P862: SERUM MASS SPECTROMETRY TO ANALYZE DISEASE RESPONSE IN PATIENTS WITH RELAPSED/REFRACTORY MULTIPLE MYELOMA RECEIVING ARI0002H, AN ACADEMIC BCMA-DIRECTED CAR T-CELL THERAPY. (23rd June 2022) - Ortiz De Landazuri, I.; Oliver-Caldés, A.; Español-Rego, M.; Contreras, M. T.; Zabaleta, A.; Agulló, C.; Puig, N.; Cabañas, V.; González-Calle, V.; Jiménez, R.; Inogés, S.; Rodríguez-Otero, P.; et al.