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What: Shares of Halozyme Therapeutics (NASDAQ:HALO) plunged 26% on Friday after the company announced that it is temporarily halting patient enrollment and dosing of PEGPH20 in an ongoing Phase 2 trial (Study 202) evaluating the drug in patients with pancreatic cancer.

So what: Management said it is taking the "precautionary actions" in response to a recommendation from an independent data monitoring committee, or DMC, suggesting that PEGPH20's path to approval will be all the more challenging. So while the stock had pulled back sharply in recent weeks on the general biotech malaise, today's bad news raises specific concerns about Halozyme's growth trajectory.

Now what: Management said it will continue working with the DMC to get PEGPH20 back on track. "Patient safety is our first priority," said President and CEO Dr. Helen Torley in a press release. "We will be providing additional information to the DMC as quickly as possible so they can complete their assessment and we can determine next steps." Foolish investors should monitor developments closely and research the company's pipeline and collaboration arrangements carefully before making an investment decision.

Brian Pacampara has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.