CDCtravel

Clinical Update: Tafenoquine Approved for Malaria Prophylaxis and Treatment

The US Food and Drug Administration (FDA) has approved the drug tafenoquine for 2 indications:

1. Prophylaxis of malaria
2. Radical cure of Plasmodium vivax malaria

Tafenoquine is an 8-aminoquinoline antimalarial drug related to primaquine. As with primaquine, tafenoquine can cause severe hemolytic anemia in people with G6PD deficiency. Those with partial deficiency that may be missed by qualitative testing may also be at risk for hemolysis. Therefore, physicians must perform quantitative G6PD testing before prescribing tafenoquine. Tafenoquine use in people with G6PD deficiency or unknown G6PD status is contraindicated.

The long terminal half-life of tafenoquine (approximately 16 days) offers potential advantages in less frequent dosing for prophylaxis and a single-dose course for treatment.
Tafenoquine approved for malaria prophylaxis and treatment

Rapid tests for diagnosing malaria caused by Plasmodium vivax in people living in areas where malaria is very common

What is the aim of the review?
Malaria infection is caused mainly by two species of malaria parasite: Plasmodium falciparum and Plasmodium vivax. The aim of this review was to evaluate rapid diagnostic tests (RDTs) to diagnose P vivax infection.

Why are rapid tests for P vivax malaria important?
For clinical management, knowing which parasite species is causing the malaria is important as the drug treatments differ. For P vivax infection, an additional drug is required to eliminate the infection from the liver. For public health control of malaria, we know that P falciparum is declining over the previous 15 years, and infections from P vivax have therefore increased in importance.

What was studied in this review?
RDTs provide results quickly and are often as a dipstick. We studied RDTs that specifically test for P vivax malaria. RDTs are simple to use, point‐of‐care tests. They are suitable for use in rural settings by primary healthcare workers, using drop of blood on the dipstick that causes colour change and a distinct line that indicates a positive test result. Healthcare workers in rural areas can perform RDTs for P vivax without needing a laboratory or special equipment. We wanted to find out which brands of RDTs were the most accurate for diagnosing P vivax malaria. We compared the new tests against the standard form of diagnosis with microscopy, and also more recent methods polymerase chain reaction (PCR): a molecular method to identify P vivax DNA in blood samples.

What are the main results of the review?
We included 10 studies that looked at the accuracy of six diagnostic test brands for detecting P vivax malaria in people with suspected malaria symptoms. The studies were conducted in Ethiopia (four studies), India (two studies) and Bangladesh, Brazil, Colombia, and Sudan (one study each).

Compared with microscopy, the Care Start Malaria Pf/Pv Combo test performed well with 99% sensitivity and specificity (four studies). This means that:

• for every 100 people tested who have P vivax malaria, one person will have a negative test result, and might not receive the right treatment soon enough;
• for every 100 people tested who do not have P vivax malaria, one will have a positive result, and might receive unnecessary treatment.

Compared with microscopy, the Falcivax Device Rapid test had a sensitivity of 77% and a specificity of 99% (two studies). This means that:

• For every 100 people tested who have P vivax malaria, 23 people will have a negative test result; and,
• for every 100 people tested who do not have P vivax malaria, one person will have a positive result.

We are moderately confident (certain) in the accuracy results for the Care Start Malaria Pf/Pv Combo test. The results are from a small number of studies (four), so our findings may change when results from further studies become available. We are less confident in the accuracy results for the Falcivax Device Rapid test, because these came from only two studies. Our findings for this test will probably change when results from further studies become available. Our results are based on a small number of studies, so we could not reliably assess all six brands of antibody test or compare their accuracy. Most studies included in this review had limitations: it was not clear how people were selected for testing, or how the study results were assessed and checked, which could have affected the results. Some rapid antibody tests were investigated by only one study. Some studies did not report clearly how common P malaria was in the area where the study was done.

How up‐to‐date is this review?
The review authors searched for studies published up to 30 July 2019.

FDA Approval: ACTEMRA® for Giant Cell Arteritis

The US Food and Drug Administration (FDA) approved in May the first drug to treat adults with giant cell arteritis.
It is ACTEMRA® (tocilizumab), an injectable solution for subcutaneous administration, already used in the treatment of rheumatoid arthritis. With the expansion of its use, the drug becomes the first FDA-approved therapy specifically for this type of vasculitis.
The efficacy and safety of ACTEMRA® were established in a double-blind, placebo-controlled study of 251 patients with giant cell arteritis. The primary efficacy endpoint was the proportion of patients achieving sustained remission from week 12 to week 52.
Sustained remission was defined as absence of symptoms, normalization of inflammatory laboratory tests and reduction of the use of prednisone.
A higher proportion of patients receiving ACTEMRA® subcutaneously with standardized prednisone regimens achieved sustained remission compared to patients receiving placebo. The cumulative dose of prednisone was lower in subjects treated with the drug.

Source: Food and Drug Administration.

Malaria Outbreak in Wenceslau Guimarães, Bahia State, Brazil

A malaria outbreak has been reported in the town of Wenceslau Guimarães in Bahia State, Brazil. Antimalarial medication is now recommended for travelers to this area.
CDC has received reports of an outbreak of P. vivax malaria in Wenceslau Guimarães. Bahia State is not a malaria-endemic area. However, in the town of Wenceslau Guimarães there were 21 locally transmitted cases reported January 16–22. The Brazilian Ministry of Health and the public health authorities in Bahia State are continuing to monitor and respond to this outbreak.
As Bahia State is not a malaria-endemic area, CDC has previously not recommended malaria prophylaxis. However, with this focal outbreak, CDC now recommends that travelers to the town of Wenceslau Guimarães in Bahia State take antimalarials to prevent malaria. Effective antimalarial options for P. vivax include atovaquone-proguanil, chloroquine, doxycycline, mefloquine, and in those without glucose-6-phosphate dehydrogenase deficiency, primaquine. CDC will continue to monitor the malaria situation in Bahia State and will update these recommendations as needed.