Rezolute's 88% Plunge: A Biotech Meltdown After Failed Phase 3 Trial

Summary
• Rezolute (RZLT) shares plummeted 88.16% intraday, trading at $1.295 after a catastrophic Phase 3 trial miss.
• The sunRIZE study for congenital hyperinsulinism failed to meet primary and key secondary endpoints, with 45% vs. 40% placebo improvement.
• Management hosts a conference call today at 8:30am ET to address next steps under FDA Breakthrough Therapy Designation.

Rezolute’s stock imploded on December 11, 2025, as the market digested the failure of its flagship Phase 3 sunRIZE trial. The stock’s intraday range—from $1.07 to $1.41—highlighted extreme volatility, while the 52-week low of $1.07 now looms as a critical support level. This collapse underscores the fragility of biotech valuations in the face of clinical setbacks.

Phase 3 Trial Misses Mark, Sending Shares Into Freefall
Rezolute’s 88% intraday plunge was triggered by the sunRIZE trial’s failure to meet its primary endpoint—a 45% reduction in hypoglycemia events at the top dose (10 mg/kg) compared to a 40% placebo improvement, which was not statistically significant. The key secondary endpoint, measuring time in hypoglycemia via CGM, also fell short, with a 25% reduction in the drug arm versus a 5% placebo increase. While management highlighted favorable safety data and plans to engage the FDA, the lack of statistical significance in efficacy metrics shattered investor confidence. The company’s admission of disappointment and reliance on future meetings with regulators left the market with no immediate catalysts to justify a rebound.

Biotech Sector Mixed as AMGN Gains 0.82%
While Rezolute’s shares collapsed, the broader biotech sector showed resilience. Amgen (AMGN), a sector leader, rose 0.82% on the day, reflecting divergent investor sentiment. ETFs like the iShares Biotech ETF (XBI) gained 0.93%, and the Direxion Daily Biotech Bull 3X Shares (LABU) surged 2.52%, indicating a flight to perceived safer plays. Rezolute’s failure contrasts with peers benefiting from positive clinical reads or regulatory momentum, underscoring the sector’s high-risk, high-reward nature.

Navigating the Aftermath: ETFs and Technicals in a Bearish Play
• Technical Indicators: 200-day MA at $6.07 (far above current price), RSI at 57.5 (neutral), MACD at 0.205 (bullish divergence).
• Key Levels: 52-week low at $1.07 (critical support), 30-day support at $9.50 (now irrelevant).
• ETFs: SBIO (+1.19%) and XBI (+0.93%) offer exposure to biotech resilience, while LABU (3X leveraged) amplifies sector moves.

Rezolute’s technicals suggest a short-term bearish bias, with the RSI hovering near neutral and the MACD hinting at potential divergence. The 52-week low at $1.07 is a critical psychological level to watch, as a break below could trigger further selling. For aggressive traders, LABU offers leveraged exposure to sector rebounds, while SBIO and XBI provide more conservative plays. Given the lack of options liquidity, ETFs remain the primary vehicle for positioning.

Backtest Rezolute Stock Performance
The backtest of RZLT's performance after an intraday plunge of -88% from 2022 to now shows mixed results. While the stock experienced a significant decline, it also exhibited a strong recovery, with maximum returns of 16.80% over various time frames.

A Crucial Crossroads: Watch for FDA Moves and upLIFT Data
Rezolute’s collapse highlights the binary nature of biotech investing, where clinical outcomes dictate valuations. While the sunRIZE failure is a major setback, the company’s plans to engage the FDA and the pending upLIFT trial results in tumor HI (H2 2026) offer faint hope. Investors should monitor the 8:30am ET conference call for regulatory strategy updates and watch the 52-week low at $1.07 for potential support. Meanwhile, sector leaders like AMGN (+0.82%) suggest broader biotech resilience. For now, the path forward hinges on regulatory flexibility and the upLIFT trial’s ability to deliver a lifeline.