IFN-α with dasatinib broadens the immune repertoire in patients with chronic-phase chronic myeloid leukemia.

In chronic myeloid leukemia (CML), combination therapies with tyrosine kinase inhibitors (TKIs) aim to improve the achievement of deep molecular remission that would allow therapy discontinuation. IFN-α is one promising candidate, as it has long-lasting effects on both malignant and immune cells. In connection with a multicenter clinical trial combining dasatinib with IFN-α in 40 patients with chronic-phase CML (NordCML007, NCT01725204), we performed immune monitoring with single-cell RNA and T cell receptor (TCR) sequencing (n = 4, 12 samples), bulk TCRß sequencing (n = 13, 26 samples), flow cytometry (n = 40, 106 samples), cytokine analyses (n = 17, 80 samples), and ex vivo functional studies (n = 39, 80 samples). Dasatinib drove the immune repertoire toward terminally differentiated NK and CD8+ T cells with dampened functional capabilities. Patients with dasatinib-associated pleural effusions had increased numbers of CD8+ recently activated effector memory T (Temra) cells. In vitro, dasatinib prevented CD3-induced cell death by blocking TCR signaling. The addition of IFN-α reversed the terminally differentiated phenotypes and increased the number of costimulatory intercellular interactions and the number of unique putative epitope-specific TCR clusters. In vitro IFN-α had costimulatory effects on TCR signaling. Our work supports the combination of IFN-α with TKI therapy, as IFN-α broadens the immune repertoire and restores immunological function.

Long-term tolerability and efficacy after initial PegIFN-α addition to dasatinib in CML-CP: Five-year follow-up of the NordCML007 study.

OBJECTIVES: Treatment-free remission (TFR) has emerged as a treatment goal in chronic myeloid leukemia in the chronic phase (CML-CP). Attempts to increase proportion of patients achieving TFR include combination of tyrosine kinase inhibitors (TKI) and other drugs. Interferon-α in addition to TKI has shown promising efficacy but with dose-dependent toxicity and discontinuations. NordCML007 was initiated to study the efficacy and safety of low dose pegylated IFN-α (PegIFN-α) in combination with dasatinib (DAS) in CML-CP. METHODS: Forty patients with newly diagnosed CML-CP were given DAS upfront. After month 3 (M3) 15 µg/wk of PegIFN-α was added and increased to 25 µg/wk from M7 until M15. DAS treatment was continued and adverse events and BCR-ABL1 qRT-PCR values were reported yearly after M24. Results from M1 to M18 have previously been published, and here we present long-term data. RESULTS: After 5 years of follow-up, there were no suspected unexpected serious adverse reactions, no increase in serosal effusions, no disease progressions and no CML-related deaths. Rates of MR3.0 (MMR), MR4.0 and MR4.5 were 84.6%, 64.1% and 51.3% respectively at M60, and 95% of patients reached MMR at some point during the study. CONCLUSION: Initial addition of PegIFN-α to DAS shows good long-term efficacy without increased toxicity.

Successful tyrosine kinase inhibitor discontinuation outside clinical trials - data from the population-based Swedish chronic myeloid leukaemia registry.

Clinical trials show that tyrosine kinase inhibitor (TKI) treatment can be discontinued in selected patients with chronic myeloid leukaemia (CML). Although updated CML guidelines support such procedure in clinical routine, data on TKI stopping outside clinical trials are limited. In this retrospective study utilising the Swedish CML registry, we examined TKI discontinuation in a population-based setting. Out of 584 patients diagnosed with chronic-phase CML (CML-CP) in 2007-2012, 548 had evaluable information on TKI discontinuation. With a median follow-up of nine years from diagnosis, 128 (23%) discontinued TKI therapy (≥1 month) due to achieving a DMR (deep molecular response) and 107 (20%) due to other causes (adverse events, allogeneic stem cell transplant, pregnancy, etc). Among those stopping in DMR, 49% re-initiated TKI treatment (median time to restart 4·8 months). In all, 38 patients stopped TKI within a clinical study and 90 outside a study. After 24 months 41·1% of patients discontinuing outside a study had re-initiated TKI treatment. TKI treatment duration pre-stop was longer and proportion treated with second-generation TKI slightly higher outside studies, conceivably affecting the clinical outcome. In summary we show that TKI discontinuation in CML in clinical practice is common and feasible and may be just as successful as when performed within a clinical trial.

Introducing patient-reported outcome in the acute leukemia quality registries in Sweden.

