Celldex Therapeutics Plunges 10.36%: What's Behind the Sharp Drop and What's Next?

Summary
• Celldex Therapeutics (CLDX) tumbles 10.36% to $21.53, its lowest since 2022.
• Phase 2 EoE trial for barzolvolimab shows mast cell depletion but no clinical improvement.
• Webcast at 4:30 PM ET to discuss results and future pipeline.
• Intraday range of $21.10–$23.08 highlights volatile reaction to data.

Celldex Therapeutics faces a sharp selloff following underwhelming Phase 2 trial results for barzolvolimab in eosinophilic esophagitis (EoE). Despite robust mast cell depletion, the drug failed to improve symptoms, triggering investor skepticism. The stock’s 10.36% drop reflects immediate concerns over pipeline viability, though the company remains focused on other indications. Technical indicators and options activity suggest heightened volatility ahead.

Barzolvolimab's EoE Trial Fails to Show Clinical Benefit
Celldex’s barzolvolimab met its primary endpoint of mast cell depletion in EoE patients but showed no improvement in symptoms or endoscopic outcomes compared to placebo. The lack of clinical benefit, despite favorable safety data, led the company to halt EoE development. Investors interpreted this as a setback for the drug’s broader therapeutic potential, triggering a sell-off. The webcast today will clarify next steps, but the immediate reaction underscores skepticism about the program’s future in other GI indications.

Options and ETF Strategies Amid Volatility
• MACD: 0.655 (bullish divergence from signal line 0.394)
• RSI: 55.53 (neutral, avoiding overbought/oversold extremes)
• Bollinger Bands: $19.77 (lower band) vs. $25.87 (upper band), indicating wide-range consolidation
• 200D MA: $22.29 (current price below, suggesting bearish bias)

Technical indicators suggest CLDX is in a short-term bearish phase but remains within a long-term trading range. Key support levels at $21.88 (30D) and $20.33 (200D) could dictate near-term direction. The options chain reveals high volatility and liquidity in at-the-money puts, offering strategic entry points for short-term traders.

Top Option 1: CLDX20250919P21
• Type: Put
• Strike: $21
• Expiration: 2025-09-19
• IV: 54.58% (moderate)
• Leverage Ratio: 18.54% (high)
• Delta: -0.4217 (moderate sensitivity)
• Theta: -0.0073 (slow time decay)
• Gamma: 0.1154 (high sensitivity to price moves)
• Turnover: 11,920 (liquid)
• Payoff (5% downside): $0.53 per contract. This put offers leveraged exposure to a potential breakdown below $21, with high gamma amplifying gains if the stock gaps lower.

Top Option 2: CLDX20250919P22
• Type: Put
• Strike: $22
• Expiration: 2025-09-19
• IV: 50.88% (moderate)
• Leverage Ratio: 13.32% (high)
• Delta: -0.5450 (high sensitivity)
• Theta: -0.0019 (minimal time decay)
• Gamma: 0.1254 (very high sensitivity)
• Turnover: 8,925 (liquid)
• Payoff (5% downside): $1.07 per contract. This put is ideal for aggressive short-term bearish bets, with high gamma and leverage amplifying returns if CLDX breaks below $22.

Action: Aggressive bears should prioritize CLDX20250919P21 for a 5% downside target. Watch for a breakdown below $21.88 to confirm bearish momentum.

Backtest Celldex Therapeutics Stock Performance
The backtest of CLDX's performance after an intraday plunge of -10% shows favorable short-to-medium-term gains. The 3-Day win rate is 50.16%, the 10-Day win rate is 51.60%, and the 30-Day win rate is 51.44%, indicating a higher probability of positive returns in the immediate aftermath of such a significant downturn. The maximum return during the backtest period was 7.23%, which occurred on day 59, suggesting that while there is some volatility, CLDX can recover and even exceed its pre-plunge levels.

CLDX at Crossroads: Watch Webcast and Key Levels
Celldex’s near-term trajectory hinges on the webcast today and whether the stock breaks critical support levels. While the EoE trial halt is a setback, the company’s focus on chronic urticaria and other indications offers long-term potential. Investors should monitor the $20.33 (200D MA) and $19.77 (Bollinger lower band) levels for further bearish signals. Meanwhile, Amgen (AMGN), the sector leader, rose 0.65% today, highlighting broader biotech resilience. Act now: Short-term traders should prioritize the CLDX20250919P21 put if CLDX gaps below $21.10 at open.