In a treat-and-extend dosing strategy, some patients may require frequent monthly injections to stabilize their disease, while others may demonstrate a more stable condition requiring infrequent treatments. Many clinicians who employ a treat-and-extend dosing regimen, do not extend their treatment intervals beyond 3 months. However, it is possible that the subgroup of patients on every three months 'treat-and-extend' dosing may represent a unique, stable population that would perform particularly well on a 'treat-and-observe' regimen.