Effects of granulocyte-colony stimulating factor on chromosome aneuploidy and replication asynchrony in healthy peripheral blood stem cell donors

Kmt2c restricts G-CSF-driven HSC mobilization and granulocyte production in a methyltransferase-independent manner

Granulocyte colony-stimulating factor (G-CSF) is widely used to enhance myeloid recovery after chemotherapy and to mobilize hematopoietic stem cells (HSCs) for transplantation. Unfortunately, through the course of chemotherapy, cancer patients can acquire leukemogenic mutations that cause therapy-related myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). This raises the question of whether therapeutic G-CSF might potentiate therapy-related MDS/AML by disproportionately stimulating mutant HSCs and other myeloid progenitors. A common mutation in therapy-related MDS/AML involves chromosome 7 deletions that inactivate many tumor suppressor genes, including KMT2C. Here, we show that Kmt2c deletions hypersensitize murine HSCs and myeloid progenitors to G-CSF, as evidenced by increased HSC mobilization and enhanced granulocyte production from granulocyte-monocyte progenitors (GMPs). Furthermore, Kmt2c attenuates the G-CSF response independently from its SET methyltransferase function. Altogether, the data raise concerns that monosomy 7 can hypersensitize progenitors to G-CSF, such that clinical use of G-CSF may amplify the risk of therapy-related MDS/AML.

Long-term follow-up of cancer and catastrophic diseases in hematopoietic stem cell donors: a comprehensive matched cohort study

Hematopoietic stem cell (HSC) transplantation, using either bone marrow (BM) or peripheral blood stem cells (PBSC), is a well-established therapy for various hematologic and non-hematologic diseases. However, the long-term health outcomes after HSC donation remain a major concern for several potential donors. Thus, we aimed to conduct a matched cohort study of 5003 unrelated donors (1099 BM and 3904 PBSC) and randomly selected 50,030 matched controls based on age, sex, and resident area from the donor registry between 1998 and 2018. The medical insurance claims of all the participants were retrieved from the Taiwan National Health and Welfare Data Science Center after de-identification. Our findings revealed no differences in the incidence of cancer, death, and catastrophic diseases between HSC donors and matched healthy participants during long-term follow-up. Kaplan-Meier curves depicting the cumulative incidence of cancer and overall mortality throughout the follow-up period also demonstrated similar outcomes between donors and non-donors. In conclusion, our results indicate that HSC donation, whether through BM or PBSC, is safe and not associated with an increased risk of cancer, death, or catastrophic diseases. These findings provide valuable information for counseling potential HSC donors and for long-term management of HSC donor health.

Absence of damaging effects of stem cell donation in unrelated donors assessed by FISH and gene variance screening

ASTRACT

Granulocyte-Colony-Stimulating factor (G-CSF) is currently the standard mobilising agent for peripheral blood stem cell (PBSC) donation. Concerns that it may trigger chromosome aberrations similar to those observed in leukaemia patients were refuted but long-term effects of G-CSF mobilisation on genome integrity remains unclear. In the setting of a multi-centre clinical trial we screened blood samples from 50 PBSC donors at cellular and gene level for aberrations common in haematological malignancies using fluorescence in situ hybridisation (FISH) and next generation sequencing (NGS) assays. Analysis of samples collected before, on the day of donation, 90 and 180 days after G-CSF admission confirmed the absence of short-term effects in PBSC donors on both quiescent and dividing cells. This data did not differ from the results of 50 individuals tested 3-5 years after bone marrow donation and 50 healthy persons. NGS using a panel targeting 54 genes recurrently affected in myeloid disorders (TruSight Myeloid panel, Illumina) showed that the gene profiles of samples from 48 PBSC donors remained stable throughout the study period. These data strongly indicate absence of detrimental effects on the genome integrity caused by PBSC donation.

The enigma of monosomy 7

Since a report of some 50 years ago describing refractory anemia associated with group C monosomy, monosomy 7 (-7) and interstitial deletions of chromosome 7 (del(7q)) have been established as one of the most frequent chromosomal aberrations found in essentially all types of myeloid tumors regardless of patient age and disease etiology. In the last century, researchers sought recessive myeloid tumor-suppressor genes by attempting to determine commonly deleted regions (CDRs) in del(7q) patients. However, these efforts were not successful. Today, tumor suppressors located in 7q are believed to act in a haploinsufficient fashion, and powerful new technologies such as microarray comparative genomic hybridization and high-throughput sequencing allow comprehensive searches throughout the genes encoded on 7q. Among those proposed as promising candidates, 4 have been validated by gene targeting in mouse models. SAMD9 (sterile α motif domain 9) and SAMD9L (SAMD9-like) encode related endosomal proteins, mutations of which cause hereditary diseases with strong propensity to infantile myelodysplastic syndrome (MDS) harboring monosomy 7. Because MDS develops in SAMD9L-deficient mice over their lifetime, SAMD9/SAMD9L are likely responsible for sporadic MDS with -7/del(7q) as the sole anomaly. EZH2 (enhancer of zeste homolog 2) and MLL3 (mixed lineage leukemia 3) encode histone-modifying enzymes; loss-of-function mutations of these are detected in some myeloid tumors at high frequencies. In contrast to SAMD9/SAMD9L, loss of EZH2 or MLL3 likely contributes to myeloid tumorigenesis in cooperation with additional specific gene alterations such as of TET2 or genes involved in the p53/Ras pathway, respectively. Distinctive roles with different significance of the loss of multiple responsible genes render the complex nature of myeloid tumors carrying -7/del(7q).

