Clinical data
Other namesPNU-95,666
ATC code
  • none
  • (R)-5,6-Dihydro-5-(methylamino)-4H-imidazo[4,5,1-ij]quinolin-2(1H)-one
CAS Number
PubChem CID
Chemical and physical data
Molar mass203.245 g·mol−1
3D model (JSmol)
  • CN[C@@H]1Cc2cccc3[nH]c(=O)n(C1)c23

Sumanirole (PNU-95,666) is a highly selective D2 receptor full agonist, the first of its kind to be discovered.[1][2][3] It was developed for the treatment of Parkinson's disease and restless leg syndrome. While it has never been approved for medical use [4][5] it is a highly valuable tool compound for basic research to identify neurobiological mechanisms that are based on a dopamine D2-linked (vs. D1-, D3-, D4-, and D5-linked) mechanism of action.[3]

In 2004, Pfizer announced the end of their clinical development program for sumanirole, citing “recent studies that failed to sufficiently distinguish sumanirole from currently available therapies”.[6]

See also


  1. ^ Romero AG, et al. Synthesis of the selective D2 receptor agonist PNU-95666E from D-phenylalanine using a sequential oxidative cyclization strategy. Journal of Organic Chemistry. 1997; 62(19):6582.
  2. ^ McCall RB, Lookingland KJ, Bédard PJ, Huff RM (September 2005). "Sumanirole, a highly dopamine D2-selective receptor agonist: in vitro and in vivo pharmacological characterization and efficacy in animal models of Parkinson's disease". The Journal of Pharmacology and Experimental Therapeutics. 314 (3): 1248–56. doi:10.1124/jpet.105.084202. PMID 15980060. S2CID 9835081.
  3. ^ a b Weber M, Chang WL, Breier MR, Yang A, Millan MJ, Swerdlow NR (March 2010). "The effects of the dopamine D2 agonist sumanirole on prepulse inhibition in rats". European Neuropsychopharmacology. 20 (6): 421–425. doi:10.1016/j.euroneuro.2010.02.011. PMC 2864324. PMID 20346635.
  4. ^ Barone P, Lamb J, Ellis A, Clarke Z (March 2007). "Sumanirole versus placebo or ropinirole for the adjunctive treatment of patients with advanced Parkinson's disease". Movement Disorders. 22 (4): 483–9. doi:10.1002/mds.21191. PMID 17115380. S2CID 20961008.
  5. ^ Garcia-Borreguero D, Winkelman J, Adams A, Ellis A, Morris M, Lamb J, Layton G, Versavel M (March 2007). "Efficacy and tolerability of sumanirole in restless legs syndrome: a phase II, randomized, double-blind, placebo-controlled, dose-response study". Sleep Medicine. 8 (2): 119–27. doi:10.1016/j.sleep.2006.05.018. PMID 17239657.
  6. ^ Pfizer, Inc. "Pfizer to Discontinue Sumanirole Development Program". Parkinson's Disease Foundation.