Cidara Therapeutics (CDTX) Stock Double as Merck Nears $9.2 Billion Acquisition

TLDR

• Cidara Therapeutics stock surged nearly 100% in premarket trading on Merck acquisition news
• Merck is paying $221.50 per share in cash, valuing Cidara at up to $9.2 billion
• The deal represents nearly triple Cidara’s previous $3.3 billion market capitalization
• Cidara’s CD388 flu prevention drug showed 76% efficacy in mid-stage trials
• The transaction could be finalized as soon as Friday, November 14, 2025

Cidara Therapeutics shares exploded nearly 100% in premarket trading Thursday. The biotech company accepted a $9.2 billion acquisition offer from Merck.

Cidara Therapeutics, Inc., CDTX

Merck is paying $221.50 per share in all-cash. The price represents a massive premium over Cidara’s recent trading levels.

The deal could be announced officially as soon as Friday, November 14, 2025. Sources close to the matter confirmed the transaction late Thursday evening.

Cidara’s market capitalization stood at approximately $3.3 billion before the acquisition talks became public. Merck’s offer values the company at nearly triple that amount.

Bidding War Drives Premium Valuation

Merck faced competition from at least one other pharmaceutical company. The rival bidder was still pursuing Cidara late Thursday before the company accepted Merck’s superior offer.

The competitive bidding process drove up Cidara’s valuation. Multiple pharmaceutical giants recognized the value of the company’s experimental drug pipeline.

Premarket trading showed Cidara shares reaching approximately $208 per share. This represents a dramatic jump from the company’s previous closing price.

The acquisition centers entirely on Cidara’s CD388 drug candidate. This experimental therapy offers a novel approach to flu prevention.

CD388 Clinical Success Attracts Buyer Interest

CD388 demonstrated up to 76% protection against influenza in mid-stage clinical trials. These results positioned the drug as a potential game-changer in flu prevention.

The therapy uses long-acting antibodies rather than traditional vaccine technology. Patients would receive a single dose instead of annual flu shots.

CD388 is designed to provide season-long protection. The drug specifically targets high-risk patients who face severe complications from influenza.

The FDA granted CD388 breakthrough therapy designation in October 2025. This status accelerates the drug development and regulatory review timeline.

Breakthrough therapy designation applies only to drugs addressing serious conditions with limited treatment options. The FDA recognition validated CD388’s potential impact.

The drug prevents both influenza A and B strains. This universal protection distinguishes CD388 from strain-specific vaccines.

Merck’s offer includes both upfront cash and milestone-based payments. Additional payments would trigger when CD388 hits specific clinical trial benchmarks.

The milestone payment structure protects Merck if clinical development faces setbacks. It also gives Cidara shareholders upside if the drug exceeds expectations.

Cidara declined to comment on the acquisition reports. Merck has not responded to media requests for confirmation.

The $221.50 per share cash offer provides immediate liquidity to Cidara shareholders. The deal eliminates the risk of continued independent operations for the small biotech.

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