The acquisition of Bellus Health, which is developing a specialty drug for chronic cough, is a strategic move by GSK to strengthen its portfolio of medicines. The deal represents the company's largest acquisition since the separation of its 'consumer health' division last year and demonstrates the company's commitment to expanding its pharmaceutical portfolio.

Bellus Health is currently conducting pivotal human studies to determine the effectiveness of its drug, Kamlipixant, in reducing chronic cough. The disease, which affects approximately 28 million people in the United States, Japan, China and key European markets, has prompted several companies to develop drugs that target sensory receptors in the upper airways to prevent triggering the cough reflex. Kamlipixant would complement GSK's current respiratory portfolio, which includes successful products such as Nucala and Trelegy. Together, these products generated sales in excess of $3.7 billion last year.

Although GSK is actively pursuing acquisitions to strengthen its drug portfolio, it lags behind many of its competitors in terms of cash reserves. Merck, for example, recently announced the acquisition of Prometheus Biosciences for a sizeable $10.8 billion, while Pfizer made headlines last month with the industry's largest deal in four years when it acquired oncology biotech Seagen for a total enterprise value of $43 billion.

Shares in Bellus health (BLU) nearly doubled on the stock market on Tuesday. Shares rose 98.9% to close at $14.44. GSK shares, on the other hand, fell 1.6% to end the regular session at $36.78.