Pregnancy: part of life in chronic myelogenous leukemia

SOHO State of the Art Updates and Next Questions: Chronic Myeloid Leukemia and Pregnancy: "Per Aspera Ad Astra"

Chronic myeloid leukemia (CML) has evolved from an invariably fatal disease to a chronic disorder that can be treated with targeted drugs and allows survival expectations approaching age-matched controls. Thus, pregnancy and conception in CML should not be precluded anymore; however, to ensure the well-being of both the mother and the developing fetus careful planning and management are required. Tyrosine Kinase Inhibitors (TKIs) are not genotoxic or carcinogenic but can pose a risk to the developing fetus, due to their teratogenic potential. The risk depends on the TKI and the stage of fetal development during exposure. Teratogenic risk is high in the first trimester of pregnancy when the baby's organs and structures are forming (5-12 weeks). If a female patient is on therapy it is advisable to stop therapy at the first positive pregnancy test (3-5 weeks) to maximize the length of treatment-free, and ideally to not treat until delivery. If needed, the medication plan during pregnancy may be adjusted. Interferons can be used at any time, imatinib and nilotinib have a reduced placental crossing and could be carefully used after 16 weeks, whereas dasatinib crosses the placenta and can induce problems throughout the whole gestation. Management of pregnancy in CML is complex. This manuscript is an update of the state of the art allowing healthcare providers to be informed of the different situations that can occur and their governance.

Chronic myeloid leukemia diagnosed in pregnancy: management and outcome of 87 patients reported to the European LeukemiaNet international registry

The management of chronic myeloid leukemia (CML) diagnosed during pregnancy is a rare and challenging situation. We report the treatment and outcome of 87 cases diagnosed in chronic phase from 2001-2022 derived from the largest international observational registry, supported by the European LeukemiaNet (ELN), of 400 pregnancies in 299 CML women. Normal childbirth occurred in 76% without an increased rate of birth abnormalities or life-threatening events, including in patients untreated or treated with interferon-α and/or imatinib in 2nd-3rd trimester. The low birth weight rate of 12% was comparable to that seen in the normal population. Elective and spontaneous abortions occurred in 21% and 3%, respectively. The complete hematologic response rate before labor was 95% with imatinib and 47% with interferon only. No disease progression during pregnancy was observed, 28% of the patients switched their therapy at varying times after delivery. Treatment options balance the efficacy and safety for mother and infant: interferon-α can commence in the 1st trimester and continued throughout in cases of good disease control and tolerability. Because of limited placental crossing, selected tyrosine kinase inhibitors (imatinib and nilotinib) seem to be safe and effective options in 2nd and 3rd trimester while hydroxycarbamide offers few benefits.

Male Fertility and Fatherhood in Chronic Myeloid Leukemia: Current Understanding and Future Perspectives

Chronic myeloid leukemia (CML), while traditionally a disease of the elderly, has recently risen in incidence among younger patients. Hence, fertility concerns have emerged considering the disease process and treatments, especially with the current scarce and conflicting recommendations. This review explores the impact of CML treatments including the first-line tyrosine kinase inhibitors (TKIs) and other treatments on male fertility in chronic myeloid leukemia (CML) patients. The aim of this review was to compile the available evidence on male fertility to ultimately tailor treatment plans for male CML patients for whom fertility and future chances for conception pose a concern. The data available on the conventional and newer TKIs to address fertility concerns were reviewed, particularly the potential long- and short-term effects. Also, the possible side effects on subsequent generations were a crucial focus point of this review to reach a more comprehensive CML management approach. We found and compared the evidence on TKIs approved to treat CML. We also reported the effects of hydroxyurea, interferon, and transplantation, which are considered second-line treatments. Our findings suggest that these drugs might have an undiscovered effect on fertility. More research with larger sample sizes and longer follow-up periods is essential to solidify our understanding of these effects.

Imatinib reduces the fertility of male mice by penetrating the blood-testis barrier and inducing spermatogonia apoptosis

Imatinib, the first generation of tyrosine kinase inhibitor, is used to treat and improve the prognosis of chronic myelogenous leukemia (CML). Clinical data suggest that imatinib could cross the blood-testis barrier and reduces the fertility of patients with CML-chronic phase. However, its exact molecular mechanism has not been fully elucidated. In this study, adult male Kunming mice were treated with different doses of imatinib for 8 weeks. The fertility was evaluated, and the sex hormone levels in the blood were detected by enzyme-linked immunosorbent assay. Histological changes were detected by hematoxylin and eosin staining. The concentration of imatinib in semen and blood was detected by liquid chromatography-mass spectrometry. The ultrastructure of blood-testis barrier and apoptotic bodies were observed by transmission electron microscope. The expression of blood-testis barrier function-regulating protein, Mfsd2a, and apoptosis-associated proteins in testis tissue was detected by immunohistochemistry and Western blot. The results indicated that the fertility of male mice was significantly decreased in a dose-dependent manner after imatinib treatment. Certain hormones in the serum were increased in imatinib treatment groups. Sperm morphology and testicular tissue showed various changes after imatinib treatment. The blood-testis barrier was destroyed and the concentration of imatinib in semen was similar to that in blood after imatinib treatment. Apoptosis was significantly increased in testis tissue after imatinib treatment. Collectively, these results suggest that imatinib can alter blood-testis barrier function, induce apoptosis of spermatogonia, and adversely affect fertility by reducing the number of spermatozoa, decreasing sperm motility and increasing the deformity rate.

