DRUG APPROVALS BY DR ANTHONY MELVIN CRASTO
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Tafenoquine
N-[2,6-dimethoxy-4-methyl-5-[3-(trifluoromethyl)phenoxy]quinolin-8-yl]pentane-1,4-diamine
Medicines for Malaria Venture
Walter Reed Army Institute (Originator)
April 28, 2014
GlaxoSmithKline (GSK) and Medicines for Malaria Venture (MMV) announced the start of a Phase 3 global program to evaluate the efficacy and safety of tafenoquine, an investigational medicine which is being developed for the treatment and relapse prevention (radical cure) of Plasmodium vivax (P. vivax) malaria.
P. vivax malaria, a form of the disease caused by one of several species of Plasmodium parasites known to infect humans, occurs primarily in South and South East Asia, Latin America and the horn of Africa. Severe anemia, malnutrition and respiratory distress are among the most serious consequences described to be caused by the infection.
The Phase 3 program includes two randomized, double-blind treatment studies to investigate tafenoquine in adult patients with P. vivax malaria. The DETECTIVE study (TAF112582) aims to evaluate the efficacy, safety and tolerability of tafenoquine as a radical cure for P. vivax malaria, co-administered with chloroquine, a blood stage anti-malarial treatment. The GATHER study (TAF116564) aims to assess the incidence of hemolysis and safety and efficacy of tafenoquine compared to primaquine, the only approved treatment currently available for the radical cure of P. vivax malaria.
Tafenoquine is not yet approved or licensed for use anywhere in the world.
“P. vivax malaria can affect people of all ages and is particularly insidious because it has the potential to remain dormant within the body in excess of a year, and causes some patients to experience repeated episodes of illness after the first mosquito bite,” said Nicholas Cammack, head, Tres Cantos Medicines Development Center for Diseases of the Developing World. “Our investigation of tafenoquine for the treatment of P. vivax malaria is part of GSK’s efforts to tackle the global burden of malaria. Working with our partners, including MMV, we are determined to stop malaria in all its forms.”
“One of the big challenges we face in tackling malaria is to have new medicines to prevent relapse, caused by dormant forms of P. vivax,” said Dr. Timothy Wells, MMV’s chief scientific officer. “The Phase 3 program is designed to build upon the promising results of the Phase 2b study which showed that treatment with tafenoquine prevented relapses. If successful, tafenoquine has the potential to become a major contributor to malaria elimination. It’s a great privilege to be working with GSK on this project; they have a clear commitment to changing the face of public health in the countries in which we are working.”
Tafenoquine succinate, Etaquine, SB-252263, WR-238605
in phase 2
Medicines for Malaria Venture
Walter Reed Army Institute (Originator)
Tafenoquine is an 8-aminoquinoline drug manufactured by GlaxoSmithKline that is being investigated as a potential treatment for malaria, as well as for malaria prevention.[1][2]
The proposed indication for tafenoquine is for treatment of the hypnozoite stages of Plasmodium vivax (and also Plasmodium ovale) that are responsible for relapse of these malaria species even when the blood stages are successfully cleared. This is only now achieved by administration of daily primaquine for 14 days. The main advantage of tafenoquine is that it has a long half-life (2–3 weeks) and therefore a single treatment may be sufficient to clear hypnozoites. The shorter regimen has been described as an advantage.[3]
Like primaquine, tafenoquine causes haemolysis in people with G-6-P deficiency.[1] Indeed the long half-life of tafenoquine suggests that particular care should be taken to ensure that individuals with severe deficiency do not receive the drug.
