Verona Pharma plc (VRNA)

Verona Pharma plc was a biopharmaceutical company founded in 2005 and based in London, with U.S. operations in Raleigh, North Carolina. It focused on developing and commercializing treatments for chronic respiratory diseases with high unmet need, most prominently chronic obstructive pulmonary disease. Its ordinary shares were listed in London on AIM, and in 2017 the company listed American depositary shares on Nasdaq under the symbol VRNA.

The company's lead asset was ensifentrine, a first-in-class inhaled compound that inhibits both phosphodiesterase 3 and phosphodiesterase 4. By acting on both enzymes, it provides bronchodilator and non-steroid anti-inflammatory effects in a single molecule. Development included a nebulized formulation, and the company also explored dry powder inhaler and pressurized metered-dose inhaler versions.

Verona advanced ensifentrine through Phase 3 trials known as ENHANCE-1 and ENHANCE-2 in COPD patients. The company also pursued a collaboration in China, licensing rights to a partner in that market.

The U.S. Food and Drug Administration approved ensifentrine under the brand name Ohtuvayre in June 2024 as a maintenance treatment for COPD, marking the first new inhaled mechanism of action for the disease in many years. Verona built its own U.S. commercial organization to market the nebulized product. Sales grew through 2024 and 2025 as prescriptions expanded.

In July 2025, Merck announced a definitive agreement to acquire Verona Pharma for $107.00 per ADS in cash, each ADS representing eight ordinary shares. The transaction carried a total value of approximately $10 billion and was structured as a UK scheme of arrangement. Merck viewed Ohtuvayre as a complement to its respiratory and cardiopulmonary portfolio.

Verona's shareholders and the High Court of Justice in England and Wales approved the scheme, and the other closing conditions were met. MSD announced completion of the acquisition on October 7, 2025, after which Verona Pharma became a wholly owned subsidiary of Merck. The company's ADSs stopped trading on Nasdaq, and a Form 25 delisting notice was filed with the Securities and Exchange Commission that day.

Holders of ADSs received $107.00 per ADS in cash, equal to about $13.38 per underlying ordinary share. Following completion, Verona's former listings ended, and the company no longer files reports as an independent public issuer.