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Single-dose tafenoquine therapy safely reduces the risk of Plasmodium vivax relapse in patients with normal glucose-6-phosphate dehydrogenase (G6PD) activity, according to the results of two phase 3, double-blind, randomized controlled trials.
Findings from both studies were published in two separate reports in the New England Journal of Medicine.
In the first study, the Dose and Efficacy Trial Evaluating Chloroquine and Tafenoquine in Vivax Elimination (DETECTIVE), the risk of P. vivax recurrence was approximately 70% lower with tafenoquine versus placebo, wrote Marcus V.G. Lacerda, MD, of Fundação de Medicina Tropical Doutor Heitor Vieira Dourado in Manaus, Brazil, and his colleagues.
The study included 522 patients with confirmed P. vivax infection from Peru, Brazil, Ethiopia, Cambodia, Thailand, and the Philippines. Patients received 3 days of chloroquine therapy (600 mg on days 1 and 2, and 300 mg on day 3) and were randomly assigned on a 2:1:1 basis to receive a single 300-mg dose of tafenoquine on day 1 or 2, primaquine once daily for 14 days, or placebo.
Since primaquine and tafenoquine can cause clinically significant hemolysis in individuals with G6PD deficiency, the study included only patients with normal G6PD activity.
In the intention-to-treat analysis, 62% of tafenoquine recipients were free from P. vivax recurrence (95% confidence interval [CI], 55%-69%) at 6 months, as were 70% of primaquine recipients (95% CI, 60%-77%) and 28% of placebo recipients (95% CI, 20%-37%). Compared with placebo, the reduction in risk of recurrence was 70% with tafenoquine (hazard ratio [HR], 0.30; 95% CI, 0.22-0.40; P less than .001) and 74% with primaquine.
Declines in hemoglobin levels were greatest in the tafenoquine group but were not associated with symptomatic anemia and resolved without intervention, the investigators wrote.
In addition to the quantitative G6PD test, the investigators also evaluated a qualitative test, which “failed to identify 16 patients most at risk for hemolysis,” they reported. “If tafenoquine use is expanded, adoption of reliable quantitative point-of-care G6PD tests will be needed; such tests are not currently available but are in development.”
In the second study, Global Assessment of Tafenoquine Hemolytic Risk (GATHER), Alejandro Llanos-Cuentas, MD, of Universidad Peruana Cayetano Heredia, Lima, Peru, and his colleagues enrolled 251 patients with confirmed P. vivax infection from Peru, Brazil, Columbia, Vietnam, and Thailand. They attempted to recruit women with moderate G6PD levels, but only one participant met this criterion – all others had normal G6PD activity.
Patients received 3-day course of chloroquine and were randomly assigned on a 2:1 basis to either tafenoquine or primaquine at the same doses as in the DETECTIVE trial.
At 6 months, 2% (95% CI, 1%-6%) of tafenoquine recipients and 1% (95% CI, 0.2%-6%) of primaquine recipients had decreased hemoglobin levels, but none consequently needed treatment. The medications also caused a similar degree and time course of hemoglobin decrease, the investigators noted.
A meta-analysis of GATHER and DETECTIVE confirmed that tafenoquine more often led to a decreased hemoglobin level (4% versus 1.5% with primaquine). Tafenoquine also did not meet prespecified criteria for noninferiority compared with primaquine, with respective 6-month recurrence rates of 67% versus 73%.
However, GATHER deployed “extensive” support to help patients adhere to the 15-day primaquine course, Dr. Llanos-Cuentas and his colleagues wrote. “Without such interventions, adherence to primaquine has been reported to be as low as 24% in Southeast Asia, with a corresponding attenuation of efficacy.”
GlaxoSmithKline and Medicines for Malaria Venture funded both studies, and GSK funded and conducted the meta-analysis. Dr. Llanos-Cuentas and several coinvestigators reported ties to GSK, Medicines for Malaria Venture, the Gambia, and LSTMH. Dr. Lacerda reported having no conflicts of interest.
SOURCES: Lacerda MVG et al. N Engl J Med 2019;380:215-28, and Llanos-Cuentas A et al. N Engl J Med 2019;380:229-41.
The studies show that tafenoquine reduces the risk of Plasmodium vivax recurrence in patients with quantitatively confirmed normal glucose-6-phosphate dehydrogenase (G6PD) activity, Nicholas J. White, FRS, wrote in an accompanying editorial.
