Presenting features and treatment outcome of acute promyelocytic leukemia arising after multiple sclerosis

Immunological Aspects of Approved MS Therapeutics

Multiple sclerosis (MS) is the most common neurological immune-mediated disease leading to disability in young adults. The outcome of the disease is unpredictable, and over time, neurological disabilities accumulate. Interferon beta-1b was the first drug to be approved in the 1990s for relapsing-remitting MS to modulate the course of the disease. Over the past two decades, the treatment landscape has changed tremendously. Currently, more than a dozen drugs representing 1 substances with different mechanisms of action have been approved (interferon beta preparations, glatiramer acetate, fingolimod, siponimod, mitoxantrone, teriflunomide, dimethyl fumarate, cladribine, alemtuzumab, ocrelizumab, and natalizumab). Ocrelizumab was the first medication to be approved for primary progressive MS. The objective of this review is to present the modes of action of these drugs and their effects on the immunopathogenesis of MS. Each agent's clinical development and potential side effects are discussed.

Myeloid disorders after autoimmune disease

Autoimmune diseases (ADs) are associated with an increased risk not only of lymphoproliferative disorders but also of myeloid malignancies. The excess risk of myelodysplastic syndromes and/or acute myeloid leukemia is observed across several AD types, including systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disorders, multiple sclerosis, among others. The risk of developing myeloid neoplasms (MNs) is dependent on several variables, including the specific AD type, chronicity and severity of the AD, type and duration of exposure of disease modifying anti-rheumatic drugs or cytotoxics/immunosuppressives, and genetic predisposition risk. Putative triggering factors linking AD to elevated MN risk include AD-directed medications, shared genetic susceptibilities between the two disease entities, and chronic immune stimulation or bone marrow infiltration by the AD. Molecular mechanisms underpinning leukemogenesis remain largely speculative and warrant further investigation. Leukemias arising in patients with AD are not always 'therapy-related' in that MNs may develop in certain AD subtypes even among patients with no prior therapy exposure. Only a few studies have attempted to determine factors associated with MN development in AD but failed to demonstrate consistent characteristic clinical or paraclinical features. These reports have failed to demonstrate a clear correlation between individual agent exposure and subsequent leukemia development due to the low rates of therapy exposure compounded by the rarity of MN occurrence. Notwithstanding, the leukemogenic potential is best documented with agents such as azathioprine, cyclophosphamide, and mitoxantrone; this risk of MN development does not appear to be shared by biologic approaches such as anti-tumor necrosis factors-alpha inhibitors. In this article, we discuss plausible biologic mechanisms underlying MN pathogenesis in AD and review the data available on the development of MNs in patients with AD.

Therapy-related acute leukaemia with mitoxantrone: four years on, what is the risk and can it be limited?

Therapy-related acute leukaemia (TRAL) is a significant concern, when considering treatment with mitoxantrone for multiple sclerosis (MS). We re-evaluated the literature, identifying all case reports and series of > 50 patients reporting TRAL cases in MS. TRAL was diagnosed in 0.73% of the 12,896 patients identified. Median onset was 22 months following treatment. We calculated a number needed to harm of 137.5 exposed patients, significantly higher than our 2008 analysis. We found that 82.8% of patients were exposed to > 60 mg/m(2) with a relative risk of 1.85 (p = 0.018) compared to < 60 mg/m(2), strongly suggesting a relationship to dose. MS treatment regimens which limit the mitoxantrone dose to < 60 mg/m(2) reduce the risk of TRAL.

A focused review of hematopoietic neoplasms occurring in the therapy-related setting

Hematological neoplasms developed in patients with a history of cytotoxic therapies comprise a group of diseases with a poor clinical outcome, and collectively categorized as "therapy-related myeloid neoplasms" (t-MN) in the 2008 World Health Organization (WHO) Classification. In recent years, numerous publications have emerged, and these studies have greatly expanded the scope of our understanding in this field. We here focused our review on several selected areas including secondary malignancies occurring in patients with autoimmune diseases; radiation therapy alone as a causative agent; the similarity and differences between therapy-related myelodysplastic syndromes (t-MDS) and acute myeloid leukemia (t-AML); clinical behavior and treatment outcome of t-AML patients with favorable cytogenetics; the incidence and clinical features of myelodysplastic/myeloproliferative neoplasms, as well as acute lymphoblastic leukemia and myeloproliferative neoplasms in patients with prior cytotoxic exposure. These recent studies have shown that therapy-related hematopoietic neoplasms are heterogeneous, and may manifest in various forms, more complex than we have recognized previously. Cytogenetic abnormalities and underlying mutations are likely to be the major factors dictating prognosis.

