Peter E. Westerweel

Successful Transfer of Umbilical Cord Blood CD34+ Hematopoietic Stem and Progenitor-derived NK Cells in Older Acute Myeloid Leukemia Patients

Purpose: 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 ex vivo from CD34+ hematopoietic stem and progenitor cells (HSPC) from partially HLA-matched umbilical cord blood units. Experimental Design: Ten older AML patients in morphologic complete remission received an escalating HSPC-NK cell dose (between 3 and 30 × 106/kg body weight) after lymphodepleting chemotherapy without cytokine boosting. Results: HSPC-NK cell products contained a median of 75% highly activated NK cells, with <1 × 104 T cells/kg and <3 × 105 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, in vivo 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. Conclusions: These findings indicate that HSPC-NK cell adoptive transfer is a promising, potential “off-the-shelf” translational immunotherapy approach in AML. Clin Cancer Res; 23(15); 4107–18. ©2017 AACR.

Phase 1/2 study of lenalidomide combined with low-dose cyclophosphamide and prednisone in lenalidomide-refractory multiple myeloma.

The prognosis of multiple myeloma (MM) patients who become refractory to lenalidomide and bortezomib is very poor, indicating the need for new therapeutic strategies for these patients. Next to the development of new drugs, the strategy of combining agents with synergistic activity may also result in clinical benefit for patients with advanced myeloma. We have previously shown in a retrospective analysis that lenalidomide combined with continuous low-dose cyclophosphamide and prednisone (REP) had remarkable activity in heavily pretreated, lenalidomide-refractory MM patients. To evaluate this combination prospectively, we initiated a phase 1/2 study to determine the optimal dose and to assess its efficacy and safety in lenalidomide-refractory MM patients. The maximum tolerated dose (MTD) was defined as 25 mg lenalidomide (days 1-21/28 days), combined with continuous cyclophosphamide (50 mg/d) and prednisone (20 mg/d). At the MTD (n = 67 patients), the overall response rate was 67%, and at least minimal response was achieved in 83% of the patients. Median progression-free survival and overall survival were 12.1 and 29.0 months, respectively. Similar results were achieved in the subset of patients with lenalidomide- and bortezomib-refractory disease as well as in patients with high-risk cytogenetic abnormalities, defined as t(4;14), t(14;16), del(17p), and/or ampl(1q) as assessed by fluorescence in situ hybridization. Neutropenia (22%) and thrombocytopenia (22%) were the most common grade 3-4 hematologic adverse events. Infections (21%) were the most common grade 3-5 nonhematologic adverse events. In conclusion, the addition of continuous low-dose oral cyclophosphamide to lenalidomide and prednisone offers a new therapeutic perspective for multidrug refractory MM patients. This trial was registered at www.clinicaltrials.gov as #NCT01352338.

Discontinuation of tyrosine kinase inhibitor therapy in chronic myeloid leukaemia (EURO-SKI): a prespecified interim analysis of a prospective, multicentre, non-randomised, trial

