How to Trade FDA Catalysts: Run-Up, Binary Event, Exit

You found a biotech with a PDUFA date in six weeks. The drug looks promising, the chart is starting to move, and you want in. The problem: most retail traders buy the day before the decision, pay the full run-up premium, and then ride a coin flip. That is not a strategy. It is gambling with extra steps.

The solution: treat a PDUFA catalyst as a three-phase trade, enter during the quiet accumulation window, use the AdCom as your pre-signal, and have a written exit plan for all three outcomes before the date arrives.

Step 1: Map the three trade windows

Every biotech PDUFA catalyst moves through three distinct windows. Your job is to know which window you are in before you buy.

Window 1, Accumulation (6 to 12 weeks before PDUFA). The stock is quiet. The last catalyst is forgotten, the next one feels far away, and volume is low. This is where the edge lives. A drug that will trade at $12 on approval often sits at $5 or $6 here, and nobody is paying attention. If you have a thesis on the data, build a position here.

Window 2, Run-up (2 to 6 weeks before PDUFA). Speculators arrive. The stock climbs on no news, volume rises, and options premiums inflate. Most of the catalyst move, typically 60 to 80% of it, happens in this window, not on the decision day. Traders who bought in Window 1 are selling into Window 2 strength. Traders who buy in Window 2 are paying a premium for a smaller remaining move.

Window 3, Binary event (day before to day of PDUFA). The stock is priced for the outcome. Options are at maximum premium. This is the highest-risk, lowest-edge window. Buying here means you are betting on a coin flip, and the CRL base rate is 37% of all NDAs and BLAs between 2018 and 2022. Do not confuse this window with an opportunity.

Step 2: Size for a 50% loss before you size for a 50% gain

A single pre-PDUFA position should not exceed 2 to 5% of your portfolio. Biotech PDUFA dates are binary: the stock goes up 30 to 50% on approval or drops 30 to 60% on a CRL. One CRL on an oversized position can wipe out a year of gains.

If you cannot stomach a 50% loss on the position, the position is too big for a pre-PDUFA trade. This rule is non-negotiable. For a fuller framework on biotech position sizing and risk, see our guide to investing in biotech stocks.

Step 3: Use the AdCom as your pre-signal

An AdCom (advisory committee meeting) is a panel of outside experts that votes on whether to recommend approval. AdComs usually happen 4 to 8 weeks before the PDUFA date, and the vote is the single most actionable signal in the entire catalyst cycle.

• Positive vote (strong majority yes): Hold into the PDUFA. The FDA follows the panel the large majority of the time. The stock typically runs into the decision date.
• Negative vote (majority no): Exit immediately, not at the PDUFA. A negative AdCom vote roughly doubles the probability of a CRL. The stock drops on the vote and drops again on the CRL. Selling on the vote saves you the second leg down.
• Split or close vote: Reduce the position by half. A split vote signals genuine uncertainty, and uncertainty is what you are paid to take off the table.

Real example: Moderna (MRNA) went before an FDA AdCom on June 18, 2026 for its mRNA-1010 flu vaccine. The panel voted a unanimous 9 to 0 in favor of the benefit-risk profile. That vote was the signal. The PDUFA date is August 5, 2026, and by then the outcome is largely priced in. The trade was made on the AdCom vote, not the PDUFA. For the mechanics of how PDUFA dates and AdComs are set, see our PDUFA date guide.

Step 4: Choose your instrument, stock or options

Stock is simplest. Options give you amplified exposure and defined risk, but they are also where retail traders lose the most money in biotech.

Long calls for the run-up. Buy out-of-the-money or at-the-money calls expiring after the PDUFA date during Window 1 or early Window 2. You get magnified exposure to the run-up with defined risk (the premium paid). If the catalyst fails, your loss is capped at the premium.

Long puts as a hedge. If you are holding stock through the binary event and want protection, buying puts caps your downside. This is insurance, not a directional bet.

Straddle or strangle for high-uncertainty catalysts. When you expect a big move but do not know the direction, a straddle (buying both a call and a put at the same strike) profits from volatility in either direction. These are expensive because the market knows the catalyst is coming, so premiums are rich.

Never sell options into a binary event. Selling calls or puts into a PDUFA is the most dangerous trade in biotech. A CRL can gap the stock down 50%, and a short call holder takes the full loss. Defined-risk long options are the only sane options approach for catalysts.

Step 5: Have a written exit plan for all three outcomes

Before the PDUFA date, write down what you will do in each scenario. Not after the headline. Before.

1. Approval. The stock gaps up 20 to 80% on approval, sometimes more for small caps with no approved drugs. Take 50 to 70% of profits immediately on the gap. Let the remaining position run with a trailing stop. Biotech stocks often peak on approval day and fade 20 to 30% in the following week as speculators exit. “Buy the rumor, sell the news” is the dominant pattern. For a clean example of how an approval-day move plays out, see our Madrigal resmetirom MASH approval writeup.

2. CRL (Complete Response Letter). Exit the full position immediately on the open. Do not average down. Do not tell yourself “it will get approved on resubmission.” The base rate of second-try approval is well below 50%, and the resubmission cycle takes 12 to 18 months of cash burn. A CRL is the end of that trade, not the beginning of the next one. The CRL guide covers the typical 30 to 60% single-day drop and why holding through a CRL is the costliest mistake in biotech.

3. Extension. The FDA pushes the PDUFA date, usually by 3 months, to review new data or process a major amendment. The stock typically drops 10 to 20%, not 50%. A delay is not a CRL. If your thesis on the data is intact, hold. If the extension signals the FDA found a problem you did not anticipate, reduce. Selling an extension at a 40% loss turns a temporary delay into a permanent loss.

Common mistakes

• Buying the day before the PDUFA. You pay the full run-up premium to bet on a binary outcome with a 37% CRL base rate. The edge is in the run-up, not the decision.
• Ignoring the AdCom vote. A negative AdCom vote is your exit signal. Waiting for the CRL to sell means selling 40% lower than the post-AdCom price.
• Over-sizing positions. One CRL on a 20% position can wipe out a year. Max 2 to 5% per pre-PDUFA play.
• Selling options into the binary event. Undefined risk on a stock that can move 50% in either direction overnight. This is how accounts blow up.
• Treating an extension as a CRL. A 3-month delay is the FDA asking for more time. Panic-selling locks in a loss on a position that may still get approved.
• Not reading the trial data. The PDUFA is the date; the data is the reason. If you cannot read a clinical trial press release, you are gambling, not investing.

Final checklist

• PDUFA date confirmed from company press release or BioPharmCatalyst
• AdCom date on the calendar if scheduled
• Position sized to 2 to 5% of portfolio
• Entry window identified (accumulation or early run-up, not the day before)
• Exit plan written for approval, CRL, or delay
• Trial data read and thesis documented
• Not selling options into the binary event