Sponges: Nature’s Chemists
Sponges (phylum Porifera) are among the oldest multicellular animals on Earth. They live their entire adult lives attached to one spot, so they cannot escape predators, infection or competing organisms. Instead, they defend themselves chemically. That chemistry has made sponges one of the richest sources of new drug leads in nature.
From Sponge to Medicine
The field began in the early 1950s, when Bergmann and Feeney isolated unusual nucleosides from the Caribbean sponge Tethya crypta. These compounds led to two FDA-approved drugs: cytarabine, approved in 1969 for leukemia, and vidarabine, approved in 1976 as an antiviral. In 2010, FDA approved eribulin for metastatic breast cancer. Eribulin is a synthetic analog of halichondrin B, a compound first isolated from the marine sponge Halichondria okadai.
Two Barriers: Supply and Consistency
Most promising sponge compounds never reach patients, for two reasons.
The first is supply. Bioactive compounds occur in tiny amounts, and wild sponge populations are limited. Preclinical development of halichondrin B required more than one metric ton of sponge to yield 310 mg of pure compound. The sponge-derived drugs approved to date are made by chemical synthesis.
The second is consistency. The chemistry of a wild organism changes with its environment and its life cycle. The same species, harvested under different conditions, can yield very different material.
Villani’s Discovery
Maria Villani, a physician and sponge researcher, spent years testing freshwater sponges from protected reserves, looking for one with consistent biological activity. She identified a rare variant of the freshwater sponge Spongilla lacustris that grows in a remote National Reserve protected by UNESCO.
In Villani’s laboratory testing, the sponge’s compounds showed anti-inflammatory, anti-bacterial and anti-viral activity. They were not found in the other freshwater sponge species and variants Villani studied.
Solving Supply and Consistency
Most sponges grow slowly. This sponge completes its life cycle every year: it survives the winter as dormant gemmules and regrows each spring. That makes a renewable annual harvest possible, much like an agricultural crop.
Villani developed proprietary methods to harvest and process the sponge with batch-to-batch and year-to-year chemical consistency. Chemical studies at Scripps Institution of Oceanography investigated the consistency of sponge material harvested in different years.
Villani uses the whole sponge rather than isolating a single molecule, so no chemical synthesis is required.