BACKGROUND Tyrosine kinase inhibitors (TKIs) have improved the survival of patients with chronic myeloid leukaemia. Many patients have deep molecular responses, a prerequisite for TKI therapy discontinuation. We aimed to define precise conditions for stopping treatment. METHODS In this prospective, non-randomised trial, we enrolled patients with chronic myeloid leukaemia at 61 European centres in 11 countries. Eligible patients had chronic-phase chronic myeloid leukaemia, had received any TKI for at least 3 years (without treatment failure according to European LeukemiaNet [ELN] recommendations), and had a confirmed deep molecular response for at least 1 year. The primary endpoint was molecular relapse-free survival, defined by loss of major molecular response (MMR; >0·1% BCR-ABL1 on the International Scale) and assessed in all patients with at least one molecular result. Secondary endpoints were a prognostic analysis of factors affecting maintenance of MMR at 6 months in learning and validation samples and the cost impact of stopping TKI therapy. We considered loss of haematological response, progress to accelerated-phase chronic myeloid leukaemia, or blast crisis as serious adverse events. This study presents the results of the prespecified interim analysis, which was done after the 6-month molecular relapse-free survival status was known for 200 patients. The study is ongoing and is registered with ClinicalTrials.gov, number NCT01596114. FINDINGS Between May 30, 2012, and Dec 3, 2014, we assessed 868 patients with chronic myeloid leukaemia for eligibility, of whom 758 were enrolled. Median follow-up of the 755 patients evaluable for molecular response was 27 months (IQR 21-34). Molecular relapse-free survival for these patients was 61% (95% CI 57-64) at 6 months and 50% (46-54) at 24 months. Of these 755 patients, 371 (49%) lost MMR after TKI discontinuation, four (1%) died while in MMR for reasons unrelated to chronic myeloid leukaemia (myocardial infarction, lung cancer, renal cancer, and heart failure), and 13 (2%) restarted TKI therapy while in MMR. A further six (1%) patients died in chronic-phase chronic myeloid leukaemia after loss of MMR and re-initiation of TKI therapy for reasons unrelated to chronic myeloid leukaemia, and two (<1%) patients lost MMR despite restarting TKI therapy. In the prognostic analysis in 405 patients who received imatinib as first-line treatment (learning sample), longer treatment duration (odds ratio [OR] per year 1·14 [95% CI 1·05-1·23]; p=0·0010) and longer deep molecular response durations (1·13 [1·04-1·23]; p=0·0032) were associated with increasing probability of MMR maintenance at 6 months. The OR for deep molecular response duration was replicated in the validation sample consisting of 171 patients treated with any TKI as first-line treatment, although the association was not significant (1·13 [0·98-1·29]; p=0·08). TKI discontinuation was associated with substantial cost savings (an estimated €22 million). No serious adverse events were reported. INTERPRETATION Patients with chronic myeloid leukaemia who have achieved deep molecular responses have good molecular relapse-free survival. Such patients should be considered for TKI discontinuation, particularly those who have been in deep molecular response for a long time. Stopping treatment could spare patients from treatment-induced side-effects and reduce health expenditure. FUNDING ELN Foundation and France National Cancer Institute.

Treatment outcome in a population-based, ‘real-world’ cohort of patients with chronic myeloid leukemia

Evaluations of the ‘real-world’ efficacy and safety of tyrosine kinase inhibitors in patients with chronic myeloid leukemia are scarce. A nationwide, population-based, chronic myeloid leukemia registry was analyzed to evaluate (deep) response rates to first and subsequent treatment lines and eligibility for a treatment cessation attempt in adults diagnosed between January 2008 and April 2013 in the Netherlands. The registry covered 457 patients; 434 in chronic phase (95%) and 15 (3%) in advanced disease phase. Seventy-five percent of the patients in chronic phase were treated with imatinib and 25% with a second-generation tyrosine kinase inhibitor. At 3 years 44% of patients had discontinued their first-line treatment, mainly due to intolerance (21%) or treatment failure (19%). At 18 months 73% of patients had achieved a complete cytogenetic response and 63% a major molecular response. Deep molecular responses (MR4.0 and MR4.5) were achieved in 69% and 56% of patients, respectively, at 48 months. All response milestones were achieved faster in patients treated upfront with a second-generation tyrosine kinase inhibitor, but ultimately patients initially treated with imatinib also reached similar levels of responses. The 6-year cumulative incidence of eligibility for a tyrosine kinase cessation attempt, according to EURO-SKI criteria, was 31%. Our findings show that in a ‘real-world’ setting the long-term outcome of patients treated with tyrosine kinase inhibitors is excellent and the conditions for an attempt to stop tyrosine kinase inhibitor therapy are met by a third of the patients.

Efficacy of ibrutinib in a patient with transformed lymphoplasmacytic lymphoma and central nervous system involvement

Laura S. Hiemcke-Jiwa, Roos J. Leguit, Joyce H. Radersma-van Loon, Peter E. Westerweel, Johannes J. M. Rood, Jeanette K. Doorduijn, Manon M. H. Huibers and Monique C. Minnema Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands; Department of Internal Medicine, Albert Schweitzer hospital Dordrecht, Dordrecht, The Netherlands; Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht University, Faculty of Science, Utrecht, The Netherlands; Department of Hematology, Erasmus Cancer Institute Rotterdam, Rotterdam, The Netherlands; Department of Hematology, University Medical Center Utrecht Cancer Center, Utrecht, The Netherlands

Impact of hospital experience on the quality of tyrosine kinase inhibitor response monitoring and consequence for chronic myeloid leukemia patient survival

The importance of adequate response monitoring during the treatment of chronic myeloid leukemia (CML) with tyrosine kinase inhibitors (TKIs) and testing for BCR-ABL1 kinase domain (KD) mutations in case of TKI failure is generally acknowledged and clearly outlined in guidelines and recommendations

