HLA-Haploidentical donor lymphocyte infusions for patients with relapsed hematologic malignancies after related HLA-haploidentical bone marrow transplantation

Treatment of relapse after related HLA-haploidentical T cell-replete bone marrow transplantation (haploBMT) with post-transplantation cyclophosphamide (PTCy) using haploidentical donor lymphocyte infusion (haploDLI) is not documented. All patients who received haploDLI after haploBMT with PTCy between June 2003 and October 2012 were identified and assessed for graft-versus-host disease (GVHD) and outcomes. Forty patients received 52 haploDLI doses. Sixteen patients had acute myeloid leukemia, 11 had lymphomas, and 34 had nonmyeloablative conditioning before haploBMT. The median time from haploBMT to relapse was 183 (range, 0 to 1399) days. The median age at haploDLI was 48 (range, 3 to 70) years. The first haploDLI doses were 1×10⁵ CD3⁺ cells/kg with subsequent escalation. The most commonly used first haploDLI dose was 1×10⁶ CD3⁺ cells/kg. The median follow-up after haploDLI was 7 (mean, 15.4; range, .5 to 96) months for the entire cohort, and 17.5 (mean, 28; range, 2.4 to 96) months for the responders. Acute GVHD developed in 10patients (25%), 6 patients had grade 3 to 4, and 3 developed chronic GVHD. Twelve (30%) patients achieved a complete response (CR) with a median duration of 11.8 (mean, 22.5; range, .4 to 94) months. At last follow-up, 8 responders were alive in CR; 6 for over a year. HaploDLI for relapse after haploBMT is associated with acceptable toxicities and can result in durable responses.