What factors determine the pregnancy outcome in patients with essential thrombocythemia?

Objectives: Treatment of essential thrombocythemia (ET) is particularly challenging in pregnancy due to the increased risk of thromboembolic complications. Therefore, the use of antithrombotic regimens are recommended in pregnant women with ET.Methods: The study included 52 pregnancies in 27 patients diagnosed with ET, who were treated in Department of Haematology. The influence of anticoagulant, antiplatelet and cytoreductive therapy on the course and outcome of pregnancy was analysed. This study also examined if there was any correlation between molecular and clinical features such as mutational profile, blood count, presence of acquired von Willebrand syndrome (AvWS), the International Prognostic Score for Essential Thrombocythemia (IPSET) risk group and the IPSET-thrombosis risk group and pregnancy outcome.Results: Study participants who received antithrombotic therapy were significantly more likely to give birth to a healthy child. The best outcomes were observed in patients who received low dose acetylsalicylic acid (ASA) together with low-molecular-weight heparin (LMWH). There was a statistically significant correlation between classification to the high-risk group according to the IPSET-thrombosis score and incidence of miscarriage. Cytoreductive treatment with interferon-α2, as well as the presence of AvWS did not increase the likelihood of pregnancy loss. Blood counts and presence of specific gene mutations profile were also not found to be significant determinants of pregnancy outcome.Conclusion: To our best knowledge, this is the first clinical study investigating the correlation between risk group (according to IPSET and IPSET-thrombosis) and pregnancy outcome in women with ET.

CML Chapter

The discovery of the tyrosine kinase inhibitor (TKI) imatinib in the early 2000's revolutionized the treatment and prognosis of patients with chronic myeloid leukemia (CML) [Hochhaus et al. in N Engl J Med 376:917-927, 2017]. The treatment of patients with CML has changed dramatically since the approval of imatinib and other TKIs. Before the TKI era, newly diagnosed patients would undergo HLA typing to try to identify a well-matched donor, and then proceed quickly to allogeneic hematopoietic cell transplantation (HCT). With the introduction of imatinib followed a few years later by dasatinib, nilotinib, then bosutinib, treatment approaches changed in a dramatic way. Transplantation is no longer an upfront treatment option for newly diagnosed CML patients, and in fact, it is very rarely used in the management of a patient with CML currently. The management of CML patients has been a model of personalized medicine or targeted therapy that is being emulated in the treatment of many other hematologic malignancies and solid tumors such as lung cancer [Soverini et al. in Mol Cancer 17:49, 2018]. The Philadelphia Chromosome (Ph) which leads to the formation of the BCR-ABL fusion gene and its product the BCR-ABL protein is the cause of CML. With effective targeting of this protein with the available TKIs, the disease is completely controllable if not curable for most patients. Life expectancy for patients with CML is essentially normal. Quality of life becomes an important goal including the potential for pregnancy, and ultimately the chance to discontinue all TKI therapy permanently. The three cases outlined below serve to highlight some of the important issues in the management of patients with CML in the post-TKI era.

Management of chronic myeloid leukemia during pregnancy among patients treated with a tyrosine kinase inhibitor: a single-Center experience