Medical and ethical considerations on hematopoietic stem cells mobilization for healthy donors

Hematopoietic stem cell transplantation is a common procedure potentially beneficial to many individuals with cancer, hematological, or inherited disorders, and has highlighted the need of related or unrelated donors to perform allograft. Donation of hematopoietic stem cells, either through bone marrow harvest or peripheral blood stem cell collection, is well-established and widespread. Over the past two decades, the peripheral blood stem cell collection by aphaeresis has become the main source of hematopoietic stem cells for transplantation, due to faster engraftment and practicability and lower risk of relapse for high-risk patients. For peripheral blood stem cell donation, donors require mobilization of hematopoietic stem cells from bone marrow into the blood stream. This is performed by growth factors injections. This article is a review of reported applications of growth factors (original granulocyte colony stimulating factor and its biosimilars), for healthy donors' peripheral blood stem cell mobilization, in terms of toxicity, side effects, efficacy and follow-up. There is still an ethical dilemma for clinicians involved in allograft, because they expose healthy donors to drugs. It is important to dispel some of the critical concerns regarding their use in healthy volunteers, particularly because they receive no personal therapeutic benefit from this procedure.

The Vitamin E Analog Gamma-Tocotrienol (GT3) Suppresses Radiation-Induced Cytogenetic Damage

Purpose

Ionizing radiation (IR) generates reactive oxygen species (ROS), which cause DNA double-strand breaks (DSBs) that are responsible for cytogenetic alterations. Because antioxidants are potent ROS scavengers, we determined whether the vitamin E isoform γ-tocotrienol (GT3), a radio-protective multifunctional dietary antioxidant, can suppress IR-induced cytogenetic damage.

Methods

We measured DSB formation in irradiated primary human umbilical vein endothelial cells (HUVECs) by quantifying the formation of γ-H2AX foci. Chromosomal aberrations (CAs) were analyzed in irradiated HUVECs and in the bone marrow cells of irradiated mice by conventional and fluorescence-based chromosome painting techniques. Gene expression was measured in HUVECs with quantitative reverse transcriptase polymerase chain reaction (qRT-PCR).

Results

GT3 pretreatment reduced DSB formation in HUVECS, and also decreased CAs in HUVECs and mouse bone marrow cells after irradiation. Moreover, GT3 increased expression of the DNA-repair gene RAD50 and attenuated radiation-induced RAD50 suppression.

Conclusions

GT3 attenuates radiation-induced cytogenetic damage, possibly by affecting RAD50 expression. GT3 should be explored as a therapeutic to reduce the risk of developing genetic diseases after radiation exposure.

Biosimilar granulocyte-colony-stimulating factor for healthy donor stem cell mobilization: need we be afraid?

Biosimilars are approved biologics with comparable quality, safety, and efficacy to a reference product. Unlike generics, which are chemically manufactured copies of small-molecule drugs with relatively simple chemical structures, the biosimilar designation is applied to drugs that are produced by living organisms, implying much more difficult to control manufacturing and purification procedures. To account for these complexities, the European Medicines Agency (EMA), the US Food and Drug Administration, the Australian Therapeutic Goods Administration, and other regulatory authorities have devised and implemented specific, markedly more demanding pathways for the evaluation and approval of biosimilars. To date, several biosimilars have been approved, including versions of somatropin, erythropoietin, and granulocyte-colony-stimulating factor (G-CSF), and several biosimilar monoclonal antibodies are currently in development. The reference G-CSF product (Neupogen, Amgen) has been used for many years for prevention and treatment of neutropenia and also for mobilization of peripheral blood stem cells (PBSCs). However, concerns have been raised about the safety and efficacy of biosimilar G-CSF during PBSC mobilization procedures, especially in healthy donors. This article reviews the available evidence on the use of biosimilar G-CSF in this setting. Aggregate clinical evidence supports the assessment by the EMA of biosimilar and originator G-CSF as highly biologically similar, with respect to desired and undesired effects.