But the need for this test and current prescribing restrictions will “limit the potential deployment of tafenoquine, at least in the immediate future,” he said. He praised the developers of tafenoquine “for persevering with this potentially valuable antimalarial drug, despite the difficulties,” but cautioned that it’s too soon to conclude that tafenoquine can be used safely and routinely on a large scale “and thus fulfill its promise as a radical improvement in the treatment of malaria.”
Currently, tafenoquine may not be used during pregnancy, lactation, or in patients younger than 16 years, Dr. White noted. Tafenoquine, like primaquine, causes dose-dependent hemolysis in patients with G6PD deficiency, but unlike primaquine, it is given as a single large dose. Hence, pretreatment quantitative G6PD testing is necessary. Point-of-care quantitative G6PD tests have been developed but await extensive field testing, Dr. White said.
Dr. White is with Mahidol University, Bangkok, Thailand, and University of Oxford, England. He reported having no financial disclosures. These comments are from his accompanying editorial ( N Engl J Med. 2019;380:285-6 ).
The studies show that tafenoquine reduces the risk of Plasmodium vivax recurrence in patients with quantitatively confirmed normal glucose-6-phosphate dehydrogenase (G6PD) activity, Nicholas J. White, FRS, wrote in an accompanying editorial.
But the need for this test and current prescribing restrictions will “limit the potential deployment of tafenoquine, at least in the immediate future,” he said. He praised the developers of tafenoquine “for persevering with this potentially valuable antimalarial drug, despite the difficulties,” but cautioned that it’s too soon to conclude that tafenoquine can be used safely and routinely on a large scale “and thus fulfill its promise as a radical improvement in the treatment of malaria.”
Currently, tafenoquine may not be used during pregnancy, lactation, or in patients younger than 16 years, Dr. White noted. Tafenoquine, like primaquine, causes dose-dependent hemolysis in patients with G6PD deficiency, but unlike primaquine, it is given as a single large dose. Hence, pretreatment quantitative G6PD testing is necessary. Point-of-care quantitative G6PD tests have been developed but await extensive field testing, Dr. White said.
Dr. White is with Mahidol University, Bangkok, Thailand, and University of Oxford, England. He reported having no financial disclosures. These comments are from his accompanying editorial ( N Engl J Med. 2019;380:285-6 ).
The studies show that tafenoquine reduces the risk of Plasmodium vivax recurrence in patients with quantitatively confirmed normal glucose-6-phosphate dehydrogenase (G6PD) activity, Nicholas J. White, FRS, wrote in an accompanying editorial.
But the need for this test and current prescribing restrictions will “limit the potential deployment of tafenoquine, at least in the immediate future,” he said. He praised the developers of tafenoquine “for persevering with this potentially valuable antimalarial drug, despite the difficulties,” but cautioned that it’s too soon to conclude that tafenoquine can be used safely and routinely on a large scale “and thus fulfill its promise as a radical improvement in the treatment of malaria.”
Currently, tafenoquine may not be used during pregnancy, lactation, or in patients younger than 16 years, Dr. White noted. Tafenoquine, like primaquine, causes dose-dependent hemolysis in patients with G6PD deficiency, but unlike primaquine, it is given as a single large dose. Hence, pretreatment quantitative G6PD testing is necessary. Point-of-care quantitative G6PD tests have been developed but await extensive field testing, Dr. White said.
Dr. White is with Mahidol University, Bangkok, Thailand, and University of Oxford, England. He reported having no financial disclosures. These comments are from his accompanying editorial ( N Engl J Med. 2019;380:285-6 ).
Single-dose tafenoquine therapy safely reduces the risk of Plasmodium vivax relapse in patients with normal glucose-6-phosphate dehydrogenase (G6PD) activity, according to the results of two phase 3, double-blind, randomized controlled trials.
Findings from both studies were published in two separate reports in the New England Journal of Medicine.
In the first study, the Dose and Efficacy Trial Evaluating Chloroquine and Tafenoquine in Vivax Elimination (DETECTIVE), the risk of P. vivax recurrence was approximately 70% lower with tafenoquine versus placebo, wrote Marcus V.G. Lacerda, MD, of Fundação de Medicina Tropical Doutor Heitor Vieira Dourado in Manaus, Brazil, and his colleagues.
