High CD34-positive cell dose in matched unrelated donor allogeneic hematopoietic stem cell transplant is not associated with graft-versus-host disease or mortality.

BACKGROUND: CD34+ stem cells serve as the primary graft source for allogeneic transplants, with a minimum of 2-4 × 106 cells/kg needed for engraftment. There are conflicting data on outcomes at high stem cell doses, with studies limited by few patients receiving doses far above the minimum target. STUDY DESIGN AND METHODS: In this retrospective, single-center study of patients with hematologic malignancies who underwent matched unrelated donor transplants, we assessed outcomes for engraftment, survival, relapse, and graft-versus-host disease (GVHD) for the highest CD34+ dose quintile (>13 × 106 cells/kg, n = 36) compared to the remaining patients (n = 139). Similar analysis was performed correlating T cell dose and outcomes. RESULTS: There was no difference between the groups in neutrophil engraftment, with a trend toward faster platelet engraftment. There was no significant difference in mortality (adjusted risk ratio [aRR] = 1.02, 95% confidence interval [CI] = 0.85-1.22), relapse (aRR = 1.10, 95% CI = 0.85-1.42), or overall survival by Kaplan-Meier analysis (p = .44). High CD34+ dose was not associated with higher incidence of acute GVHD (aRR = 0.99 grades II-IV, aRR = 1.18 grades III-IV) or chronic GVHD (aRR = 0.87 overall, RR = 1.21 severe). There was limited correlation between CD34+ and T cell dose (R2 = .073), and there was no significant difference in survival, relapse, or GVHD in the highest T cell dose quintile (n = 33) compared to the remaining quintiles (n = 132). DISCUSSION: We found no difference in survival, relapse, or GVHD incidence or severity in patients receiving CD34+ doses above prior cutoffs reported in the literature. These data do not support the routine use of graft CD34+ dose reduction.

Plain language summary of the TRANSFORM study primary analysis results: liso-cell as a second treatment regimen for large B-cell lymphoma following failure of the first treatment regimen.

What is this summary about? People diagnosed with a disease called large B-cell lymphoma (LBCL) may experience return, or early relapse, of their disease within the first year after receiving and responding to their first (first-line) treatment regimen. Others may have primary refractory disease, meaning that the disease either did not respond to first-line treatment at all or only responded for a very brief period. Second (second-line) treatment includes immunotherapy followed by high-dose chemotherapy and ASCT, which has the potential to cure LBCL. However, if the disease does not respond to immunotherapy, people cannot receive ASCT, and less than 30% of people are cured.Therefore, new second-line treatment options are required, such as CAR T cell therapy, which uses a person's own genetically engineered lymphocytes, also called T cells, to fight their lymphoma. In this article, we summarize the key results of the phase 3 TRANSFORM clinical study that tested if liso-cel, a CAR T cell treatment, can safely and effectively be used as a second-line treatment for people with early relapsed or primary refractory (relapsed/refractory) LBCL.A total of 184 adults with relapsed/refractory LBCL who were able to receive ASCT were randomly treated with either liso-cel or standard of care (SOC) as second-line treatment. SOC included immunochemotherapy followed by high-dose chemotherapy and ASCT.What were the key takeaways? Almost all (97%) people in the liso-cel group completed treatment, whereas 53% of people in the SOC group did not complete treatment, mostly due to their disease not responding or relapsing, and therefore they were not able to receive ASCT. People who received liso-cel as a second-line treatment lived longer without the occurrence of an unfavorable medical event or worsening of the disease and had a better response to treatment than those who received SOC as second-line treatment. People who received liso-cel reported side effects that researchers considered to be manageable, and that were known to occur with CAR T cell treatment.What were the main conclusions reported by the researchers? Results from the TRANSFORM study support the use of liso-cel as a more effective second-line treatment compared with SOC that is safe for people with relapsed/refractory LBCL.Clinical Trial Registration: NCT03575351 (TRANSFORM study) (ClinicalTrials.gov).

Five-year follow-up of a phase 2 study of ibrutinib plus fludarabine, cyclophosphamide, and rituximab as initial therapy in CLL.

ABSTRACT: We previously reported high rates of undetectable minimal residual disease <10-4 (uMRD4) with ibrutinib plus fludarabine, cyclophosphamide, and rituximab (iFCR) followed by 2-year ibrutinib maintenance (I-M) in treatment-naïve chronic lymphocytic leukemia (CLL). Here, we report updated data from this phase 2 study with a median follow-up of 63 months. Of 85 patients enrolled, including 5 (6%) with deletion 17p or TP53 mutation, 91% completed iFCR and 2-year I-M. Five-year progression-free survival (PFS) and overall survival were 94% (95% confidence interval [CI], 89%-100%) and 99% (95% CI, 96%-100%), respectively. No additional deaths have occurred with this extended follow-up. No difference in PFS was observed by immunoglobulin heavy-chain variable region gene status or duration of I-M. High rates of peripheral blood (PB) uMRD4 were maintained (72% at the end of iFCR, 66% at the end of 2-year I-M, and 44% at 4.5 years from treatment initiation). Thirteen patients developed MRD conversion without clinical progression, mostly (77%) after stopping ibrutinib. None had Bruton tyrosine kinase (BTK) mutations. One patient had PLCG2 mutation. Six of these patients underwent ibrutinib retreatment per protocol. Median time on ibrutinib retreatment was 34 months. The cumulative incidence of atrial fibrillation was 8%. Second malignancy or nonmalignant hematologic disease occurred in 13%, mostly nonmelanoma skin cancer. Overall, iFCR with 2-year I-M achieved durably deep responses in patients with diverse CLL genetic markers. Re-emergent clones lacked BTK mutation and retained sensitivity to ibrutinib upon retreatment. This trial is registered at www.clinicaltrials.gov as #NCT02251548.