A review of the genetic and long-term effects of G-CSF injections in healthy donors: a reassuring lack of evidence for the development of haematological malignancies

In 2007 the WMDA responded to the publication of two manuscripts suggesting a causal link between G-CSF and myeloid malignancies in healthy donors by convening an international symposium to examine this issue. At the time, registries reviewed the long-term follow-up of their healthy donors, which suggested no excess of leukaemia in PBSC donors compared with BM donors. Although the evidence for an increased risk of malignancy in healthy donors was felt to be weak, it could not be excluded. The WMDA, therefore, issued a statement, to be included in all donor consent forms, stating that it was unknown whether G-CSF increased or decreased the risk of later developing cancer. In 2012, with 5 years of additional donor follow-up and the results of several genetic studies now available, the clinical working group of the WMDA again reviewed the data. On the basis of an assessment of a continuing lack of evidence for an increased risk of malignancy in donors receiving G-CSF, the WMDA has re-issued a more reassuring statement. The revised statement was circulated to all WMDA member registries in late 2012 to replace the existing statement in consent forms, which now conclusively states that, 'Studies following large numbers of unrelated donors have shown that the risk of developing cancer within several years after the use of G-CSF is not increased compared with donors not receiving G-CSF'. Herein we review the evidence on which this statement is based.

Volunteer unrelated donor experience after administration of filgrastim and apheresis for the collection of haemopoietic stem cells: the Australian perspective

BACKGROUND

Voluntary donations of peripheral blood stem cells after administration of filgrastim (granulocyte-colony stimulating factor, G-CSF) are undertaken throughout the world by healthy individuals, but the short-, medium- and long-term adverse events during and after donation are not fully understood.

AIMS

We document the experience of donors of peripheral blood stem cells mobilised by G-CSF at Australian Bone Marrow Donor Registry collection centres.

METHODS

When the Australian Bone Marrow Donor Registry commenced collecting mobilised peripheral blood stem cells, based on data used for registration of G-CSF, all adverse reactions in donors were documented prospectively to determine the rate and severity of events. A total of 512 consecutive first-time donors assessed between July 2001 and March 2010 were included in this study.

RESULTS

The median age at work-up was 40 years and 71% of donors were male. A large proportion of donors (91%) experienced bone pain during administration of G-CSF, and in fewer numbers headache (61%) and fatigue (61%). Bone pain was associated with a body mass index of overweight/obese (P = 0.03). Headache (P = 0.03), muscle pain (P = 0.03) and fatigue (P = 0.001) were all significantly associated with female sex. More than a quarter (28%) of donations involved a range of complications at collection.

CONCLUSION

The incidence of short- and medium-term symptoms and events observed provide support for the information provided to unrelated donors at counselling. Follow up of the consequences of unrelated voluntary donation remains important to provide accurate and relevant information to prospective donors.

Administration of recombinant human granulocyte-colony-stimulating factor does not induce long-lasting detectable epigenetic alterations in healthy donors

BACKGROUND

The short-term safety profile of recombinant human granulocyte-colony-stimulating factor (rHuG-CSF) in the allogeneic stem cell setting seems acceptable; only few data on long-term safety are available. To further study possible epigenetic alterations, we investigated prospectively the influence of rHuG-CSF on DNA methyltransferase (DNMT) activity and on changes in DNA methylation of candidate genes in peripheral blood cells of healthy unrelated stem cell donors within an observation period of 1 year.

STUDY DESIGN AND METHODS

In this study, 20 stem cell donors (14 male/six female; median age, 40 years; range, 22-54 years) and 20 sex- and age-matched blood component donors (controls) were included. Sampling was performed before rHuG-CSF administration; at the time of donation; and on Days (+1), 7, 30, 100, 180, and 360 in both groups. Analysis of DNMT activity in nuclear extracts was performed using a modified radionuclide assay. We performed methylation-specific polymerase chain reaction to detect the methylation status of promoter CpG islands of the genes of the retinoic acid receptor beta (RAR-B) and the Ras association domain family 1A (RASSF1A).

RESULTS

DNMT activity increased significantly on the day of donation and 1 day after (p < 0.05). By Day +7 baseline values were reached. No further significant alterations of DNMT activity in the treated group compared to the controls were observed. We could not detect any differences in the gene methylation of RAR-B and RASSF1A between both groups.

CONCLUSION

In our prospective study no evidence of long-lasting increased DNMT activity or enhanced DNA methylation in a limited panel of target genes after recombinant human G-CSF administration was observed in healthy stem cell donors.

