Medicines for Malaria Venture
Walter Reed Army Institute (Originator)
PATENT US 4617394
New Drug Application (NDA): 210795
FDA approved on July 20, 2018
This new drug application provides for the use of KRINTAFEL (tafenoquine) tablets for the radical cure (prevention of relapse) of Plasmodium vivax malaria in patients aged 16 years and older who are receiving appropriate antimalarial therapy for acute P. vivax infection….https://www.accessdata.fda.gov/drugsatfda_docs/appletter/2018/210795Orig1s000Ltr.pdf
Tafenoquine under the commercial name of Krintafel is an 8-aminoquinoline drug manufactured by GlaxoSmithKline that is being investigated as a potential treatment for malaria, as well as for malaria prevention.
The proposed indication for tafenoquine is for treatment of the hypnozoite stages of Plasmodium vivax and 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.
Like primaquine, tafenoquine causes hemolysis in people with G6PD deficiency. Indeed, the long half-life of tafenoquine suggests that particular care should be taken to ensure that individuals with severe G6PD 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.
In 2018 United States Food and Drug Administration (FDA) approved single dose tafenoquine for the radical cure (prevention of relapse) of Plasmodium vivax malaria.
Tafenoquine is used for the treatment and prevention of relapse of Vivax malaria in patients 16 years and older. Tafenoquine is not indicated to treat acute vivax malaria.
Malaria is a disease that remains to occur in many tropical countries. Vivax malaria, caused by Plasmodium vivax, is known to be less virulent and seldom causes death. However, it causes a substantive illness-related burden in endemic areas and it is known to present dormant forms in the hepatocytes named hypnozoites which can remain dormant for weeks or even months. This dormant form produces ongoing relapses
FDA Approves Tafenoquine, First New P VivaxMalaria Treatment in 60 Years
The US Food and Drug Administration (FDA) has approved, under Priority Review, GlaxoSmithKline (GSK)’s tafenoquine (Krintafel), which is the first single-dose medicine for the prevention of Plasmodium vivax (P vivax) malaria relapse in patients over the age of 16 years who are receiving antimalarial therapy. This is the first drug to be approved for the treatment of P vivax in over 60 years.
“[The] approval of Krintafel, the first new treatment for Plasmodium vivax malaria in over 60 years, is a significant milestone for people living with this type of relapsing malaria.” Hal Barron, MD, chief scientific officer and president of research and development of GSK, said in the announcement, “Together with our partner, Medicines for Malaria Venture (MMV), we believe Krintafel will be an important medicine for patients with malaria and contribute to the ongoing effort to eradicate this disease.”
Tafenoquine is an 8-aminoquinoline derivative with activity against all stages of the P vivax lifecycle, including hypnozoites. It was first synthesized by scientists at the Walter Reed Army Institute of Research in 1978, and in 2008, GSK entered into a collaboration with MMV, to develop tafenoquine as an anti-relapse medicine.
After an infected mosquito bite, the P vivax parasite infects the blood and causes an acute malaria episode and can also lie dormant in the liver (in a form known as hypnozoite) from where it periodically reactivates to cause relapses, which can occur weeks, months, or years after the onset of the initial infection. The dormant liver forms cannot be readily treated with most anti-malarial treatments. Primaquine, an 8-aminoquinolone, has been the only FDA-approved medicine that targeted the dormant liver stage to prevent relapse; however, effectiveness only occurs after 14 days and the treatment has shown to have poor compliance.
“The US FDA’s approval of Krintafel is a major milestone and a significant contribution towards global efforts to eradicate malaria,” commented David Reddy, PhD, chief executive officer of MMV in a recent statement, “The world has waited decades for a new medicine to counter P vivax malaria relapse. Today, we can say the wait is over. Moreover, as the first ever single-dose for this indication, Krintafel will help improve patient compliance.”
Approval for tafenoquine was granted based on the efficacy and safety data gleaned from a comprehensive global clinical development program for P vivaxprevention of relapse which has been designed by GSK and MMV in agreement with the FDA. The program consisted of 13 studies assessing the safety of a 300 mg single-dose of tafenoquine, including 3 double-blind studies referred to as DETECTIVE Parts 1 and 2 and GATHER.
