(UPDATED: See below.)

Archemix, a Cambridge, Mass., biotech developing drugs out of nucleic-acid chains called aptamers, filed to raise as much as $69 million in an initial offering.

The most interesting thing about Archemix is that it’s the latest in a string of companies that have sought to turn aptamers into drugs. It turns out nucleic acids, which usually carry genetic information, can also be engineered to trap or bind to particular molecules with fairly exquisite precision. Theoretically, at least, this would make aptamers equal, if not superior, to monoclonal antibodies, particularly since — again, in theory — they have other advantages, such as apparently being invisible to the immune system. The main problem is that aptamers haven’t yet proven particularly effective in practice. Only one aptamer has ever been approved as a drug — the blindness treatment Macugen — and it’s gotten walloped in the marketplace by Genentech’s Lucentis, which is a fragment of a monoclonal antibody.

Archemix, which generates some revenue by producing aptamer candidates for other biotech and pharma companies, has only one drug of its own in clinical trials, a potential anti-platelet treatment for blood clots called ARC1779 that’s just completed an early-stage trial.

UPDATE: I’ve expanded the item beyond the single-paragraph version that first appeared.

VB's research team is studying web-personalization... Chime in here, and we’ll share the results.