Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of gastrointestinal drug developer NPS Pharmaceuticals (Nasdaq: NPSP) canceled a large order of antacids this morning after spiking as much as 13.6% on moderate volume.

So what: This stock tends to move in small batches, but a couple of very large trades were pushed through in the first five minutes of today's trading. There's no news of any kind to explain the big buys; we're simply watching the big boys at play in a small stock.

Now what: The last time NPS made a seemingly inexplicable move, a Japanese partner had just submitted a leukemia drug for regulatory review. And that submission had absolutely nothing to do with the NPS partnership. Recently, the stock has suffered from American health-care worries, not helped even by a significant earnings beat in the second quarter or a renewed licensing deal with pharma giant GlaxoSmithKline (NYSE: GSK).

So nothing changed today other than a short-lived price boost for a handful of lucky sellers. As with fellow biotech developers cast from the same mold as Dendreon (Nasdaq: DNDN) and Cell Therapeutics (Nasdaq: CTIC), NPS investors are hanging on the success or failure of new drugs going through FDA approvals -- and there's no news (good or bad) to report on that front.

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