OBJECTIVES: The use of patient-reported outcome (PRO) measured outside clinical trials is not well defined. We report the first analysis of the prospective PRO study within the Swedish acute myeloid leukemia (AML) and the acute lymphoblastic leukemia (ALL) registries. METHODS: PRO was requested 6 months after diagnosis. The EORTC Quality of life Questionnaire Core 30-item, the Patient Health Questionnaire-8 (PHQ-8), and questions from a Swedish National Cancer Questionnaire were used. RESULTS: An invitation letter was sent to 398 patients; 255 (64%) responded, 60% web-based, and 40% on paper. The ALL cohort had lower physical, role and social functioning, higher symptom burden, and more financial difficulties compared to the AML cohort. A PHQ-8 score ≥ 10p, which indicates depression, was reported in 18% of the patients; 33% of these patients reported being prescribed antidepressants. The patients' overall experience of care was satisfying, but more psychological and practical support was desired. There was no difference in survival between patients who reported their PRO and those who did not. Follow-up at 2 and 4 years is ongoing. CONCLUSIONS: PRO collected in a registry-based setting is feasible, but the selection of time points and questionnaires are delicate in a diverse patient population.

Survival in adult acute lymphoblastic leukaemia (ALL): A report from the Swedish ALL Registry.

OBJECTIVES: As new, effective therapies emerge for acute lymphoblastic leukaemia (ALL), the results of clinical trials need to relate to standard of care. METHODS: We used the population-based Swedish ALL Registry to evaluate characteristics, treatment and long-term outcome in 933 patients with diagnosis between 1997 and 2015. RESULTS: The median age was 53 years. The frequency of Philadelphia (Ph)-positive leukaemia was 34% of examined B-ALL with a peak incidence at 50-59 years. Five-year overall survival (OS) improved between 1997-2006 and 2007-2015; in patients 18-45 years from 50% (95% CI 43-57) to 65% (95% CI 58-72), 46-65 years from 25% (95% CI 18-32) to 46% (95% CI 37-55) and >65 years from 7% (95% CI 2.6-11) to 11% (95% CI 5.9-16) (P < 0.05). Men with Ph-neg B-ALL 46-65 years had inferior OS compared with women (P < 0.01). Standardised mortality ratio was 5.7 (95% CI 5.0-6.3) for patients who survived 5 years from diagnosis. In multivariable analysis, Ph-positive disease was not associated with impaired prognosis but with lower risk of death in 2007-2015. CONCLUSIONS: In a population-based cohort, OS has improved in adult ALL, especially for Ph-positive disease but for middle-aged men with Ph-negative B-ALL outcome was poor. Cure without late toxicity or relapse is still desired.

Allogeneic stem cell transplantation for chronic myeloid leukemia in the TKI era: population-based data from the Swedish CML registry.

Two decades after the introduction of tyrosine kinase inhibitors (TKI), a sizeable portion of patients with chronic myeloid leukemia (CML) in chronic phase (CP) still undergo allogeneic stem cell transplantation (allo-HSCT). We investigated the indications for allo-HSCT, clinical outcome, management of relapse, and post-transplant TKI treatment in a population-based setting using the Swedish CML registry. Of 118 CML patients transplanted between 2002 and 2017, 56 (47.4%) received allo-HSCT in first CP, among whom TKI resistance was the most common transplant indication (62.5%). For patients diagnosed with CML in CP at <65 years of age, the cumulative probability of undergoing allo-HSCT within 5 years was 9.7%. Overall 5-year survival was 96.2%, 70.1% and 36.9% when transplanted in first CP, second or later CP, and in accelerated phase or blast crisis, respectively. Risk factors for relapse were EBMT score >2 and reduced intensity conditioning, and for death, CP > 2 at time point of allo-HSCT only. Non-relapse mortality for patients transplanted in CP was 11.6%. Our data indicate that allo-HSCT still constitutes a reasonable therapeutic option for patients with CML in first CP, especially those resistant to TKI treatment, providing high long-term survival and low non-relapse mortality.

Advanced phase chronic myeloid leukaemia (CML) in the tyrosine kinase inhibitor era - a report from the Swedish CML register.

OBJECTIVES: The primary goal in management of chronic phase (CP) chronic myeloid leukaemia (CML) is to prevent disease progression to accelerated phase (AP) or blast crisis (BC). We have evaluated progression rates in a decentralised healthcare setting and characterised patients progressing to AP/BC on TKI treatment. METHODS: Using data from the Swedish CML register, we identified CP-CML patients diagnosed 2007-2011 who progressed to AP/BC within 2 yrs from diagnosis (n = 18) as well as patients diagnosed in advanced phase during 2007-2012 (n = 36) from a total of 544 newly diagnosed CML cases. We evaluated baseline characteristics, progression rates, outcome and adherence to guidelines for monitoring and treatment. RESULTS: The cumulative progression rate at 2 yrs was 4.3%. All 18 progression cases had been treated with imatinib, and six progressed within 6 months. High-risk EUTOS score was associated to a higher risk of progression. Insufficient cytogenetic and/or molecular monitoring was found in 33%. Median survival after transformation during TKI treatment was 1.4 yrs. In those presenting with BC and AP, median survival was 1.6 yrs and not reached, respectively. CONCLUSION: In this population-based setting, progression rates appear comparable to that reported from clinical trials, with similar dismal patient outcome. Improved adherence to CML guidelines may minimise the risk of disease progression.