The dose of tafenoquine has not been firmly established, but for the treatment of Plasmodium vivax malaria, a dose of 800 mg over three days has been used.[4]
Synonyms
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US 4431807
Nitration of 1,2-dimethoxybenzene (XXIX) with HNO3/AcOH gives 4,5-dimethoxy-1,2-dinitrobenzene (XXX), which is treated with ammonia in hot methanol to yield 4,5-dimethoxy-2-nitroaniline (XXXI). Cyclization of compound (XXXI) with buten-2-one (XXXII) by means of H3PO4 and H3AsO4 affords 5,6-dimethoxy-4-methyl-8-nitroquinoline (XXXIII), which is selectively mono-demethylated by means of HCl in ethanol to provide 5-hydroxy-6-methoxy-4-methyl-8-nitroquinoline (XXXIV). Reaction of quinoline (XXXIV) with POCl3 gives the corresponding 5-chloro derivative (XXXV), which is condensed with 3-(trifluoromethyl)phenol (IV) by means of KOH to yield the diaryl ether (XXXVI). Finally, the nitro group of (XXXVI) is reduced by means of H2 over PtO2 in THF or H2 over Raney nickel.
Nitration of 2-fluoroanisole (XXXVII) with HNO3/Ac2O gives 3-fluoro-4-methoxynitrobenzene (XXXVIII), which is reduced to the corresponding aniline (XXXIX) with SnCl2/HCl. Reaction of compound (XXXIX) with Ac2O yields the acetanilide (XL), which is nitrated with HNO3 to afford 5-fluoro-4-methoxy-2-nitroacetanilide (XLI). Hydrolysis of (XLI) with NaOH provides 5-fluoro-4-methoxy-2-nitroaniline (XLII), which is cyclized with buten-2-one (XXXII) by means of As2O5 and H3PO4 to furnish 5-fluoro-6-methoxy-4-methyl-8-nitroquinoline (XLIII). Condensation of quinoline (XLIII) with 3-(trifluoromethyl)phenol (IV) by means of K2CO3 gives the diaryl ether (XXXIV), which is finally reduced by means of H2 over PtO2 in THF.
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US 4617394
Reaction of 8-amino-6-methoxy-4-methyl-5-[3-(trifluoromethyl)phenoxy]quinoline (XIV) with phthalic anhydride (XV) affords the phthalimido derivative (XVI), which is oxidized with MCPBA to yield the quinoline N-oxide (XVII). Treatment of compound (XVII) with neutral alumina gives the quinolone derivative (XVIII), which by reaction with POCl3 in refluxing CHCl3 provides the 2-chloroquinoline derivative (XIX). Alternatively, reaction of the quinoline N-oxide (XVII) with POCl3 as before also gives the 2-chloroquinoline derivative (XIX) The removal of the phthalimido group of compound (XIX) by means of hydrazine in refluxing ethanol gives the chlorinated aminoquinoline (XX), which is finally treated with MeONa in hot DMF.
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US 6479660; WO 9713753
Chlorination of 6-methoxy-4-methylquinolin-2(1H)-one (I) with SO2Cl2 in hot acetic acid gives the 5-chloro derivative (II), which is nitrated with HNO3 in H2SO4 to yield the 8-nitroquinolinone (III). Condensation of compound (III) with 3-(trifluoromethyl)phenol (IV) by means of KOH in NMP provides the diaryl ether (V), which is treated with refluxing POCl3 to afford the 2-chloroquinoline (VI). Reaction of compound (VI) with MeONa in refluxing methanol results in the 2,6-dimethoxyquinoline derivative (VII), which is reduced with hydrazine over Pd/C to give the 8-aminoquinoline derivative (VIII). Condensation of aminoquinoline (VIII) with N-(4-iodopentyl)phthalimide (IX) by means of diisopropylamine in hot NMP yields the phthalimido precursor (X), which is finally cleaved with hydrazine in refluxing ethanol.
Reaction of 1,4-dibromopentane (XI) with potassium phthalimide (XII) gives N-(4-bromopentyl)phthalimide (XIII), which is then treated with NaI in refluxing acetone.
