The rheumatoid arthritis market has exploded in recent years, producing some of big pharma's best-selling blockbuster drugs. AbbVie's (ABBV -0.30%) Humira hit sales of more than $9 billion to lead the market last year, but competitors from other companies -- such as Johnson & Johnson's (JNJ -1.15%) Remicade, which hauled in more than $6 billion last year to rank among the top drugs in the industry -- have thrived in a crowded but lucrative immunology field.

Humira faces a patent expiration soon, however, and competition continues to heat up in this space. GlaxoSmithKline (GSK 0.12%) is the latest firm to eye the arthritis market after it agreed to a licensing deal with German biotech firm MorphoSys (MPSYF -1.83%) this week for its developmental immunology therapy MOR103. Glaxo's pipeline is sizable and solid, but will this deal brew another blockbuster for the firm's future? Motley Fool contributor Dan Carroll and health care analyst Max Macaluso discuss what you need to know.