What's average amount of time people can take biologics (ex: humira (adalimumab) or enbrel) before developing an immunity to it? Do all patients develop immunity?

See below. Patients are more apt to develop resistance to biologic if they are not on methotrexate. However; not all patients are candidate to be on methotrexate. Some patients never have a problem and some do. It is hard to comment on the average amount of time because it is an individual phenomena.