What happened Shares of ChemoCentryx (NASDAQ: CCXI) were crashing 46.5% lower as of 3:06 p.m. EDT on Tuesday. The huge decline came after the U.S. Food and Drug Administration (FDA) released briefing documents for an advisory committee scheduled to meet on Thursday to review the approval application for avacopan. So what As you might have guessed from the collapse of the biotech stock today, the FDA's briefing documents didn't look very good for ChemoCentryx. Instead, the documents raised significant doubts about the prospects for avacopan to win approval in treating anti-neutrophilic cytoplasmic autoantibody (ANCA)-vasculitis, an autoimmune disease that causes small blood vessels to swell. Image source: Getty Images. The FDA stated in the briefing documents that ChemoCentryx's study design on which its regulatory filing is based "raise questions about the interpretability of the data to define a clinically meaningful benefit of avacopan." That basically means that the agency doesn't put much stock in the clinical results for the experimental drug. This shouldn't have been much of a surprise to ChemoCentryx, though. The FDA stated that it previously informed the company about many of its concerns about the design of the late-stage study for avacopan. Now what It's possible that the Arthritis Advisory Committee will still view ChemoCentryx's filing for avacopan in a positive light. That doesn't seem likely at this point, though, considering the strong language the FDA included in its briefing documents. Even if the advisory committee recommends approval, the agency doesn't have to go along with that recommendation. ChemoCentryx could very well have to conduct another late-stage study to address the FDA's concerns. 10 stocks we like better than ChemoCentryxWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and ChemoCentryx wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of February 24, 2021 Keith Speights has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source