Older acute myeloid leukemia (AML) patients have a poor prognosis; therefore, novel therapies are needed. Allogeneic natural killer (NK) cells have been adoptively transferred with promising clinical results. Here, we report the first-in-human study exploiting a unique scalable NK-cell product generated from CD34 hematopoietic stem and progenitor cells (HSPC) from partially HLA-matched umbilical cord blood units. Ten older AML patients in morphologic complete remission received an escalating HSPC-NK cell dose (between 3 and 30 × 10/kg body weight) after lymphodepleting chemotherapy without cytokine boosting. HSPC-NK cell products contained a median of 75% highly activated NK cells, with <1 × 10 T cells/kg and <3 × 10 B cells/kg body weight. HSPC-NK cells were well tolerated, and neither graft-versus-host disease nor toxicity was observed. Despite no cytokine boosting being given, transient HSPC-NK cell persistence was clearly found in peripheral blood up to 21% until day 8, which was accompanied by augmented IL15 plasma levels. Moreover, donor chimerism up to 3.5% was found in bone marrow. Interestingly, HSPC-NK cell maturation was observed, indicated by the rapid acquisition of CD16 and KIR expression, while expression of most activating receptors was sustained. Notably, 2 of 4 patients with minimal residual disease (MRD) in bone marrow before infusion became MRD negative (<0.1%), which lasted for 6 months. These findings indicate that HSPC-NK cell adoptive transfer is a promising, potential "off-the-shelf" translational immunotherapy approach in AML. .

Patients with MYC-rearrangement positive large B-cell lymphoma (MYC+ LBCL) have an inferior prognosis following standard first-line therapy with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) as compared to patients without MYC rearrangement. Although intensive chemotherapy regimens yield higher remission rates, toxicity remains a concern. Lenalidomide is an oral immunomodulatory drug which downregulates MYC and its target genes thereby providing support using lenalidomide as additional therapeutic option for MYC+ LBCL. A phase II trial was conducted evaluating the efficacy of lenalidomide (15 mg day 1-14) in combination with R-CHOP (R2CHOP) in newly diagnosed MYC+ LBCL patients identified through a nationwide MYC-FISH screening program. The primary endpoint was complete metabolic response (CMR) on centrally reviewed 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)-computer tomography (CT)-scan at end-of-treatment. Secondary endpoints were overall survival (OS), disease-free survival (DFS) and event-free survival (EFS). Eighty-two patients with stage II-IV MYC+ LBCL were treated with 6 cycles of R2CHOP. At EOT, 67% (confidence interval (CI) 58-75%) of the patients reached CMR. With a median follow-up of 25.4 months, 2-year estimates (95% CI) for OS, DFS, EFS were 73% (62-82%), 75% (63-84%) and 63% (52-73%) respectively. In this prospective trial for newly diagnosed MYC+ LBCL patients, we found that administering R2CHOP was safe, and yields comparable CMR and survival rates as in studies applying more intensive chemotherapy regimens. Hence, these findings offer new prospects for MYC+ LBCL patients and warrant comparison in prospective randomized clinical trials. This trial was registered at www.clinicaltrialsregister.eu (#2014-002654-39).

Rituximab‐containing induction followed by autologous stem cell transplantation (ASCT) is the standard first‐line treatment for young mantle cell lymphoma patients. However, most patients relapse after ASCT. We investigated in a randomised phase II study the outcome of a chemo‐immuno regimen and ASCT with or without maintenance therapy with bortezomib. Induction consisted of three cycles R‐CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone), two cycles high‐dose cytarabine, BEAM (carmustine, etoposide, cytarabine, melphalan) and ASCT. Patients responding were randomised between bortezomib maintenance (1·3 mg/m 2 intravenously once every 2 weeks, for 2 years) and observation. Of 135 eligible patients, 115 (85%) proceeded to ASCT, 60 (44%) were randomised. With a median follow‐up of 77·5 months for patients still alive, 5‐year event‐free survival (EFS) was 51% (95% CI 42–59%); 5‐year overall survival (OS) was 73% (95% CI 65–80%). The median follow‐up of randomised patients still alive was 71·5 months. Patients with bortezomib maintenance had a 5‐year EFS of 63% (95% CI 44–78%) and 5‐year OS of 90% (95% CI 72–97%). The patients randomised to observation had 5‐year PFS of 60% (95% CI, 40–75%) and OS of 90% (95% CI 72–97%). In conclusion, in this phase II study we found no indication of a positive effect of bortezomib maintenance after ASCT.

