While working on a vaccine to prevent urinary tract infections (UTIs), MedImmune Inc. has outlicensed exclusive rights to similar technology for developing antibiotics against gram-negative diseases to Siga Pharmaceuticals Inc. for 335,530 Siga shares.

Based on Thursday's closing price for Siga stock (NASDAQ:SGPH) of $4.25, down $0.25, the deal is worth $1.42 million.

The technology was developed at Washington University, in St. Louis, and relates to pili, the fine hairs that cover many bacteria and attach to the host tissue, said Mark Kaufmann, spokesman for Gaithersburg, Md.-based MedImmune.

"It's all generated from the same labs and the same discoveries," Kaufmann said.

"Our vaccine strategy is fairly simple," he added. "We found that antibodies against the tip of the pili blocked attachment and blocked the [infection]." (See BioWorld Today, April 25, 1997, p. 1.)

UTIs are caused by Escherichia coli bacteria. One of every two American women suffers the painful burning urination of a UTI at least once in her life, and one in 10 has three to five recurrences per year. The problem accounts for 7 million to 8 million doctor visits or hospitalizations annually, at a cost exceeding $1 billion.

The technology acquired by Siga relates to assembly of bacterial pili.

"We've characterized the assembly process and determined the crystal structure of the proteins, and developed tests to screen for compounds against those proteins," Kaufmann told BioWorld Today. "If you can block those proteins and inhibit the assembly of the pili, you would have a new class of antibiotics."

MedImmune's stock (NASDAQ:MEDI) closed Thursday at $51, up $3.25. — Randall Osborne