Does Pfizer's Xeljanz share its CV safety questions with burgeoning JAK class?

Does Pfizer's Xeljanz share its CV safety questions with burgeoning JAK class?

Source: 
Fierce Pharma
snippet: 

Pfizer’s rheumatoid arthritis med Xeljanz, which already bears a black-box warning, has run into cardiovascular safety problems with its higher dose. Whether that dose stays on the market—and whether those safety troubles belong to the entire class of JAK inhibitors—remains to be seen.