P899: REAL-WORLD ASSESSMENT OF TREATMENT PATTERNS AND OUTCOMES IN PATIENTS WITH LENALIDOMIDE-REFRACTORY RELAPSED/REFRACTORY MULTIPLE MYELOMA FROM THE OPTUM DATABASE. (23rd June 2022) - Dhakal, B.; Einsele, H.; Potluri, R.; Schecter, J.; Deraedt, W.; Lendvai, N.; Slaughter, A.; Lonardi, C.; Nair, S.; He, J.; Joseph, N.; Cost, P.; et al.