LONDON -- Antisoma plc, of London, which is focused on development of tumor-targeting cancer treatments, said it will float on the Easdaq Pan-European exchange, raising up to £10 million (US$16.5 million). The money will be used for clinical studies, in particular for Theragyn, a treatment for ovarian cancer now in Phase III trials.

Existing investors have agreed to subscribe for a third of the new shares, and following the placing the expected market capitalization will be £25 million to £30 million.

Glyn Edwards, CEO of Antisoma, told BioWorld International that the company needed to raise more money, and was thinking of doing this through a private placement.

"Earlier in the year, we decided to stay private for a bit longer," Edwards said. "But when we talked to institutions throughout Europe, the reaction was that we should go public. They pointed out that it was unusual for a company with a product in Phase III not to be on a public market."

Edwards said the decision to float on Easdaq rather than on the home market was not related to the poor state of biotechnology stocks on the London Stock Exchange. "Biotechnology is as out of favor in the rest of Europe as it is in London," Edwards said. "All the non-specialist investors have pulled out. However, the specialists are still there, and we decided to go for Easdaq because it is still fairly small and we thought we would get a higher a profile.

"There's no doubt that this is a difficult time to raise money, however, and wherever you do it," Edwards added. "But we have very supportive shareholders, and we have had interest from new institutions."

Antisoma had little choice about the timing. The last round of funding, in January 1997, raised £8.5 million. "We said that would last two years and it has," Edwards said. "The burn rate has not increased much, and we expect the £10 million we are raising now to last two years."

The company licenses products from cancer charities, universities and other biotechnology companies for further development, aiming to license them out at late-stage development. "We don't have high capital needs; we are not a research powerhouse," Edwards said. "If we see an opportunity we grab it, and if we need more money for a good product, the wider shareholder base should enable us to raise it."

The Phase III trial of Theragyn, a monoclonal antibody that delivers radioactive yttrium-90 to kill cancer cells, will complete recruitment of 300 patients by the end of 1999. The endpoint is two-year survival, so the data will not be available until 2001. However, Edwards said, he is confident of doing a marketing deal for Theragyn, which originated at the Imperial Cancer Research Fund, by the middle of 1999.

In the Phase II trial, the projected five-year survival rate of Theragyn-treated patients was 80 percent, compared to 55 percent for the control group. Antisoma said that results from ovarian cancer studies to date indicate that Theragyn may be effective in treating the intra-abdominal spread of other epithelial cancers, and the company is now planning a Phase I/II trial of Theragyn in gastric cancer to start early in 1999.

The next product in the portfolio is TheraFab, which is derived from the same antibody as Theragyn, and is designed for targeting cancer outside the abdominal cavity. The first candidate, a radiolabeled antibody to be used in conjunction with radiotherapy to treat breast or lung cancer, will enter Phase I/II late in 1999. Another product, AngioMab, a radiolabeled monoclonal antibody that targets new blood vessels that grow to supply tumors, is expected to enter Phase I/II for the treatment of glioblastoma (cancer of the brain) in 2000. In addition, the company owns rights to Pepscan, an imaging agent for cancer diagnosis.

There are three other products in the preclinical phase, including one for targeted apoptosis. This is an antibody linked to DNAase, an enzyme which destroys cancer cells, but, unlike the radiolabeled compounds, is not toxic to the rest of the body.

"We do need to fatten the pipeline, and are looking for things that could leapfrog," Edwards said. "There are a lot of compounds out there; at the moment we are looking at 10, but will probably say no to nine of them. There's no shortage of good candidates." *