Yesterday, ZymoGenetics Inc (ZGEN) announced that its rheumatoid arthritis drug Atacicept, failed to reach its goal of controlling the disease in mid-stage studies. The data did not support a direct move to late-stage trials. However, the study confirmed the biological effect of Atacicept, and did not display any unexpected side effects.

Atacicept is being developed in collaboration with Merck Serono S.A. (formerly Serono S.A.), an affiliate of Merck KGaA, Darmstadt, Germany.  Under this agreement, ZymoGenetics will co-promote Atacicept with Merck Serono in the US, while Merck Serono will promote Atacicept ex-US.

In view of the disappointing results, Merck Serono has not decided whether the late-stage trials will be conducted.

Atacicept is also being developed for other indications such as lupus and multiple sclerosis.

As a reminder, Recombinant human thrombin (rhThrombin, Recothrom) was approved by the U.S. Food and Drug Administration (FDA) on January 17, 2008. The product  is indicated for use as a topical hemostat to control moderate bleeding during surgical procedures.

Recothrom is identical in amino acid sequence and structurally similar to naturally occurring human thrombin. It is the first recombinant, plasma-free thrombin approved for use as a topical hemostat. The product is not derived from animal or human blood.

Recothrom competes with Thrombin-JMI, a bovine (cattle-derived) plasma derived thrombin from King Pharmaceuticals (KG) and EviThrom, a human plasma derived thrombin from Omrix Pharmaceuticals which are derived from plasma.

ZymoGenetics recently filed a Citizen Petition (CP) with the FDA requesting the agency to remove King Pharmaceuticals’ Thrombin-JMI from the market in the interest of patient safety. ZymoGenetics filed the CP based on reports of serious or fatal bleeding-related events in surgical patients exposed to bovine thrombin.

We believe that rhThrombin has advantages over existing plasma-derived thrombin products. All human plasma-derived products carry an FDA warning addressing the potential risk of transmitting infectious and other diseases such as HIV and hepatitis.

A recombinant human form of thrombin is inherently free from these potential risks and is not expected to have a “black box” warning or be associated with the risk of transmitting blood-borne pathogens or infectious diseases. We also believe that rhThrombin can be handled and stored more conveniently as compared to a human plasma-derived thrombin.
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