What is your preferred induction regimen prior to allo-HCT for mantle cell lymphoma?

I commonly use a reduced-intensity conditioning regimen before alloSCT for patients with MCL especially since most of these patients have received prior autoSCT, are older, and are heavily treated. I try to incorporate low dose TBI in the regimen such as TBI 200 cGy x 2 sessions in one day. Frequent...