n the early days of bio-tech, all eyes focused on the techniques of "recombinant DNA": splicing together bits of DNA from different sources. These 30-year-old genetic engineering methods are now the basis of a multibillion-dollar market for protein-based drugs. Today, another class of biotech drugs is emerging from the lab, but the technology for these "antisense therapies" isn't new-it dates back to 1978, just a few years after the first gene-splicing experi-ments. A few persistent researchers have shepherded it down a long, bumpy road.

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