Pfizer and Allergan have agreed to join together to form the world’s biggest pharma company. Pfizer is paying US$160,000 for the company best known for its Botox products. The new entity will be known as Pfizer. The friendly deal will see Pfizer’s Ian Read as chief executive and chairman, and Allergan’s Brent Saunders as president and chief operating officer. Pfizer failed last year in a bid to take over UK-based AstraZeneca.