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Introduction Elderly acute myeloid leukemia (AML) patients have a poor prognosis due to high relapse rates following standard therapy. Natural Killer (NK) cell alloreactivity has found to control relapse in AML in the HLA-mismatched haploidentical allogeneic stem cell transplantation (allo-SCT) setting. Moreover, allogeneic NK cell infusions can induce complete remission (CR) inpatients with advanced AML. As a consequence, adoptive NK cell transfer may be a promising treatment for elderly AML patients, who are not eligible for allo-SCT. Most clinical studies exploited NK cell products enriched from leukapheresis of haploidentical donors containing low numbers of T cells that could have contributed to the observed therapeutic effects and potentially induced graft-versus-host disease (GVHD). Therefore, we have developed a GMP-compliant culture system for the generation of large batches of NK cells from umbilical cord blood (UCB)-derived CD34+ progenitor cells, without T cell contamination. Here, we report results of a phase I dose escalation study (Dutch Trial Register nr. NTR2818) to evaluate the feasibility, safety and toxicity of allogeneic UCB-NK cell infusion following an immunosuppressive preparative regimen in elderly AML patients. Secondary endpoints were NK cell lifespan and the effects on minimal residual disease (MRD). Methods Elderly AML patients not eligible for allo-SCT, and in morphologic CR after standard therapy, were given preparative chemotherapy consisting of Cyclophosphamide (Cy;900 mg/m2/day) and Fludarabine (Flu;30 mg/m2/day) on days -6 to -2. At day 0, UCB-NK cells at a dose of 3, 10 or up to 30x106/kg body weight were infused without IL-2 treatment to study if in vivo expansion could be obtained without IL-2 support. Patients were assessed for toxicity and GVHD. Donor chimerism was measured by Q-PCR for discriminating DNA polymorphisms. NK cell expansion and phenotype were analyzed by flow cytometry. MRD was evaluated by flow cytometry and molecular techniques. Results Twelve AML patients (68-76 years) have been included, all in morphologic CR after 2 to 3 standard chemotherapy courses (n=6), or 1 standard chemotherapy course followed by subsequent treatment with hypomethylating agents (azacitidine or decitabine) (n=6). Patients were treated with Cy/Flu and an escalating dose of partially HLA-matched UCB-NK cells. Four patients had good/intermediate risk, 4 poor risk and 4 very poor risk AML. To date, 9 patients received NK cell products containing a median of 74% highly activated CD56+ NK cells, with <1x104/kg CD3+ T cells and <3x105/kg CD19+ B cells. Remaining non-NK cells were CD14+ and/or CD15+ monocytic and myelocytic cells. Follow up did not show GVHD or toxicity attributed to the NK cells. As expected, preparative Cy/Flu induced a neutropenic period of 20 ± 16 days, but no severe infections were seen. A temporary repopulation and persistence of UCB-NK cells could be detected in peripheral blood between days 1 and 8 post-infusion, which was associated with increased IL-15 plasma levels observed in most patients. Interestingly, donor chimerism increased with higher doses of infused UCB-NK cells, and donor chimerism up to 3.5% was found in bone marrow (BM) at day 7/8. Further UCB-NK cell maturation in vivo was observed by acquisition of CD16 and KIRs, while expression of activating receptors was sustained. Of the 9 treated patients so far, 5 (56%) are still in CR after 43, 35, 31, 5 and 4 months, whereas 4 patients relapsed after 5, 6 (2 pts) and 15 months. Despite morphologic CR during azacitidine treatment, residual disease of 6-7% with a leukemia-associated phenotype could be detected by flow cytometry before NK cell infusion in BM of two patients. In both patients MRD was reduced to less than 0.05% at 90 days after UCB-NK cell therapy following Flu/Cy conditioning. Conclusion These results show that GMP-compliant UCB-NK cell products containing up to 30x106 NK cells/kg body weight can be safely infused in non-transplant eligible AML patients following immunosuppressive chemotherapy. After infusion, UCB-NK cells repopulate, mature and migrate to BM without supporting IL-2 infusion. Since we observed reduction in MRD in patients on treatment with hypomethylating agents, this UCB-NK cell therapy may induce or sustain CR in elderly AML patients, and could serve as an alternative consolidation therapy for patients with refractory AML or provide bridge to allo-SCT. Disclosures Spanholtz: Glycostem Therapeutics: Employment. Tordoir:Glycostem Therapeutics: Employment. Bohme:Glycostem Therapeutics: Employment. Kok:Glycostem Therapeutics: Employment.