The graveyard related to safety issues - I don't think it matters that this is a different indication than for the previous drugs. The safety issues have been all over the place - hard to know if they are class effects or (perhaps more likely) because most of the molecules were built off the same scaffold if I recall correctly.
I will respectfully disagree. The article you linked to referenced the failure of p38 inhibitors in RA. RA is in no way an unmet medical need. There are plenty of effective treatments for RA. I don't see that as being the case for pain patients resistant to NSAIDs and who don't tolerate opioids. So, point is the safety bar is lower for an indication with an unmet need compared to those where there are plenty of effective treatments.