By Mary Welch

Billing its Myeloid Progenitor Inhibitory Factor-1 (MPIF-1) as the first fully genomics-based drug to reach efficacy trials, Human Genome Sciences Inc. (HGS) began enrollment of a Phase II study with the drug in cancer patients.

"MPIF-1 is the first drug that came about through a review of all the genes," said Kate de Santis, spokeswoman for Rockville, Md.-based HGS.

The company would not disclose endpoints or how many breast or ovarian cancer patients or sites will be involved in the double-blind, placebo-controlled study, which is expected to last 12 to 18 months and will help identify appropriate doses and regimens for further studies.

"We have been in discussions with the FDA and are confident that we will gather sufficient data to get meaningful results."

MPIF-1 is a chemoprotectant that shields hematopoietic progenitor cells in the bone marrow from the effects of several chemotherapeutic agents used to treat major cancers. These agents work by killing rapidly growing cells, whether cancerous or not. A small portion of the early hematopoietic progenitor/stem cell population actively replaces blood cells that have reached the end of their life cycles.

When chemotherapeutic agents kill them, the body suffers from a lessening of neutrophils (the white blood cells that protect the body from infection), erythrocytes (red cells that carry oxygen) and megakaryocytes (the platelets necessary for clotting) - a condition known as myelosuppression, with which patients cannot survive for long.

In cell-based screens and in vivo studies, MPIF-1 seems to protect early progenitor cells from the toxic effects of chemotherapy. In addition, MPIF-1 accelerates the recovery of white blood cells and helps in the recovery of platelets.

MPIF-1, a member of the beta chemokine family, was discovered when HGS focused on more than 300 full-length human genes that correspond to proteins with apparent therapeutic potential. Through this research, the company discovered what it suspects are 23 new members of the chemokine/interleukin family.

HGS and Schering-Plough Corp., of Madison, N.J., along with SmithKline Beecham plc, of London, entered into a genomics collaboration and license agreement in 1996. In addition to license fee and product development milestone payments, Schering-Plough agreed to make payments totaling $55 million during the initial term of the collaboration. (See BioWorld Today, July 3, 1996, p. 1.)

As part of the agreement, Schering-Plough has the right to evaluate the clinical data on MPIF-1 and then decided whether to co-develop or co-market it. "We're still quite a while before that time comes," de Santis said.

She acknowledged that Amgen Inc., of Thousand Oaks, Calif., has advanced its native leptin program into Phase II studies, but Amgen licensed rights to that gene from Progenitor Inc., a spin-off of Interneuron Pharmaceuticals Inc., of Lexington, Mass. De Santis called MPIF-1 "a milestone, not only for our company, but for the industry."

HGS' stock (NASDAQ:HGSI) closed Wednesday at $33.937, up $1.062. n