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Synthetic

AJAAjulemic acid (lenabasum)

A synthetic analogue of THC-11-oic acid, with a CB2 preference; its phase 3 trial in scleroderma did not meet its primary endpoint.

FranceNarcotic: generic clauseInternationalUnscheduled
Level of detail

Harm-reduction warning

No characterised human dose: animal / in vitro data only. Effect profile, safety margin and acute toxicity are not documented in human clinical practice. Extremely potent compound: severe effects, seizures and deaths reported in the literature.

C₂₅H₃₆O₄

CAS 137945-48-3

Family
Synthetic CB receptor agonistResearch ligand or medicine
Molar mass
400.60 g/mol

Updated on

In plain terms

Ajulemic acid, also called lenabasum, is a laboratory molecule made from a metabolite of THC. It was studied as a medicine for inflammation. At the target dose used in trials, cannabis users did not like it, but higher doses were liked. Its large trials did not reach their goal and it was never marketed.

Receptors and activity

Target network

CB2Agonistno measured value
  • Activates
  • Binds or modulates

The lower the cited value, the closer the target sits to AJA: one ring per factor of 100. A target with no measured value stays on the edge.

Where these targets live

Where each target has been found in humans, according to the cited studies. The map shows the target, not an effect of AJA.

Brain, side view
Body, front view
Blood

CB2CB2 found in 5 regions of the body

  1. SpleendenseHighly abundant in the spleen1
  2. Immune cellspresentMainly B cells and natural killer cells1
  3. SkinpresentKeratinocytes, mast cells and nerve fibres2
  4. GutpresentImmune cells of the colonic mucosa3
  5. BonepresentPresent on osteoclasts4

Map sources

  1. Galiègue S et al. Expression of central and peripheral cannabinoid receptors in human immune tissues and leukocyte subpopulations. Eur J Biochem, 1995 (new tab)
  2. Ständer S et al. Distribution of cannabinoid receptor 1 (CB1) and 2 (CB2) on sensory nerve fibers and adnexal structures in human skin. J Dermatol Sci, 2005 (new tab)
  3. Wright K et al. Differential expression of cannabinoid receptors in the human colon: cannabinoids promote epithelial wound healing. Gastroenterology, 2005 (new tab)
  4. Rossi F et al. The endovanilloid/endocannabinoid system in human osteoclasts: possible involvement in bone formation and resorption. Bone, 2009 (new tab)

Cited values

  1. CB2Agonistno measured value cited
  2. CB1Binding (function not established)no measured value cited
  3. PPARγPartial agonistno measured value cited
Bar length follows the measured value (Ki, Kd, EC50 or IC50), on one scale shared by every entry, from 100 µM to 0.1 nM. A target with no cited value has no bar.

Pharmacology

Ajulemic acid (lenabasum) is a synthetic analogue of Δ8-THC-11-oic acid: the same benzo[c]chromene skeleton, with a 1,1-dimethylheptyl side chain in place of the pentyl and a carboxylic acid function at position 9 (Tepper et al. 2014, PMID 24856183). It acts as a cannabinoid agonist with a CB2 preference: the CB1/CB2 affinity ratio is 12.3 for the highly purified preparation JBT-101 against 0.19 for the original preparation HU-239 (Tepper 2014). In the model proposed by Burstein (Mol Pharmacol 2021, PMID 33239333), CB2 activation leads to the production of 15-deoxy-prostaglandin J2 and lipoxin A4; it also binds PPARγ, of which it is a partial agonist (Ambrosio et al. 2007, PMID 17462987). The clinical record is negative: the phase 3 trial RESOLVE-1, run in 365 patients with diffuse systemic sclerosis, did not meet its primary endpoint (CRISS score at week 52: 0.888 against 0.887 with placebo; Spiera et al. 2023, PMID 37098795), and a phase 2b trial in 447 people with cystic fibrosis did not reduce the rate of pulmonary exacerbations (West et al. 2025, PMID 40425421). In an abuse-potential study in 56 recreational cannabis users, the target dose did not increase liking of the product compared with placebo, whereas two supratherapeutic doses did so in a dose-dependent way, less than nabilone (Luba et al. 2024, PMID 38936978).

Key sources.

History

Source
An entirely synthetic molecule, designed in the laboratory as an analogue of a THC metabolite. It is not produced by hemp and has never been isolated from a plant.

Origin

Laboratory synthesis

No known biosynthetic pathway: ajulemic acid is a synthetic analogue of Δ8-THC-11-oic acid (Tepper et al. 2014). Compared with THC, the pentyl chain at position 3 is replaced by a branched 1,1-dimethylheptyl chain and the methyl at position 9 by a carboxylic acid function. Tepper and colleagues compared the original preparation (HU-239) with a highly purified one (JBT-101): CB2 affinity varied little between samples, CB1 affinity varied widely.

Classification

Family, origin and source verification

Family

Synthetic CB receptor agonist › Research ligand or medicine

Class

classical

Verification

Checked on 20 October 2026; some points still await human review.

Wikipedia (English)

Lenabasum (new tab)

Article paired by the molecule's structure (InChIKey), revision read on 19 October 2026. Read as a second opinion, never cited as a source.

References

  1. Burstein et al., J Med Chem 1992: non-psychotropic synthetic cannabinoid acids (new tab)PMID 1507202
  2. Tepper, Zurier & Burstein, Bioorg Med Chem 2014: highly purified ajulemic acid, CB2 selectivity (new tab)PMID 24856183
  3. Burstein, Mol Pharmacol 2021: molecular mechanisms of inflammation resolution by lenabasum (new tab)PMID 33239333
  4. Ambrosio et al., J Biol Chem 2007: structure of PPARγ in complex with ajulemic acid (new tab)PMID 17462987
  5. Fu et al., Eur J Drug Metab Pharmacokinet 2021: physiologically based pharmacokinetic model of lenabasum (new tab)PMID 34143391
  6. Luba et al., J Pharmacol Exp Ther 2024: abuse potential of lenabasum in 56 recreational cannabis users (new tab)PMID 38936978
  7. Spiera et al., Arthritis Rheumatol 2023: phase 3 RESOLVE-1 trial (new tab)PMID 37098795
  8. West et al., J Cyst Fibros 2025: phase 2b trial in cystic fibrosis (new tab)PMID 40425421
  9. PubChem CID 3083542: lenabasum (ajulemic acid), identifiers and properties (new tab)
  10. ANSM: consolidated list of substances classified as narcotics, updated 16/02/2026 (generic benzo[c]chromene clause, annex IV) (new tab)
  11. ANSM: decision of 22/05/2024 amending the list of substances classified as narcotics (new tab)

Identifiers

Names

Common name
Ajulemic acid (lenabasum)
IUPAC name
(6aR,10aR)-1-hydroxy-6,6-dimethyl-3-(2-methyloctan-2-yl)-6a,7,10,10a-tetrahydrobenzo[c]chromene-9-carboxylic acid
Other names
Ajulemic acid · Lenabasum · Anabasum · CT-3 · IP-751 · HU-239 · JBT-101 · CPL-7075 · Resunab

Identifiers

Formula
C₂₅H₃₆O₄
CAS
137945-48-3
PubChem CID
3083542(new tab)
InChIKey
YCHYFHOSGQABSW-RTBURBONSA-N
SMILES
CCCCCCC(C)(C)C1=CC(=C2[C@@H]3CC(=CC[C@H]3C(OC2=C1)(C)C)C(=O)O)O

Machine-readable entry (JSON)

LLM ingestion format: a structured superset of the entry (identifiers, binding, versioned legal status). Full corpus.