The study included 522 patients with confirmed P. vivax infection from Peru, Brazil, Ethiopia, Cambodia, Thailand, and the Philippines. Patients received 3 days of chloroquine therapy (600 mg on days 1 and 2, and 300 mg on day 3) and were randomly assigned on a 2:1:1 basis to receive a single 300-mg dose of tafenoquine on day 1 or 2, primaquine once daily for 14 days, or placebo.
Since primaquine and tafenoquine can cause clinically significant hemolysis in individuals with G6PD deficiency, the study included only patients with normal G6PD activity.
In the intention-to-treat analysis, 62% of tafenoquine recipients were free from P. vivax recurrence (95% confidence interval [CI], 55%-69%) at 6 months, as were 70% of primaquine recipients (95% CI, 60%-77%) and 28% of placebo recipients (95% CI, 20%-37%). Compared with placebo, the reduction in risk of recurrence was 70% with tafenoquine (hazard ratio [HR], 0.30; 95% CI, 0.22-0.40; P less than .001) and 74% with primaquine.
Declines in hemoglobin levels were greatest in the tafenoquine group but were not associated with symptomatic anemia and resolved without intervention, the investigators wrote.
In addition to the quantitative G6PD test, the investigators also evaluated a qualitative test, which “failed to identify 16 patients most at risk for hemolysis,” they reported. “If tafenoquine use is expanded, adoption of reliable quantitative point-of-care G6PD tests will be needed; such tests are not currently available but are in development.”
In the second study, Global Assessment of Tafenoquine Hemolytic Risk (GATHER), Alejandro Llanos-Cuentas, MD, of Universidad Peruana Cayetano Heredia, Lima, Peru, and his colleagues enrolled 251 patients with confirmed P. vivax infection from Peru, Brazil, Columbia, Vietnam, and Thailand. They attempted to recruit women with moderate G6PD levels, but only one participant met this criterion – all others had normal G6PD activity.
Patients received 3-day course of chloroquine and were randomly assigned on a 2:1 basis to either tafenoquine or primaquine at the same doses as in the DETECTIVE trial.
At 6 months, 2% (95% CI, 1%-6%) of tafenoquine recipients and 1% (95% CI, 0.2%-6%) of primaquine recipients had decreased hemoglobin levels, but none consequently needed treatment. The medications also caused a similar degree and time course of hemoglobin decrease, the investigators noted.
A meta-analysis of GATHER and DETECTIVE confirmed that tafenoquine more often led to a decreased hemoglobin level (4% versus 1.5% with primaquine). Tafenoquine also did not meet prespecified criteria for noninferiority compared with primaquine, with respective 6-month recurrence rates of 67% versus 73%.
However, GATHER deployed “extensive” support to help patients adhere to the 15-day primaquine course, Dr. Llanos-Cuentas and his colleagues wrote. “Without such interventions, adherence to primaquine has been reported to be as low as 24% in Southeast Asia, with a corresponding attenuation of efficacy.”
GlaxoSmithKline and Medicines for Malaria Venture funded both studies, and GSK funded and conducted the meta-analysis. Dr. Llanos-Cuentas and several coinvestigators reported ties to GSK, Medicines for Malaria Venture, the Gambia, and LSTMH. Dr. Lacerda reported having no conflicts of interest.
SOURCES: Lacerda MVG et al. N Engl J Med 2019;380:215-28, and Llanos-Cuentas A et al. N Engl J Med 2019;380:229-41.
Single-dose tafenoquine therapy safely reduces the risk of Plasmodium vivax relapse in patients with normal glucose-6-phosphate dehydrogenase (G6PD) activity, according to the results of two phase 3, double-blind, randomized controlled trials.
Findings from both studies were published in two separate reports in the New England Journal of Medicine.
In the first study, the Dose and Efficacy Trial Evaluating Chloroquine and Tafenoquine in Vivax Elimination (DETECTIVE), the risk of P. vivax recurrence was approximately 70% lower with tafenoquine versus placebo, wrote Marcus V.G. Lacerda, MD, of Fundação de Medicina Tropical Doutor Heitor Vieira Dourado in Manaus, Brazil, and his colleagues.
