitors. Measuring safety, cognitive impairment, and psychosis as outcomes, the trial was to start in August 2018; however, on September 18, 2018, Allergan and Sosei announced they were delaying this trial due to toxicology findings in nonhuman primates. In a nine-month dose-finding study, some animals developed tumors at doses higher than those used in humans. The companies have suspended development of HTL0018318, including a planned Phase 2 study in AD, while they investigate, but claimed that no serious adverse effects have emerged in the 310 people who have taken the drug so far (see company press release).

In May 2020, AbbVie acquired Allergan. In January 2021, AbbVie terminated the licensing agreement, and returned to Sosei Heptares all rights to HTL0018318 and other muscarinic agonists (press release).

Last Updated: 07 May 2021


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Paper Citations

  1. . First-in-man study to investigate safety, pharmacokinetics and exploratory pharmacodynamics of HTL0018318, a novel M1 -receptor partial agonist for the treatment of dementias. Br J Clin Pharmacol. 2020 Dec 22; PubMed.
  2. . Safety, pharmacokinetics and exploratory pro-cognitive effects of HTL0018318, a selective M1 receptor agonist, in healthy younger adult and elderly subjects: a multiple ascending dose study. Alzheimers Res Ther. 2021 Apr 21;13(1):87. PubMed.

External Citations

  1. company press release
  2. press release

Further Reading

No Available Further Reading