With the approval of tafenoquine, GSK has also been awarded a tropical disease priority review voucher by the FDA. Additionally, GSK is waiting for a decision from Australian Therapeutics Good Administration regarding the regulatory submission for the drug.
P vivax malaria has caused around 8.5 million clinical infections each year, primarily in South Asia, South-East Asia, Latin America, and the Horn of Africa, a peninsula in East Africa. Symptoms include fever, chills, vomiting, malaise, headache and muscle pain, and can lead to death in severe cases.
Tafenoquine should not be administered to: patients who have glucose-6-phosphate dehydrogenase (G6PD) deficiency or have not been tested for G6PD deficiency, patients who are breastfeeding a child known to have G6PD deficiency or one that has not been tested for G6PD deficiency, or patients who are allergic to tafenoquine or any of the ingredients in tafenoquine or who have had an allergic reaction to similar medicines containing 8-aminoquinolines
Tafenoquine contains a stereocenter and consists of two enantiomers. This is a mixture of (R) – and the (S) – Form:
|Enantiomers of tafenoquine|
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.
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.
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.
An antimalarial drug, tafenoquine, as a fluorescent receptor for ratiometric detection of hypochlorite
Tafenoquine (TQ), a fluorescent antimalarial drug, was used as a receptor for the fluorometric detection of hypochlorite (OCl−). TQ itself exhibits a strong fluorescence at 476 nm, but OCl−-selective cyclization of its pentan-1,4-diamine moiety creates a blue-shifted fluorescence at 361 nm. This ratiometric response facilitates rapid, selective, and sensitive detection of OCl− in aqueous media with physiological pH. This response is also applicable to a simple test kit analysis and allows fluorometric OCl− imaging in living cells.
1 H NMR (300 MHz, CDCl3, TMS) d (ppm): 7.32 (q, 1H, J ¼ 18 Hz), 7.21 (d, 1H, J ¼ 6 Hz), 7.07 (s, 1H), 6.94 (d, 1H, J ¼ 6 Hz), 6.64 (s, 1H), 6.50 (s, 1H), 5.84 (d, 1H, J ¼ 6 Hz), 4.00 (s, 3H), 3.79 (s, 3H), 3.66 (s, 1H), 2.78 (d, 2H, J ¼ 6 Hz), 2.55 (s, 3H), 1.69 (dd, 6H, J ¼ 6 Hz, J ¼ 9 Hz), 1.35 (d, 3H, J ¼ 6 Hz).
13C NMR (100 MHz, CDCl3, TMS) d (ppm): 159.64, 148.961, 146.339, 142.010, 132.085, 131.760, 131.007, 129.968, 126.917, 125.344, 122.636, 120.681, 118.006, 115.256, 112.052, 94.996, 56.989, 52.870, 48.446, 42.248, 34.439, 30.130, 23.103, 20.833.
MS (m/z): M+ calcd for C24H28F3N3O3: 463.2083; found (ESI): 464.17 (M + H)+ .
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.
- Peters W (1999). “The evolution of tafenoquine–antimalarial for a new millennium?”. J R Soc Med. 92 (7): 345–352. PMC . PMID 10615272.
- 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.
- Nasveld 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.
- “Drugs@FDA: FDA Approved Drug Products”. www.accessdata.fda.gov. Retrieved 2018-07-23.
- 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
Methods and compositions for treating diseases associated with pathogenic proteins
Process for the preparation of quinoline derivatives
PROCESS FOR THE PREPARATION OF ANTI-MALARIAL DRUGS
MULTIDENTATE METAL COMPLEXES AND METHODS OF MAKING AND USING THEREOF
PROCESS FOR THE PREPARATION OF ANTI-MALARIAL DRUGS
MULTIDENTATE METAL COMPLEXES AND METHODS OF MAKING AND USING THEREOF
Use of interferon and a substance with an antimalarial activity for the treatment of malaria infections
4-methyl-5-(unsubstituted and substituted phenoxy)-2,6-dimethoxy-8-(aminoalkylamino) quinolines
|Synonyms||Etaquine, WR 238605, SB-252263|
|Chemical and physical data|
|Molar mass||463.493 g/mol|
|3D model (JSmol)|
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.”