Tyrosine kinase inhibitors (TKIs) are teratogenic. Chronic myeloid leukemia (CML) is increasingly identified in younger patients who wish to conceive, the management of CML during pregnancy is challenging. We reviewed 51 pregnancies involving 37 patients (30 women, 10 with >1 pregnancy and 7 men) who were either diagnosed with CML during pregnancy or receiving TKI at the time of conception. Ten women were involved in >1 pregnancies. Fifteen women were diagnosed with CML during pregnancy: 10 were treated with hydroxyurea (n = 5), interferon-alfa (n = 3), leukapheresis (n = 1), or nilotinib (n = 1). There were 14 (82%) healthy babies born on term including 2 sets of twins, 2 spontaneous miscarriages (12%), and 1 elective abortion (6%). Within 1 month of delivery or abortion, all women started TKI and achieved MR4.5 (n = 6) and MMR (n = 8) within 3-48 months. One patient, treated with interferon during pregnancy, died of blast phase within 2 months. Four of the 14 remaining women later conceived 5 other pregnancies while on TKI (3 unplanned, 2 planned). Twenty-six patients (7 men; 19 women) conceived while on TKI, with a total of 36 pregnancies. Fifteen women had 20 unplanned pregnancies while receiving TKI and discontinued immediately upon recognition of pregnancy. The median time of TKI exposure was 3 weeks (range, 2-11). Five pregnancies ended in miscarriages and 3 in elective abortion. All 7 men fathered 7 full-term healthy babies. Of 20 babies born to men and women (including one set of twins), 1 had minor abnormality. Seven women lost their responses during pregnancy but at the end of pregnancy all but 2 resumed TKI and regained responses. Seven women involved in 9 planned pregnancies discontinued TKI prior to conception for a median of 4 months (range, 1-20); 3 lost responses during pregnancy. Only 5 patients resumed therapy after delivery. Outcomes were 6 full-term healthy babies, one premature, and two miscarriages. Conception among CML patients while on TKI could be uncomplicated. While patients may lose response following treatment interruption, nearly all regain response upon resuming therapy. Therapy during pregnancy is rarely needed.

Successful Planned Pregnancy through Vitrified-Warmed Embryo Transfer in a Woman with Chronic Myeloid Leukemia: Case Report and Literature Review

A 35-year-old female patient with chronic myeloid leukemia (CML) wanted to have a child. She had been treated with imatinib and had achieved major molecular remission, after which imatinib was intentionally discontinued, and interferon-α treatment was initiated. After three failed cycles of artificial insemination with her husband’s semen, the patient underwent treatment with assisted reproductive technology. After two cycles of in vitro fertilization, two embryos (8-cell stage and blastocyst) were cryopreserved. The patient again had elevated major BCR-ABL mRNA levels; thus, infertility treatment was discontinued. After 18 months of dasatinib treatment, major molecular remission was again observed, and the patient underwent vitrified–warmed embryo transfer with a single blastocyst. After that, she became pregnant. Discontinuation of tyrosine kinase inhibitors combined with the timely initiation of infertility treatments, including assisted reproductive technology, might thus be useful for treating women with CML who wish to become pregnant.

Hematological malignancies during pregnancy

Hematological malignancy during pregnancy is a rare event, therefore most data on this issue is based on case studies, retrospective studies and expert opinion. The purpose of the present narrative review was to provide an overview of the diagnosis and recommended management of the most common hematological malignancies during pregnancy, based on current literature, with clinical cases, and discussion of the diagnostic and therapeutic options. The therapeutic consensus while coping with hematological malignancies in pregnancy is to salvage the mother, while trying to preserve pregnancy and avoid treatment-related-toxicity to the fetus. In most scenarios, particularly during late trimesters, the goal is to administer the same treatment as outside of pregnancy, if possible. Further research is needed for better evidence-based management.

The story of tyrosine kinase inhibitors discontinuation in clinical practice

Chronic myeloid leukemia is the first example of successful clinical use of tyrosine kinase inhibitors (TKIs). Blockade of oncogenic BCR-ABL1 tyrosine kinase activity by imatinib translated into an impressive demonstration of clinical and biological control of the disease. Historically, the primary objective of TKIs use was to achieve long-term survival. Today this is a reality for the majority of patients. The rapid development of BCR-ABL1 quantification by RT-qPCR has facilitated the monitoring of residual disease. Molecular response has emerged as a new therapeutic objective, opening the door to TKIs discontinuation. The first prospective stop study in patients in deep molecular response was initiated in 2004, with today nearly 15 years of follow-up. The pioneering observations of this study followed by numerous stop-studies have led to a new therapeutic goal of treatment-free remission. Five cases of patients who discontinued TKIs are reviewed, illustrating the current issues and challenges surrounding this approach.

Breastfeeding in Patients with Chronic Myeloid Leukaemia: Case Series with Measurements of Drug Concentrations in Maternal Milk and Literature Review

Breastfeeding in patients with chronic myeloid leukaemia (CML) during tyrosine kinase inhibitors (TKIs) therapy is not recommended but interruption of TKI treatment may cause the loss of remission. We studied the 3 cases of pregnancy and breastfeeding in women with CML and observed that stopping treatment without major molecular response may end in haematological relapse. The concentrations of nilotinib and imatinib in maternal milk were measured and nilotinib distribution in human breast milk was demonstrated for the first time. The estimated maximal doses of imatinib and nilotinib which an infant may ingest with the maternal milk were less than the therapeutical doses. However, the unknown impact of the low dose chronic exposure to these TKIs in infants imposes the limitations on their use during breastfeeding. Breastfeeding without TKI treatment may be safe with molecular monitoring, but preferably in those patients with CML who have durable deep molecular response.