T Cell Sciences Inc. and SmithKline Beecham plc announcedTuesday that they have filed an investigational new drug (IND)application with the FDA to begin clinical trials this fall of TCell's compound sCR1.

sCR1 is the first of a new class of compounds, calledcomplement inhibitors, developed to minimize tissue damagethat occurs in life-threatening inflammatory and autoimmunediseases.

"There is clearly a large potential for the sCR1 complementinhibitor in very acute diseases for which there is currently notreatment," said Allan Tuck, president and chief executive of TCell Sciences.

The complement system is a family of disease-fighting proteinsin the bloodstream that when activated trigger the release ofinflammatory mediators, including attraction of white bloodcells to the affected site, an increase in blood vesselpermeability and direct cell-killing activity.

Normally these events play a valuable role in eliminating anddestroying damaged tissue. But complement activation canresult in the destruction of nearby healthy tissue or tissue thatmight otherwise recover.

sCR1 is a soluble, recombinant version of a naturally occurringreceptor protein that acts as a co-factor with Factor I inregulating activated complement. sCR1 binds to the activatedcomplement and inhibits the range of complement-mediatedreactions, which can be fatal.

According to Jeff Casdin, an analyst with Oppenheimer & Co. inNew York, the animal data involving sCR1 that has beenpresented so far is impressive, and he's optimistic that humantrials of sCR1 will be successful.

Competition in the field is limited, as T Cell Sciences holds thebasic patent position for the complement receptor area, Tucktold BioWorld. The potential U.S. patient market forcomplement inhibitor is almost 2 million for the followingdiseases and conditions: organ transplant, renal dialysis, adultrespiratory disease (ARDS), cardiopulmonary bypass,gomerulonephritis and lupus, and post-heart attack reperfusioninjury.

Under the terms of their November 1989 agreement,SmithKline will fund clinical development of the compound inreturn for exclusive, worldwide marketing rights. At certainsales levels, T Cell Sciences will receive co-promotional rights inthe U.S. and royalties on worldwide sales.

Initial clinical trials of sCR1 will be conducted in burn patientsat risk of developing ARDS, a life-threatening disorder thatannually affects about 250,000 patients in the U.S. Respiratoryfailure resulting from complement activation is a major causeof death in burn patients.

"The complement pathway is an important element in animmune system, and there's nothing out there other than thiscompound to inhibit it," said Casdin.

The company is also studying other compounds for use ascomplement inhibitors, including Compinact A and Compinact C,which may selectively inhibit parts of the complementpathway, and TK9C, a synthetic organic compound that may beadministered orally. Tuck said he could not predict when thesecould be expected to be ready to enter pre-clinical trials.

T Cell Sciences of Cambridge, Mass., is utilizing its proprietary Tcell and soluble receptor technology to develop drugs to treatinflammation and autoimmune diseases, and cancer.

The company's stock (NASDAQ:TCEL) closed at $8 a share onTuesday, up 38 cents.

-- Michelle Slade Associate Editor

(c) 1997 American Health Consultants. All rights reserved.