Immunotherapy with CD25/CD71-allodepleted T cells to improve T-cell reconstitution after matched unrelated donor hematopoietic stem cell transplant: a randomized trial.

BACKGROUND AIMS: Delayed immune reconstitution is a major challenge after matched unrelated donor (MUD) stem cell transplant (SCT). In this randomized phase 2 multi-center trial, Adoptive Immunotherapy with CD25/71 allodepleted donor T cells to improve immunity after unrelated donor stem cell transplant (NCT01827579), the authors tested whether allodepleted donor T cells (ADTs) can safely be used to improve immune reconstitution after alemtuzumab-based MUD SCT for hematological malignancies. METHODS: Patients received standard of care or up to three escalating doses of ADTs generated through CD25+/CD71+ immunomagnetic depletion. The primary endpoint of the study was circulating CD3+ T-cell count at 4 months post-SCT. Twenty-one patients were treated, 13 in the ADT arm and eight in the control arm. RESULTS: The authors observed a trend toward improved CD3+ T-cell count at 4 months in the ADT arm versus the control arm (230/µL versus 145/µL, P = 0.18), and three ADT patients achieved normal CD3+ T-cell count at 4 months (>700/µL). The rates of significant graft-versus-host disease (GVHD) were comparable in both cohorts, with grade ≥2 acute GVHD in seven of 13 and four of eight patients and chronic GVHD in three of 13 and three of eight patients in the ADT and control arms, respectively. CONCLUSIONS: These data suggest that adoptive transfer of ADTs is safe, but that in the MUD setting the benefit in terms of T-cell reconstitution is limited. This approach may be of more use in the context of more rigorous T-cell depletion.

Enhanced CAR T cell expansion and prolonged persistence in pediatric patients with ALL treated with a low-affinity CD19 CAR.

Chimeric antigen receptor (CAR)-modified T cells targeting CD19 demonstrate unparalleled responses in relapsed/refractory acute lymphoblastic leukemia (ALL)1-5, but toxicity, including cytokine-release syndrome (CRS) and neurotoxicity, limits broader application. Moreover, 40-60% of patients relapse owing to poor CAR T cell persistence or emergence of CD19- clones. Some factors, including the choice of single-chain spacer6 and extracellular7 and costimulatory domains8, have a profound effect on CAR T cell function and persistence. However, little is known about the impact of CAR binding affinity. There is evidence of a ceiling above which increased immunoreceptor affinity may adversely affect T cell responses9-11. We generated a novel CD19 CAR (CAT) with a lower affinity than FMC63, the high-affinity binder used in many clinical studies1-4. CAT CAR T cells showed increased proliferation and cytotoxicity in vitro and had enhanced proliferative and in vivo antitumor activity compared with FMC63 CAR T cells. In a clinical study (CARPALL, NCT02443831 ), 12/14 patients with relapsed/refractory pediatric B cell acute lymphoblastic leukemia treated with CAT CAR T cells achieved molecular remission. Persistence was demonstrated in 11 of 14 patients at last follow-up, with enhanced CAR T cell expansion compared with published data. Toxicity was low, with no severe CRS. One-year overall and event-free survival were 63% and 46%, respectively.

Phase III trial of high-dose sequential chemotherapy with peripheral blood stem cell support compared with standard dose chemotherapy for first-line treatment of advanced ovarian cancer: intergroup trial of the AGO-Ovar/AIO and EBMT.

PURPOSE: Although ovarian cancer is one of the most chemotherapy-sensitive solid tumors, cure after radical surgery and chemotherapy is uncommon. A randomized trial comparing high-dose sequential chemotherapy with peripheral blood stem cell (PBSC) support with platinum-based combination chemotherapy was conducted to investigate whether dose-intensification improves outcome. PATIENTS AND METHODS: One hundred forty-nine patients with untreated ovarian cancer were randomly assigned after debulking surgery to receive standard combination chemotherapy or sequential high-dose (HD) treatment with two cycles of cyclophosphamide and paclitaxel followed by three cycles of HD carboplatin and paclitaxel with PBSC support. HD melphalan was added to the final cycle. The median age was 50 years (range, 20 to 65 years) and International Federation of Gynecology and Obstetrics stage was IIb/IIc in 4%, III in 78%, and IV in 17%. RESULTS: Seventy-six percent of patients received all five cycles in the HD arm and the main toxicities were neuro-/ototoxicity, gastrointestinal toxicity, and infection and one death from hemorrhagic shock. After a median follow-up of 38 months, the progression-free survival was 20.5 months in the standard arm and 29.6 months in the HD arm (hazard ratio [HR], 0.84; 95% CI, 0.56 to 1.26; P, .40). Median overall survival (OS) was 62.8 months in the standard arm and 54.4 months in the HD arm (HR, 1.17; 95% CI, 0.71 to 1.94; P, .54). CONCLUSION: This is the first randomized trial comparing sequential HD versus standard dose chemotherapy in first-line treatment of patients with advanced ovarian cancer. We observed no statistically significant difference in progression-free survival or OS and conclude that HD chemotherapy does not appear to be superior to conventional dose chemotherapy.