The current role of mitoxantrone in the treatment of multiple sclerosis

Mitoxantrone is an immunosuppressive drug approved for aggressive relapsing and progressive multiple sclerosis. In recent years, its use has decreased due to the risk of severe adverse events and the introduction of novel therapies, such as natalizumab or fingolimod. Mitoxantrone is effective in reducing inflammatory activity by decreasing the number of relapses and MRI lesions and simultaneously decreasing the worsening of disability. Apart from its role as a second/third-line therapy, some studies suggest its use as an induction therapy. However, mitoxantrone use is limited because of its potential risk of severe adverse events, such as cardiotoxicity and the induction of therapy-related acute leukemia. Genetic markers are on evaluation to predict side effects and therapeutic efficacy, which is consistent with the direction of personalized treatment. Considering its efficacy and the potential risks, mitoxantrone use is limited to active patients after a careful, individualized evaluation of the risk/benefit balance.

Management of disease-modifying treatments in neurological autoimmune diseases of the central nervous system

The therapeutic armamentarium for autoimmune diseases of the central nervous system, specifically multiple sclerosis and neuromyelitis optica, is steadily increasing, with a large spectrum of immunomodulatory and immunosuppressive agents targeting different mechanisms of the immune system. However, increasingly efficacious treatment options also entail higher potential for severe adverse drug reactions. Especially in cases failing first-line treatment, thorough evaluation of the risk-benefit profile of treatment alternatives is necessary. This argues for the need of algorithms to identify patients more likely to benefit from a specific treatment. Moreover, paradigms to stratify the risk for severe adverse drug reactions need to be established. In addition to clinical/paraclinical measures, biomarkers may aid in individualized risk-benefit assessment. A recent example is the routine testing for anti-John Cunningham virus antibodies in natalizumab-treated multiple sclerosis patients to assess the risk for the development of progressive multi-focal leucoencephalopathy. Refined algorithms for individualized risk assessment may also facilitate early initiation of induction treatment schemes in patient groups with high disease activity rather than classical escalation concepts. In this review, we will discuss approaches for individiualized risk-benefit assessment both for newly introduced agents as well as medications with established side-effect profiles. In addition to clinical parameters, we will also focus on biomarkers that may assist in patient selection.

Clinical and pathologic features of secondary acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a relatively common form of acute myeloid leukemia (AML) that has an excellent prognosis. In contrast, secondary acute myeloid leukemias, including therapy-related AML and AML with myelodysplasia-related changes, have a relatively poor prognosis. We identified 9 cases of APL at our institution in which there was a history of chemotherapy, radiotherapy, chronic immunosuppression, or antecedent myelodysplastic syndrome. The clinical and pathologic findings in these cases of secondary APL were compared with the clinical and pathologic findings in cases of de novo APL. We found that secondary and de novo APL had abnormal promyelocytes with similar morphologic and immunophenotypic features, comparable cytogenetic findings, comparable rates of FMS-like tyrosine kinase mutations, and similar rates of recurrent disease and death. These data suggest that secondary APL is similar to de novo APL and, thus, should be considered distinct from other secondary acute myeloid neoplasms.

Therapy-related acute leukemia in two patients with multiple sclerosis treated with Mitoxantrone

Two cases of therapy-related acute leukemia (TRAL) after the use of Mitoxantrone for the treatment of secondary progressive multiple sclerosis (MS) are reported. They were extracted from the group of 42 consecutive patients with TRAL diagnosed and treated in single centre between 2000-2010. They were the only two with MS and the only two treated with Mitoxantrone. The first patient was a 43-year-old male with a previous history of MS of 15-year-duration, who developed acute promyelocytic leukemia 9 months following Mitoxantrone therapy (cumulative dose 120 mg). The second patient was a 55-year-old female suffering from MS for 16 years, who developed acute mixed-phenotype leukemia, T/myeloid type, with 46,XX,del(7)(p13)[12]/47,XX,idem,+3/[6]/46,XX[2], 15 months after completion of Mitoxantrone therapy (cumulative dose 100mg). Acute mixed-phenotype leukemia, T/myeloid type is for the first time described in the context of prior Mitoxantrone therapy. Although the incidence of TRAL in relation to Mitoxantrone pretreatment is rare, we should be vigilant for the prompt identification of this adverse event.

