Hello all, I am in my 4th year dealing with MM and now at age 84. After having been on four previous medications ( Velcade, Kyprolis, Daratumumab and Selinexor, all with the usual Dex and Lenalidomide or Pomalyst.)all which kept my MM in check. 8 weeks ago needed a change as these meds became resistant to treatment and did not allow me to reach remission. I am now on weekly injections of Elfrexio a BCMA-directed bispecific antibody drug. My labs have improved significantly. Could anyone share with me their side effects? I am terribly fatigued most of the day but more disappointing is the frequent Tachycardia when exercising forcing me to stop when my pulse exceeds 105. This is usually accompanied with a low systolic pressure, high diastolic pressure and of course the high pulse which many times exceeds my systolic pressure. It makes me totally useless. Any thoughts? Thank you Rudi