Sea sponges aren't only handy in the bath.
They could also provide doctors with a new generation of drugs to treat serious diseases, including cancer.
Tapping natural chemicals in sponges and other marine creatures first grabbed the imagination of researchers in the 1970s, when Swiss group Roche Holding AG explored Australia's Great Barrier Reef -- without success.
But bio-prospecting is a slow business and, a quarter of a century on, the underwater treasure hunt is starting to yield results, with several marine pharmaceutical compounds now nearing the market.
Ireland's Elan Corp plans to launch a new painkiller shortly that will be the first ever drug isolated from a marine organism, according to David Newman, a chemist in the natural products branch of the National Cancer Institute in Maryland.
The compound, called Prialt, comes from a tropical cone snail that stabs its prey with a poison harpoon. It is designed to treat severe chronic pain in cancer and AIDS patients.
Clearance hopes
The novel analgesic won conditional approval from the US Food and Drug Administration last year and an Elan spokesman said the company hoped for final clearance later this year.
Behind it, the Spanish biotechnology company PharmaMar, a unit of Zeltia SA set up specifically to comb the sea for drugs, expects to start selling its first anti-cancer compound, known by the codename ET-743, by the end of next year in Europe.
The drug, extracted from a grape-like sea squirt cultivated in the Mediterranean, is collected by divers, although a semi-synthetic version is also in development.
Zeltia has a further two cancer drugs in clinical trials, the most advanced of which -- Aplidine -- is showing promise.
There is nothing particularly new about tapping nature's medicine chest -- the ancient Egyptians first recorded the use of medicinal plants almost 4,000 years ago.
Modern medicine, too, has embraced a variety of natural products including the heart drug digitalis, originally made from foxglove; blood pressure treatments derived from viper venom; and a cancer medicine, Taxol, extracted from yew trees.
But it is only relatively recently that researchers have looked systematically to the sea -- despite some serendipitous discoveries that have helped in drug design. It was analysis of chemicals in Caribbean sponges in the 1950s, for example, that gave vital chemical clues needed to make the AIDS drug AZT.
Newman, a world expert on drugs from the sea, believes there are good reasons to think marine invertebrates, particularly those found in tropical seas and on coral reefs, will yield powerful new drugs, including tumor-killing agents.
Chemical `arms race'
Sponges and other creatures are engaged in a chemical "arms race" in their watery environment, and they need potent defenses to counteract the natural dilution of the sea.
"On a coral reef what you have is chemical warfare. Every invertebrate needs to have a toehold on the reef so it can feed and the way to defend that toehold is to develop a more powerful poison sack than the competition," said Newman.
"That is why materials from the marine environment are normally extremely potent."
Zeltia chairman Jose-Maria Fernandez Sousa-Faro says his company has collected 22,000 marine samples since 1986 and he is confident there are many more new drugs among them.
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