The study included 522 patients with confirmed P. vivax infection from Peru, Brazil, Ethiopia, Cambodia, Thailand, and the Philippines. Patients received 3 days of chloroquine therapy (600 mg on days 1 and 2, and 300 mg on day 3) and were randomly assigned on a 2:1:1 basis to receive a single 300-mg dose of tafenoquine on day 1 or 2, primaquine once daily for 14 days, or placebo.
Since primaquine and tafenoquine can cause clinically significant hemolysis in individuals with G6PD deficiency, the study included only patients with normal G6PD activity.
In the intention-to-treat analysis, 62% of tafenoquine recipients were free from P. vivax recurrence (95% confidence interval [CI], 55%-69%) at 6 months, as were 70% of primaquine recipients (95% CI, 60%-77%) and 28% of placebo recipients (95% CI, 20%-37%). Compared with placebo, the reduction in risk of recurrence was 70% with tafenoquine (hazard ratio [HR], 0.30; 95% CI, 0.22-0.40; P less than .001) and 74% with primaquine.
Declines in hemoglobin levels were greatest in the tafenoquine group but were not associated with symptomatic anemia and resolved without intervention, the investigators wrote.
In addition to the quantitative G6PD test, the investigators also evaluated a qualitative test, which “failed to identify 16 patients most at risk for hemolysis,” they reported. “If tafenoquine use is expanded, adoption of reliable quantitative point-of-care G6PD tests will be needed; such tests are not currently available but are in development.”
In the second study, Global Assessment of Tafenoquine Hemolytic Risk (GATHER), Alejandro Llanos-Cuentas, MD, of Universidad Peruana Cayetano Heredia, Lima, Peru, and his colleagues enrolled 251 patients with confirmed P. vivax infection from Peru, Brazil, Columbia, Vietnam, and Thailand. They attempted to recruit women with moderate G6PD levels, but only one participant met this criterion – all others had normal G6PD activity.
Patients received 3-day course of chloroquine and were randomly assigned on a 2:1 basis to either tafenoquine or primaquine at the same doses as in the DETECTIVE trial.
At 6 months, 2% (95% CI, 1%-6%) of tafenoquine recipients and 1% (95% CI, 0.2%-6%) of primaquine recipients had decreased hemoglobin levels, but none consequently needed treatment. The medications also caused a similar degree and time course of hemoglobin decrease, the investigators noted.
A meta-analysis of GATHER and DETECTIVE confirmed that tafenoquine more often led to a decreased hemoglobin level (4% versus 1.5% with primaquine). Tafenoquine also did not meet prespecified criteria for noninferiority compared with primaquine, with respective 6-month recurrence rates of 67% versus 73%.
However, GATHER deployed “extensive” support to help patients adhere to the 15-day primaquine course, Dr. Llanos-Cuentas and his colleagues wrote. “Without such interventions, adherence to primaquine has been reported to be as low as 24% in Southeast Asia, with a corresponding attenuation of efficacy.”
GlaxoSmithKline and Medicines for Malaria Venture funded both studies, and GSK funded and conducted the meta-analysis. Dr. Llanos-Cuentas and several coinvestigators reported ties to GSK, Medicines for Malaria Venture, the Gambia, and LSTMH. Dr. Lacerda reported having no conflicts of interest.
SOURCES: Lacerda MVG et al. N Engl J Med 2019;380:215-28, and Llanos-Cuentas A et al. N Engl J Med 2019;380:229-41.
FROM NEW ENGLAND JOURNAL OF MEDICINE
Key clinical point:
Major finding: In DETECTIVE, 6-month rates of freedom from recurrence from Plasmodium vivax infection were 62% with tafenoquine, 70% with primaquine, and 28% with placebo.
Study details: Two randomized, phase 3, double-blind controlled trials of patients with confirmed P. vivax infection (DETECTIVE and GATHER) and without deficient G6PD activity.
Disclosures: GlaxoSmithKline and Medicines for Malaria Venture funded both studies, and GSK funded and conducted the meta-analysis. Dr. Llanos-Cuentas and several coinvestigators reported ties to GSK, Medicines for Malaria Venture, the Gambia, and LSTMH. Dr. Lacerda reported having financial disclosures.
Source: Lacerda MVG et al. N Engl J Med 2019;380:215-28, and Llanos-Cuentas A et al. N Engl J Med 2019;380:229-41.