Merrimack Pharmaceuticals, Inc, of Cambridge, Massachusetts, announced that it has raised $65 million in a Series E private equity financing to advance the company's lead product, MM-093, a recombinant version of human alpha-fetoprotein (hAFP), which is currently in phase II testing for rheumatoid arthritis (RA) and psoriasis. Merrimack, founded in 2000, has raised a total of $143 million in equity financing.

Merrimack has completed the enrollment of 258 patients into a randomized, double-blind, placebo-controlled, dose-ranging, multicenter, phase IIb study of once-weekly MM-093 by subcutaneous injection for 24 weeks, as an add-on to methotrexate, in patients with moderate-to-severe RA. The company has also initiated a double-blind, placebo-controlled, randomized, phase IIa pilot study of MM-093 in approximately 30 adult patients with moderate-to-severe chronic plaque psoriasis. Patients will receive double-blind treatment for 12 weeks, with a follow-up period of 6 weeks after the last dose. Results from the two studies are expected in mid to late 2006.
 
Alpha-fetoprotein (AFP) is an immunomodulatory serum protein normally produced at very high levels by fetuses and and is also present in low levels in the blood of adults and children. Research on AFP suggests that it may play a role in modulating the immune system of the mother in order to protect the developing fetus during pregnancy. The presence of hAFP in the pregnant mother's blood has long been associated with remission of many autoimmune diseases, including RA, psoriasis, and multiple sclerosis, during the third trimester of pregnancy.

— A. Techman