LONDON  Peptide Therapeutics Group plc released positive trial results for both its Phase II compounds last week, and said it now will seek pharmaceutical partners.

Gordon Cameron, finance director, told BioWorld International, ¿These things always take longer than expected, but I would expect to see some revenue as a result of signing a deal within the next six months.¿

The trial data are related to Peptide¿s oral typhoid vaccine, the rights to which were acquired from Medeva plc and on which Medeva has first refusal, and a rye grass hay fever vaccine, on which SmithKline Beecham has first refusal. Cameron said that as yet there is no indication from either company whether they intend to take up the options. ¿We have not discussed this with them until the results came out, but have agreed to present the data once we have full reports. We hope to present soon to Medeva, but it will be a couple of months before we get the full report on the hay fever trial. If they don¿t take them up, there will be others who will, because we have got good Phase II data.¿

Medeva has rights to revenue-sharing arrangements if Peptide licenses the Salmonella typhi vaccine to a third party.

The announcement had little effect on the stock price, which fell by 3 percent last week to 79 pence (US$1.30). ¿The share price has not risen recently despite a run of positive news because the market knows we need to raise money,¿ said Cameron. ¿Institutional investors are waiting for the fund raising before they put any more money in.¿

The fund raising is a condition of Peptide¿s merger with OraVax Inc., and will proceed once the merger is approved by shareholders later this month. Cameron said it was not yet clear how much will be raised, but the aim would be to secure sufficient funding to see the company through to profitability. At present, there is #10 million (US$16.4 million) in cash, sufficient for just under 12 months.

The positive results for the oral typhoid vaccine are particularly important because Peptide, based in Cambridge, also intends to use the genetically engineered S. typhi as a carrier for other antigens in the development of further oral vaccines. It already has one project using S. typhi as a vector for a Helicobacter pylori vaccine which is due to enter Phase I clinical trials this year.

The randomized, double-blind crossover trial comparing two doses of the live, attenuated oral typhoid vaccine CVD 908-htrA was co-sponsored by the National Institute of Allergy and Infectious Diseases in the U.S. Eighty adult outpatients were followed at the Center for Vaccine Development at the University of Maryland at Baltimore.

Both dose levels of the vaccine were highly immunogenic, eliciting both a mucosal and a systemic response. Cells secreting IgA antibodies against S. typhi lipopolysaccharide (LPS) antigen were isolated from the blood of 92 percent of the low-dose patients and 100 percent of the high-dose subjects. In addition, 59 percent of the low-dose and 77 percent of the high-dose subjects raised serum IgA LPS antibodies. Peptide says these findings indicate that the orally administered vaccine elicits a strong mucosal response. Assays of cell-mediated immunity are still under way.

Serum IgG responses to LPS antigen were detected in approximately 50 percent of the subjects. This response to a single dose compares favorably with the only currently licensed oral typhoid vaccine, Ty21a, which requires three or four separate doses.

Both doses of vaccine were well tolerated, with the incidence of symptoms following vaccination not significantly higher than that following placebo. No bacteremia (live organisms) was observed in any volunteer.

The company said the results provide ¿an excellent basis¿ for the further development of the vaccine for use by travelers and in populations where typhoid is endemic.

They also support the use of the S. typhi technology as a carrier for other antigens in the development of oral vaccines to raise a mucosal immune response. The technology already is being applied in the development of an oral H. pylori vaccine, in collaboration with Pasteur Merieux-OraVax.

Cameron said, ¿This result gives us the confidence to put more resources into the S. typhi technology. We are always on the lookout for other antigens, and would partner on a project-by-project basis, rather than licensing this as a technology platform.¿

The trial of the tolerizing peptide for the prevention of hay fever caused by rye grass involved 129 patients at four centers in the U.K. during the 1998 hay fever season. The patients were divided into moderate or severe sufferers using a skin reaction test. The results showed that in severely allergic patients there was a clear reduction in the combined hayfever symptom and medication score and a delay in the use of medication. There was no such effect in moderately allergic patients. There were no side effects in either group. Hay fever affects 15 percent to 20 percent of the U.K. population.

Cameron said, ¿It would have been great if it had worked in everyone. But sufferers of severe hay fever are more likely to use a vaccine because their symptoms cannot be controlled with existing treatments such as antihistamines. So it is the right population for the vaccine to have worked in.¿ n

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