HONG KONG – Celltrion Inc. continues its quest to take its Diatrust COVID-19 Ag Rapid Test overseas, after receiving the FDA’s emergency use authorization (EUA).

The Incheon, South Korea-based company also submitted results of clinical trials in which 450 people throughout the U.S. were tested between February and March 2021 to the regulator, with the trial results currently under review.

The U.S. authorization follows the European EC certification that the company already received for the test kit in November 2020.

“With the FDA approval in hand, Celltrion can now make good on our ₩240 billion (US$214.73 million) contract that Celltrion USA Inc. signed with New York-based Prime Healthcare Distributors in December 2020, and we will begin supplying Diatrust COVID-19 Ag Rapid Test to the U.S. immediately,” a Celltrion spokesperson told BioWorld.

The approval also covers serial testing, where patients can be tested twice over two or three days with at least 24 hours and no more than 48 hours between test, allowing for two tests to be run per week. Serial testing also means asymptomatic patients can be observed, and patients can be isolated, at an early stage.

More than 8.3 million COVID-19 tests have been performed and concluded in South Korea as of April 20, according to the country’s Ministry of Health and Welfare data.

The emergence of mutated strains of the SARS-CoV-2 virus that are potentially more infectious, has increased the importance of developing treatments and vaccines that are able to treat these strains as well. It has also highlighted the need for test kits that can identify the virus strain to prevent their spread.

Keeping this in mind, the Diatrust COVID-19 Ag Rapid Test can identify variant SARS-CoV-2 strains identified in the U.K., South Africa, Brazil, California and New York, with the ability verified by in-vitro tests. Celltrion was in the middle of clinical trials as the B.1.1.7 variant, first discovered in the U.K. in September 2020, was actively spreading and clinical trials in Brazil also had a success rate of more than 90% for the new variant, which is equivalent to the rate for the original variant.

“With the spread of mutated COVID-19 strains getting more serious, the FDA approval expands exports to overseas countries with this FDA approval,” a second Celltrion spokesperson said.

Co-developed with Humasis, the Diatrust COVID-19 Ag Rapid Test works by detecting nucleocapsid and receptor binding domains from SARS-CoV-2 in human nasopharyngeal swab specimens, with results available within 15 minutes.

“What distinguishes our test kit from other rapid diagnostic kits that generally only detect either the N or S antigen, is that the Diatrust COVID-19 Ag Rapid Test is a dual-antigen test kit that can detect both. Clinical trials in early-stage COVID-19 patients showed a sensitivity and specificity of 93.3% and 99.1%, respectively.

Meanwhile, Celltrion is also developing two more rapid test kits for COVID-19. The Diatrust COVID-19 IgG/IgM rapid test kit, also co-developed with Humasis, is a one-step in vitro diagnostic test based on an immunochromatographic assay which rapidly detects COVID-19 antibodies.

The second offering is the Sampinute COVID-19 Antigen MIA, co-developed this time with BBB Tech Inc.

The electrochemical immunoassay test detects the SARS-CoV-2 antigen from nasopharyngeal swab samples, includes a disposable use test cartridge and a portable analyzer.

Celltrion requested EUAs for both test kits in July 2020 and was also planning to launch second-generation rapid antibody and antigen diagnostic kits, also co-developed with Humasis. The kits will use Celltrion’s COVID-19 antibody-antiviral technology to enhance their detection sensitivity.

The FDA approval adds to what has already been a strong 2021 for Celltrion.

It has also received conditional marketing authorization from South Korea’s Ministry of Food and Drug Safety (MFDS) for its anti-COVID-19 monoclonal antibody, Regkirona (regdanvimab, also known as CT-P59) in February 2021. With this approval, Celltrion became the first company to receive approval for a COVID-19 antibody treatment developed in the country, said a MFDS spokesperson.

The company is currently conducting phase III clinical trials for Regkirona involving approximately 1,200 patients in around 10 countries suffering mild and moderate COVID-19. The drug is also currently being evaluated by the European Medicines Agency’s Committee for Medicinal Products for Human Use under a rolling review.

Outside its COVID-19 pipeline, the company continues to advance its biosimilar pipeline, and is current global phase III clinical trials. These include Xolair (omalizumab) biosimilar CT-P39 treating asthma and urticaria, Prolia (denosumab) biosimilar CT-P41 treating osteoporosis, Eylea (aflibercept) biosimilar CT-P42 treating diabetic macular edema and Stelara (ustekinumab) biosimilar CT-P43 treating psoriasis, Crohn's disease as well as ulcerative colitis.