P1573: VARIATION IN USE OF IMMUNOGLOBULIN AND IMPACT ON SURVIVAL IN MULTIPLE MYELOMA: A REPORT FROM THE AUSTRALIA/NEW ZEALAND (ANZ) AND ASIA-PACIFIC (APAC) MYELOMA AND RELATED DISEASES REGISTRIES (MRDR). (23rd June 2022) - Chai, K. L.; Wellard, C.; Aoki, N.; Moore, E. M.; Augustson, B.; Bapat, A.; Blacklock, H. A.; Chng, W. J.; Cooke, R.; Forsyth, C.; Hamad, N.; Harrison, S. J.; et al.