Pharmaceutical company

The Setup
Your client is a multinational pharmaceutical and biologics company. The client has a portfolio of drugs for major disease areas, including cancer, cardiovascular, and gastrointestinal diseases, to name a few. The client has experienced a decline in revenue over the last 18 months, and is fearful of further declines, especially given that its most commercially successful drug, which treats acid reflux disease, will be going off of patent in May of next year

Questions
What are the areas they should look into to change the course of this trend?
Which Drug is the largest source of revenue decline? What is the biggest loss?
Provide possible sources of client’s issues