Criteria for “Transient” vs. “Persistent” should be based on the natural clearance of endogenous human Ig. If ADA are predominantly IgG1/2/4, ADA response lasting > 16 weeks can be considered as Persistent. This is because t1/2 is 21-25 days, So 97% of the IgG would have been eliminated after 5 half-lives (16 weeks).