Rituximab addition to chemotherapy in real world patients with chronic lymphocytic leukemia: effective in first line but indication of lack of efficacy in subsequent lines of therapy

Lina van der Straten , Avinash G. Dinmohamed , Peter E. Westerweel, Anton W. Langerak, Jurgen Riedl, Jeanette K. Doorduijn, Arnon P. Kater and Mark-David Levin Department of Internal Medicine, Albert Schweitzer Hospital, Dordrecht, The Netherlands; Department of Research, Netherlands Comprehensive Cancer Organisation (IKNL), Utrecht, The Netherlands; Department of Public Health, Erasmus University Medical Centre, Rotterdam, The Netherlands; Department of Hematology, Erasmus MC Cancer Institute, Rotterdam, The Netherlands; Department of Immunology, Erasmus University Medical Centre, Rotterdam, The Netherlands; Department of Clinical Chemistry, Result laboratories, Albert Schweitzer Hospital, Dordrecht, The Netherland; Department of Hematology, Academic Medical Centre, Amsterdam, the Netherlands

Omitting cytogenetic assessment from routine treatment response monitoring in chronic myeloid leukemia is safe

The monitoring of response in chronic myeloid leukemia (CML) is of great importance to identify patients failing their treatment in order to adjust TKI choice and thereby prevent progression to advanced stage disease. Cytogenetic monitoring has a lower sensitivity, is expensive, and requires invasive bone marrow sampling. Nevertheless, chronic myeloid leukemia guidelines continue to recommend performing routine cytogenetic response assessments, even when adequate molecular diagnostics are available.

Considerations for treatment-free remission in patients with chronic myeloid leukemia: a joint patient-physician perspective

&NA; Treatment‐free remission (TFR) after discontinuation of tyrosine kinase inhibitor therapy is now an emerging treatment goal for patients with chronic myeloid leukemia, who have achieved a deep and stable response to treatment. Although guidance is now available, patients’ questions regarding this progressive concept have yet to be addressed. The overall aim of this European Steering Group is a patient‐centered approach that educates patients on their treatment options, including TFR, facilitates better patient–physician relationships, and meets patients’ emotional and psychological needs. The present report outlines 5 key topic areas on discontinuing tyrosine kinase therapy and the implications of TFR for patient–physician consideration: what TFR is; when TFR is appropriate; which patients might and might not be eligible for TFR; and patients’ considerations for discontinuing therapy, such as tyrosine kinase withdrawal syndrome, potential psychological implications, molecular recurrence, and repeat treatment. This Steering Group advocates that patients with chronic myeloid leukemia should have access to high‐quality, frequent molecular monitoring and be treated in a specialist center with appropriate medical and psychological support. As patient concerns with attempting TFR become forefront in patient–physician discussions, a greater number of eligible patients might be willing to discontinue therapy.

Telomere shortening correlates with leukemic stem cell burden at diagnosis of chronic myeloid leukemia

Telomere length (TL) in peripheral blood (PB) cells of patients with chronic myeloid leukemia (CML) has been shown to correlate with disease stage, prognostic scores, response to therapy, and disease progression. However, due to considerable genetic interindividual variability, TL varies substantially between individuals, limiting its use as a robust prognostic marker in individual patients. Here, we compared TL of BCR-ABL-, nonleukemic CD34+CD38- hematopoietic stem cells (HSC) in the bone marrow of CML patients at diagnosis to their individual BCR-ABL+ leukemic stem cell (LSC) counterparts. We observed significantly accelerated telomere shortening in LSC compared with nonleukemic HSC. Interestingly, the degree of LSC telomere shortening was found to correlate significantly with the leukemic clone size. To validate the diagnostic value of nonleukemic cells as internal controls and to rule out effects of tyrosine kinase inhibitor (TKI) treatment on these nontarget cells, we prospectively assessed TL in 134 PB samples collected in deep molecular remission after TKI treatment within the EURO-SKI study (NCT01596114). Here, no significant telomere shortening was observed in granulocytes compared with an age-adjusted control cohort. In conclusion, this study provides proof of principle for accelerated telomere shortening in LSC as opposed to HSC in CML patients at diagnosis. The fact that the degree of telomere shortening correlates with leukemic clones size supports the use of TL in leukemic cells as a prognostic parameter pending prospective validation. TL in nonleukemic myeloid cells seems unaffected even by long-term TKI treatment arguing against a reduction of telomere-mediated replicative reserve in normal hematopoiesis under TKI treatment.