Reaction of 4-methoxyaniline (XXI) with ethyl acetoacetate (XXII) by means of triethanolamine in refluxing xylene gives the acetoacetanilide (XXIII), which is cyclized by means of hot triethanolamine and H2SO4 to yield 6-methoxy-4-methylquinolin-2(1H)-one (I), which is treated with refluxing POCl3 to provide 2-chloro-6-methoxy-4-methylquinoline (XXIV). Reaction of compound (XXIV) with SO2Cl2 in hot AcOH affords 2,5-dichloro-6-methoxy-4-methylquinoline (XXV), which is treated with MeONa in refluxing methanol to furnish 5-chloro-2,6-dimethoxy-4-methylquinoline (XXVI). Alternatively, the reaction of compound (XXIV) with MeONa as before gives 2,6-dimethoxy-4-methylquinoline (XXVII), which is treated with SO2Cl2 in hot AcOH to give the already described 5-chloro-2,6-dimethoxy-4-methylquinoline (XXVI). Nitration of compound (XXVI) with KNO3 and P2O5 gives the 8-nitroquinoline derivative (XXVIII), which is condensed with 3-(trifluoromethyl)phenol (IV) by means of KOH in hot NMP to yield the diaryl ether (VII). Finally, the nitro group of compound (VII) is reduced with hydrazine over Pd/C.
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J Med Chem 1989,32(8),1728-32
Synthesis of the intermediate diazepinone (IV) is accomplished by a one-pot synthesis. Condensation of 2-chloro-3-aminopyridine (I) with the anthranilic ester (II) is effected in the presence of potassium tert-butoxide as a catalyst. The resulting anthranilic amide (III) is cyclized under the influence of catalytic amounts of sulfuric acid. Treatment of (IV) with chloroacetylchloride in toluene yields the corresponding choroacetamide (V). The side chain of AQ-RA 741 is prepared starting from 4-picoline, which is alkylated by reaction with 3-(diethylamino)propylchloride in the presence of n-butyllithium. Hydrogenation of (VIII) using platinum dioxide as a catalyst furnishes the diamine (IX), which is coupled with (V) in the presence of catalytic amounts of sodium iodide in acetone leading to AQ-RA 741 as its free base.
- Shanks GD, Oloo AJ, Aleman GM et al. (2001). “A New Primaquine Analogue, Tafenoquine (WR 238605), for prophylaxis against Plasmodium falciparum malaria”. Clin Infect Dis 33 (12): 1968–74. doi:10.1086/324081. JSTOR 4482936.PMID 11700577.
- Lell B, Faucher JF, Missinou MA et al. (2000). “Malaria chemoprophylaxis with tafenoquine: a randomised study”.Lancet 355 (9220): 2041–5. doi:10.1016/S0140-6736(00)02352-7. PMID 10885356.
- Elmes NJ, Nasveld PE, Kitchener SJ, Kocisko DA, Edstein MD (November 2008). “The efficacy and tolerability of three different regimens of tafenoquine versus primaquine for post-exposure prophylaxis of Plasmodium vivax malaria in the Southwest Pacific”. Transactions of the Royal Society of Tropical Medicine and Hygiene 102 (11): 1095–101.doi:10.1016/j.trstmh.2008.04.024. PMID 18541280.
- Nasvelda P, Kitchener S. (2005). “Treatment of acute vivax malaria with tafenoquine”. Trans R Soc Trop Med Hyg 99 (1): 2–5. doi:10.1016/j.trstmh.2004.01.013. PMID 15550254.
- Peters W (1999). “The evolution of tafenoquine–antimalarial for a new millennium?”. J R Soc Med 92 (7): 345–352.PMID 10615272.
- J Med Chem 1982,25(9),1094
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8-3-2007
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Methods and compositions for treating diseases associated with pathogenic proteins
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12-6-2006
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Process for the preparation of quinoline derivatives
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3-14-2002
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PROCESS FOR THE PREPARATION OF ANTI-MALARIAL DRUGS
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4-2-1998
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MULTIDENTATE METAL COMPLEXES AND METHODS OF MAKING AND USING THEREOF
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4-18-1997
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PROCESS FOR THE PREPARATION OF ANTI-MALARIAL DRUGS
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12-20-1996
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MULTIDENTATE METAL COMPLEXES AND METHODS OF MAKING AND USING THEREOF
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12-15-1993
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Use of interferon and a substance with an antimalarial activity for the treatment of malaria infections
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10-15-1986
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4-methyl-5-(unsubstituted and substituted phenoxy)-2,6-dimethoxy-8-(aminoalkylamino) quinolines
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New Drug Approvals 