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FDA Approves Oxford Immunotec Babesia Assays for Blood Screening

NEW YORK (360Dx) – The US Food and Drug Administration on Tuesday approved Oxford Immunotec's Imugen arrayed fluorescent immunoassay for the detection of antibodies to Babesia microti in human plasma samples, and the Imugen nucleic acid test for the detection of B. microti DNA in human whole blood samples.

The FDA noted that the approved assays are in-house tests that can only be performed at Oxford Immunotec's facility in Norwood, Massachusetts, and that the tests are not intended for use in the diagnosis of babesiosis infections.

The assays are intended to be used as donor screening tests on samples from individual human donors, including volunteer donors of whole blood and blood components, and from living-organ and tissue donors, the FDA said.

“While babesiosis is both preventable and treatable, until [Tuesday] there was no way to screen for infections amongst blood donors,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said in a statement. “[Tuesday's FDA] actions represent the first approvals of babesia detection tests for use in screening donors of whole blood and blood components, and other living donors.”

FDA guidance for the testing of donor samples for Babesia currently does not exist, but the agency said that it is planning later this year to issue draft guidance with recommendations for reducing the risk of transfusion-transmitted babesiosis.

The approval came a week after Oxford Immunotec noted on a conference call to discuss its fourth quarter earnings that it expects to shut down a project to develop babesia blood-donor screening assays because of an FDA letter that required additional clinical testing prior to approval. In June 2016, the firm had acquired substantially all the assets of tick-borne disease testing company Imugen in a transaction worth $22.2 million in cash

In a research note, Cowen analyst Doug Schenkel said that the approvals were "expected and are separate from the Babesia screening assay that received a complete response letter in mid-February." Accordingly, he said, Oxford's management still expects to exit this business, depending on conversations with customers and the FDA.

However, Piper Jaffray analyst William Quirk said in a research note that Oxford Immunotec performs about 1 million tests for babesia in US areas at risk for deer ticks. With FDA approval, the company can "negotiate the transition to commercial pricing" of its assays from more restrictive investigational new drug application pricing, he said. The commercial price could be close to between $6 and $16 per test, which suggests an incremental $3 million to $12 million in high-margin revenue for the firm at the current run rate, he noted. Competition still exists for Oxford from Grifols and Roche, which are both working on babesia assays, but "should screening increase to cover all at-risk areas," this type of testing could represent a $60 million to $150 million market for Oxford, Quirk added.

The investigational use of blood donor testing for babesia has been in place since August 2012 in selected endemic areas under investigational new drug applications (INDs). The FDA noted that the data collected from investigational testing and from additional studies prevented the release of "hundreds of potentially infectious donations," and demonstrated that the tests are effective in screening donors for B. microti infection.

Babesiosis is caused by Babesia parasites that are transmitted by Ixodes scapularis ticks, also known as blacklegged or deer ticks, and B. microti is the main species that causes infection in the US. Up to 2,000 cases of babesiosis are reported in the US each year, and the majority are reported from states in the Northeast and upper Midwest, according to the FDA. Babesia can also be transmitted by transfusion of blood or blood components collected from an infected donor.

The vast majority of people infected with B. microti do not have symptoms and are never diagnosed, the FDA said. Some people develop flu-like symptoms, such as fever, headache, and body aches. The FDA noted that the US Centers for Disease Control and Prevention warns that for certain people, especially those with a weak immune system, the infection can be a severe, life-threatening disease, and that while bloodborne transmission of babesiosis is thought to be uncommon, it is the most frequently reported transfusion-transmitted parasitic infection in the US and remains an important concern.