Acute myeloid leukemia developing in patients with autoimmune diseases

Therapy-related acute myeloid leukemia is an unfortunate complication of cancer treatment, particularly for patients with highly curable primary malignancies and favorable life expectancy. The risk of developing therapy-related acute myeloid leukemia also applies to patients with non-malignant conditions, such as autoimmune diseases treated with cytotoxic and/or immunosuppressive agents. There is considerable evidence to suggest that there is an increased occurrence of hematologic malignancies in patients with autoimmune diseases compared to the general population, with a further increase in risk after exposure to cytotoxic therapies. Unfortunately, studies have failed to reveal a clear correlation between leukemia development and exposure to individual agents used for the treatment of autoimmune diseases. Given the dismal outcome of secondary acute myeloid leukemia and the wide range of available agents for treatment of autoimmune diseases, an increased awareness of this risk and further investigation into the pathogenetic mechanisms of acute leukemia in autoimmune disease patients are warranted. This article will review the data available on the development of acute myeloid leukemia in patients with autoimmune diseases. Possible leukemogeneic mechanisms in these patients, as well as evidence supporting the association of their primary immunosuppressive status and their exposure to specific therapies, will also be reviewed. This review also supports the idea that it may be misleading to label leukemias that develop in patients with autoimmune diseases who are exposed to cytotoxic agents as 'therapy-related leukemias'. A better understanding of the molecular defects in autoimmune disease patients who develop acute leukemia will lead to a better understanding of the association between these two diseases entities.

Acute promyelocytic leukemia: an experience on 95 greek patients treated in the all-trans-retinoic Acid era

Acute promyelocytic leukemia (APL) is highly curable with the combination of all-transretinoic acid (ATRA) and anthracycline based chemotherapy, but the percentage of early deaths remains high. In the present study, we report the clinical, immunophenotypic, cytogenetic and molecular characteristics and outcome of APL patients diagnosed and treated in various Hospitals of Greece and Cyprus.We describe the data of ninety-five APL patients who were diagnosed during the last 15 years. Seven (7.4%) newly diagnosed APL patients died due to intracranial hemorrhage within 72 hours of presentation. All but two patients were induced with ATRA alone or ATRA plus chemotherapy. The early death rate was 14.9%. After induction all 80 evaluable patients achieved complete hematologic remission. The cumulative incidence of relapse was 18.3%. Eight of the ten relapsed patients were successfully salvaged, while both patients with molecularly resistant disease died during salvage treatment. Overall survival (OS) at 5 years was 78.4% and disease free survival (DFS) 73.6%. In multivariate analysis of OS age over 60 years, DIC at diagnosis and marginally major hemorrhage at presentation were identified as adverse prognostic factors. In the subgroup of patients with available data on FLT3 mutation status (49 out of 94), ITD positivity also remained as an independent prognostic factor in the final model of OS, together with major hemorrhage and marginally high Sanz score. We found a close correlation between the CD2 expression and the development of the differentiation syndrome (DS). In conclusion, the main problem in managing patients with APL is still the high early death rate.

Therapy-related acute promyelocytic leukemia: observations relating to APL pathogenesis and therapy

Therapy-related acute promyelocytic leukemia (t-APL) is a well-recognized form of APL for which the underlying etiology has been well characterized. The pathogenesis of de novo (dn-APL) remains unknown; but epidemiologic studies have consistently identified increased body mass index (BMI), younger age, and ethnicity as possible risk factors. We analyzed demographics, clinical features, and treatment responses in a contemporary series of 64 patients treated with all-trans-retinoic acid and anthracycline-based therapy to assess for differences in these two etiologically distinct patient groups. Compared with patients with t-APL (n = 11), those with dn-APL (n = 53) had a greater median BMI (31.33 vs. 28.48), incidence of obesity (60.4% vs. 27.3%) (P = 0.04), and history of hyperlipidemia (45.3% vs. 18.2%) (P = 0.01). Fewer t-APL than dn-APL patients achieved complete remission at 63.6% vs. 92.5% respectively (P = 0.008). This was the result of a higher induction mortality rate of 36.4% vs. 7.5% respectively (P = 0.008). No cases of leukemic resistance were seen in either group. Overall survival (OS) was inferior in t-APL compared with dn-APL at 51% vs. 84%, respectively (P < 0.005), primarily as a result of higher induction mortality. Relapse occurred in nine patients (16.1%) overall, but no relapses occurred in the t-APL cohort. Our observations provide further support for the hypothesis that abnormalities in lipid homeostasis may in some way be of pathogenic importance in dn-APL. Therapy-related APL is sensitive to standard therapy with no cases of resistance or relapse seen. The inferior OS of the t-APL was due to induction mortality, possibly reflecting prior therapy.