Young woman with mild bone marrow dysplasia, GATA2 and ASXL1 mutation treated with allogeneic hematopoietic stem cell transplantation.

Heterozygous mutations in GATA2 underlie different syndromes, previously described as monocytopenia and mycobacterial avium complex infection (MonoMAC); dendritic cell, monocytes, B- and NK lymphocytes deficiency (DCML); lymphedema, deafness and myelodysplasia (Emberger syndrome) and familiar myelodysplastic syndrome/acute myeloid leukemia (MDS / AML). Onset and severity of clinical symptoms vary and preceding cytopenias are not always present. We describe a case of symptomatic DCML deficiency and rather discrete bone marrow findings due to GATA2 mutation. Exome sequencing revealed a somatic ASXL1 mutation and the patient underwent allogeneic stem cell transplantation successfully.

FLT3 ligand and not TSLP is the key regulator of IL-7-independent B-1 and B-2 B lymphopoiesis.

Phenotypically and functionally distinct progenitors and developmental pathways have been proposed to exist for fetally derived B-1 and conventional B-2 cells. Although IL-7 appears to be the primary cytokine regulator of fetal and adult B lymphopoiesis in mice, considerable fetal B lymphopoiesis and postnatal B cells are sustained in the absence of IL-7; in humans, B-cell generation is suggested to be largely IL-7-independent, as severe combined immune-deficient patients with IL-7 deficiency appear to have normal B-cell numbers. However, the role of other cytokines in IL-7-independent B lymphopoiesis remains to be established. Although thymic stromal lymphopoietin (TSLP) has been proposed to be the main factor driving IL-7-independent B lymphopoiesis and to distinguish fetal from adult B-cell progenitor development in mice, recent studies failed to support a primary role of TSLP in IL-7-independent fetal B-cell development. However, the role of TSLP in IL-7-independent adult B lymphopoiesis and in particular in regulation of B-1 cells remains to be established. Here we demonstrate that, rather than TSLP, IL-7 and FLT3 ligand are combined responsible for all B-cell generation in mice, including recently identified B-1-specified cell progenitors. Thus, the same IL-7- and FLT3 ligand-mediated signal-ing regulates alternative pathways of fetal and adult B-1 and B-2 lymphopoiesis.

Permissive roles of hematopoietin and cytokine tyrosine kinase receptors in early T-cell development.

Although several cytokines have been demonstrated to be critical regulators of development of multiple blood cell lineages, it remains disputed to what degree they act through instructive or permissive mechanisms. Signaling through the FMS-like tyrosine kinase 3 (FLT3) receptor and the hematopoietin IL-7 receptor alpha (IL-7Ralpha) has been demonstrated to be of critical importance for sustained thymopoiesis. Signaling triggered by IL-7 and thymic stromal lymphopoietin (TSLP) is dependent on IL-7Ralpha, and both ligands have been implicated in T-cell development. However, we demonstrate that, whereas thymopoiesis is abolished in adult mice doubly deficient in IL-7 and FLT3 ligand (FLT3L), TSLP does not play a key role in IL-7-independent or FLT3L-independent T lymphopoiesis. Furthermore, whereas previous studies implicated that the role of other cytokine tyrosine kinase receptors in T lymphopoiesis might not involve permissive actions, we demonstrate that ectopic expression of BCL2 is sufficient not only to partially correct the T-cell phenotype of Flt3l(-/-) mice but also to rescue the virtually complete loss of all discernable stages of early T lymphopoiesis in Flt3l(-/-)Il7r(-/-) mice. These findings implicate a permissive role of cytokine receptors of the hematopoietin and tyrosine kinase families in early T lymphopoiesis.

Interferon alpha (IFN) treatment of bone marrow stroma inhibits haematopoesis.

Prolonged pre-transplant IFN administration in patients with chronic myeloid leukaemia has been associated with an increased risk of fatal transplant-related complications and an inferior outcome after allogeneic bone marrow transplantation. Using a two-stage long-term bone marrow culture as an in vitro model we were able to show a negative effect of higher doses of IFN pre-treatment of bone marrow stroma on haematopoesis. This correlated with a decline in the number of monocytes-macrophages. While monocytes-macrophages itself produce cytokines, a vicious circle may lead to an ineffective function of the microenvironment resulting in ineffective haematopoieses and increased transplant-related complications.