Tanox Biosystems Inc. said its anti-immunoglobulin E(IgE) monoclonal antibody achieved positive results inPhase II studies for treatment of hay fever caused bymountain cedar pollen.

The Phase II studies involved 155 patients at threemedical centers in Texas. The participants were dividedinto a placebo and three treatment groups, which receiveddifferent dosage levels of the drug, called CGP 51901.All participants also could receive chlorpheniramine asrescue medication.

Frances Davis, director of project administration forHouston-based Tanox, said the data showed themonoclonal antibody achieved statistical significance atall doses compared with placebo (and chlorpheniramine)in reducing reliance on the rescue medication and nasalsymptoms, such as runny and itchy nose and sneezing.CGP 51901 is a chimeric monoclonal antibody derivedfrom mice and genetically engineered with humanproteins.

The treatment was judged "generally safe," howeverDavis added that one patient experienced a seriousadverse reaction attributed to CGP 51901 and anothertreated patient developed antibodies to the drug.

Unlike other monoclonal antibodies made to be antigenspecific in treating allergies, Tanox's drug removes fromthe blood stream the IgE and IgE-producing B cellsresponsible for triggering the allergic reactions caused bynumerous antigens.

If CGP 51901 works for hay fever sufferers, Davis said, itmay also be effective for people allergic to dogs, cats,dust mites, cockroaches and other forms of pollen.

Tanox, a privately held company developing the drugwith Basel, Switzerland-based Ciba-Geigy Ltd., chose totarget IgE because studies showed it is not essential forhealth and because high levels of the protein are related toallergy severity.

Davis said the Phase II studies for hay fever demonstratedthe drug's performance was highly significant in greatlyreducing reliance on the rescue medication at the highestdosage level. One-fourth of the patients in that treatmentgroup needed no other medication. In the placebo groupall patients required chlorpheniramine.

Participants in the trial were selected based on theirhistory of severe allergic reaction to mountain cedar,which pollinates in December and January in Texas. Thestudies began in November 1994 and participants wereenrolled in the trials as they developed their allergiesthrough natural exposure to the pollen. The patients weretreated for 12 weeks.

Based on the findings in the hay fever studies, Davis saidPhase II trials in allergic asthma are slated to begin nextyear. n

-- Charles Craig

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