NEW YORK (360Dx) – The US interferon-gamma release assay (IGRA) tuberculosis testing market has been largely dominated by one player, but Quest Diagnostics' acquisition of the US operations of a smaller contender has potential to increase competition in the rapidly growing market, some experts say.
The leading IGRA tuberculosis test, Qiagen's QuantiFERON-TB had global sales of $185 million in 2017, about half of which was made up of US sales, according to a spokesman.
Quest's plans to acquire the US operations of Oxford Immunotec, maker of the competing T Spot.TB IGRA tuberculosis test, could add scale and efficiency to a less widely known competitor in a rapidly growing market, financial analysts and tuberculosis experts say. The $170 million deal, in which Quest will also acquire US operations of Oxford Immunotec's Accutix tick-borne disease test, is expected to close by year end.
"Right now Qiagen is the big player but Oxford Immunotec comes second, and the Quest acquisition is going to help them," said Claudia Denkinger, head of the tuberculosis program at the Foundation for Innovative New Diagnostics (FIND), a non-profit devoted to developing and delivering diagnostics for poverty-related diseases.
Oxford Immunotec, which does not break out TB testing volumes by region had total global sales of $103 million last year including both tuberculosis and tick-borne disease testing, according to the company's fourth quarter financial report. About 60 percent of the company's overall business was derived from US operations.
Quest, which also offers Qiagen's QuantiFERON, sees the acquisition as increasing choice for physicians, the company said. But increasing competition and choice in IGRA TB testing might be challenging, some experts warn.
"There are two [US Food and Drug Administration] approved IGRA TB tests. One is the QuantiFERON test that Qiagen sells and the other is the T-Spot test that Oxford Immunotec sells, but no one uses the T-Spot test," said Niaz Banaei, medical director of the Stanford Health Care Clinical Microbiology Laboratory and associate professor of pathology and medicine at Stanford University.
The US market for IGRA TB testing has been growing in the mid-teens to 20 percent according to investment bank Evercore ISI. Qiagen's QuantiFERON-TB has been a large driver of that growth. 2018 global sales are expected to grow approximately 20 percent from last year, and sales to Quest represent approximately 10 percent of that total, Qiagen spokesman Thomas Theuringer said in an email.
Quest for its part, stresses that it remains committed to QuantiFERON-TB, and a spokesperson noted that Quest plans to roll out QuantiFERON-TB Gold Plus, the fourth version of Quantiferon-TB later this month.
In a second and third quarter conference calls, Quest Chairman, President and CEO Steve Rusckowski specifically named QuantiFERON as an area where the company has seen strong growth.
In announcing the planned acquisition, he said that T-Spot.TB would "build on our momentum in tuberculosis services by enabling us to bring greater choice to physicians who seek innovative blood-based TB testing over traditional methods."
But growth of Oxford's T-Spot.TB has not been as steady. Oxford's US revenues grew 10 percent in the second quarter compared to the same quarter last year, Oxford President Peter Wrighton-Smith said during the firm's second quarter earnings call. The US revenue growth was driven by TB testing which returned to double-digit growth, the strongest growth in six quarters, he said. But in earlier quarters he cited headwinds due to less volume from immigration-related testing, an issue that had subsided by Q2, Wrighton-Smith said.
Stanford's Banaei believes it would not be simple for T-Spot.TB to replicate QuantiFERON-TB's momentum. While QuantiFERON-TB is a relatively automated test, Oxford's T-Spot.TB is not, he said.
"It's less automated because you have to separate the cells first, and then you have to manually count them, and then after counting them you have to inoculate a certain number of them per well. So that's why it's laborious because of the counting involved that is manual. It's a lot more work. It's not amenable to large volume testing," he said.
In July, Oxford announced a more automated version of the T-Spot.TB, called T-Cell Select, which has been CE-marked for use in Europe and some Asian countries. During the second quarter conference call, Wrighton-Smith declined to estimate a timeline for a US launch of the test.
Growing market despite stumbles
Blood-based IGRA TB testing has largely grown as a replacement for tuberculin skin tests. Both IGRA TB and tuberculin skin testing are used to test for latent tuberculosis, or tuberculosis without symptoms.
However, both Stanford's Banaei and FIND's Denkinger consider IGRA TB tests to be equal to tuberculin skin tests, but not more accurate.
"They are as good as the skin test. They are no better," Banaei said.
The rapid adoption of IGRA TB testing has been driven largely by logistics, according to Denkinger.
"You have to place the skin test and read it two days later. People have to come back for it and you lose people. That's why the IGRA is attractive," she said. "There is no data to show that either of the two is better or worse."
IGRA testing also got an added boost several years ago when there was a shortage of tuberculin, Denkinger noted.
In the US, IGRA testing has long received favorable guideline recommendations from the Centers for Disease Control and Prevention and medical groups, according to Banaei.
"If anything, when the first [CDC] guidelines came out about 10 years ago or so in the US, they endorsed IGRAs with little evidence really, which turned out to be problematic," Banaei said.
IGRA TB tests have a 5 percent to 10 percent false positive rate compared to tuberculin skin tests, which was eventually discovered largely due to repeat testing of healthcare workers who are required to be tested periodically, Banaei explained. After a period where there initially appeared to be a bump in tuberculosis among healthcare workers, studies later showed that some of the healthcare workers' positive IGRA TB test results were not always reproducible when healthcare workers returned for subsequent periodic testing.
"Initially those results were being accepted as real results because of the CDC recommendations. But then studies came out showing that there were false positive results, so today when someone gets a positive result, the first thing they will do is repeat it to see if its reproducible or not," he said.
Currently, the CDC recommends using an IGRA TB test rather than a tuberculin skin test for people over the age of 5 who may have received the Bacillus Calmette–Guérin vaccine against tuberculosis or who may not return to have their test read. In most other situations it views the two tests equally.
The Infectious Diseases Society of America recommendations are in agreement with the CDC regarding people who have received the BCG vaccine and/or may not return to have their test read, but it also conditionally recommends IGRA TB over tuberculin skin tests depending on clinical circumstances.
In February, CDC announced plans to mandate the use of IGRA tests in immigration TB screening, a move that could bode well for Qiagen and Oxford Immunotec.
Qiagen estimates that the US market for latent TB testing is only about 35 percent penetrated by IGRA testing.
In international TB testing, Denkinger sees other contenders potentially entering the market, including a new skin test from Statens Serum Institut using more specific antigens, the Diaskintest from Generium, and an ELISA-based test from SD Biosensor.
"I see [IGRA TB tests] growing, but I would say realistically in a five to 10 year time frame I see them beginning to be replaced by tests that have better positive predictive value," Denkinger said, referring to the SSI, Generium, and SD Biosensor tests.
In the US market, however, Banaei said, there doesn't appear to be any other competitors on the horizon. "There is a lot more work with active TB, but for latent TB this is pretty much what we have for the time being."