Qiagen Ups Bid for Cellestis by 7% with Eye on QuantiFERON Diagnostics Platform

Disease detection and monitoring technology includes whole-blood lab tests for TB and CMV infections.

Qiagen has upped its offer to acquire Australian diagnostics firm Cellestis to A$3.80 per share, a 7% increase on the original offer of A$3.55 per share announced in April, which would have put the overall purchase price at A$341 million in cash. The firm says the A$3.80 per share offer won’t be increased further in the absence of a competing bid, and represents a 33.1% premium on the one-month volume-weighted average of Cellestis’ shares the day before the initial offer was made public.

Qiagen is looking to buy Cellestis to get its hands on the latter’s QuantiFERON® technology for disease detection and monitoring, including its clinical-use QuantiFERON-TB Gold (QFT) blood test for diagnosing Mycobacterium tuberculosis infection, and QuantiFERON-CMV test for cytomegalovirus infection. The CMV test has been CE-marked in Europe but is currently only available for research use in the U.S.

The QuantiFERON platform has been developed as a whole-blood method for detecting cell-mediated immune responses to an existing infection or disease. The in-tube technology exploits the fact that individuals exposed to a specific disease have circulating T cell lymphocytes in their blood that maintain an immunological memory. A whole-blood sample from the patient is challenged with a disease antigen. If the disease is already present, antigen challenge stimulates effector T cells to release the cytokine interferon-gamma (IFN-γ), which the QuantiFERON technology detects. Effectively the production of IFN-γ in response to antigen exposure acts a specific marker of recall response, indicating that the disease or infection was already present, Cellestis explains.

In addition to its existing TB and CMV tests, the firm is currently developing a QuantiFERON test for detecting Leishmania parasite infection. Cellestis reported revenues of $22.5 million in the six months prior to December 2010, up 24% from revenues in the equivalent six months of 2009.