Lower risk for serious adverse events and no increased risk for cancer after PBSC vs BM donation

We compared serious early and late events experienced by 2726 bone marrow (BM) and 6768 peripheral blood stem cell (PBSC) donors who underwent collection of PBSC or BM between 2004 and 2009 as part of a prospective study through the National Marrow Donor Program. Standardized FDA definitions for serious adverse events (SAEs) were used, and all events were reviewed by an independent physician panel. BM donors had an increased risk for SAEs (2.38% for BM vs 0.56% for PBSC; odds ratio [OR], 4.13; P < .001), and women were twice as likely to experience an SAE (OR for men, 0.50; P = .005). Restricting the analysis to life-threatening, unexpected, or chronic/disabling events, BM donors maintained an increased risk for SAEs (0.99% for BM vs 0.31% for PBSC; OR, 3.20; P < .001). Notably, the incidence of cancer, autoimmune illness, and thrombosis after donation was similar in BM vs PBSC donors. In addition, cancer incidence in PBSC donors was less than that reported in the general population (Surveillance, Epidemiology, and End Results Program database). In conclusion, SAEs after donation are rare but more often occurred in BM donors and women. In addition, there was no evidence of increased risk for cancer, autoimmune illness, and stroke in donors receiving granulocyte colony-stimulating factor during this period of observation.

PBSC collection from family donors in Japan: a prospective survey

Severe adverse events (SAE) and late hematological malignancies have been reported after PBSC donation. No prospective data on incidence and risk factors have been available for family donors so far. The Japan Society for Hematopoietic Cell Transplantation (JSHCT) introduced therefore in 2000 a mandatory registration system. It defined standards for donor eligibility and asked harvest centers to report any SAE immediately. All donors were examined at day 30 and were to be contacted once each year for a period of 5 years. Acute SAEs within day 30 were reported from 47/3264 donations (1.44%) with 14 events considered as unexpected and severe (0.58%). No donor died within 30 days. Late SAEs were reported from 39/1708 donors (2.3%). The incidence of acute SAEs was significantly higher among donors not matching the JSHCT standards (P=0.0023). Late hematological malignancies in PBSC donors were not different compared with a retrospective cohort of BM donors (N:1/1708 vs N:2/5921; P=0.53). In conclusion, acute and late SAEs do occur in PBSC donors at relatively low frequency but risk factors can be defined.

G-CSF in Healthy Allogeneic Stem Cell Donors

Mobilization of peripheral blood stem cells (PBSC) in healthy volunteers with granulocyte colony-stimulating factor (G-CSF) is currently carried out at many institutions worldwide. This report presents the experience of the Dresden center regarding donor evaluation and mobilization schedule. Data regarding efficacy, short- and long-term safety of G-CSF treatment gained from 8290 PBSC collections in healthy donors are outlined. These results are discussed against the background of the available evidence from the literature. Although established as a standard procedure, G-CSF application to allogeneic donors will always be a very delicate procedure and requires the utmost commitment of all staff involved to ensure maximum donor safety.

Safety and efficacy of healthy volunteer stem cell mobilization with filgrastim G-CSF and mobilized stem cell apheresis: results of a prospective longitudinal 5-year follow-up study

BACKGROUND AND OBJECTIVES

G-CSF-mobilized peripheral blood stem cells have long replaced marrow as the major source for allogeneic transplants. Conclusive evidence questioning the long-term safety of G-CSF for donors has not been provided, but the cumulative number of followed donors remains insufficient to rule out rare adverse events. A long-term active follow-up study of G-CSF-mobilized healthy volunteer donors was therefore performed.

PATIENTS AND METHODS

Two hundred and three successive donors were evaluated pre-apheresis, subjected to G-CSF-mobilization/apheresis, and actively followed for 5 years by the same physicians and laboratories. Follow-up laboratory work included standard biochemical/haematological tests and T-cell phenotyping.

RESULTS

Donor epidemiology was typical for reported stem cell donor cohorts. Acute adverse effects of G-CSF and apheresis were mild and transient, consistent with the previous reports. Mean circulating CD34(+) cells after nine doses of G-CSF were 124 per μl. Other biochemical/haematological parameters were also altered, consistent with G-CSF treatment. Spleen enlargement was modest. At first follow-up, all clinical and laboratory parameters had normalized. Leucocyte/lymphocyte counts and CD4/CD8 ratios were the same as during premobilization work-up and remained unchanged throughout. A single severe but likely unrelated adverse event, a case of papillary thyroid carcinoma, was reported.

CONCLUSION

The studies add an observation time of almost 500 donor years to the growing body of evidence of the long-term safety of G-CSF for allogeneic donor stem cell mobilization.

Allogeneic hematopoietic stem cell donation-standardized assessment of donor outcome data: a consensus statement from the Worldwide Network for Blood and Marrow Transplantation (WBMT)

The number of allogeneic hematopoietic SCTs performed globally each year continues to increase, paralleled by an increased demand for donors of therapeutic cells. Donor characteristics and collection procedures have undergone major changes during recent decades, and further changes are foreseen. Information on short- and long-term donor outcomes is of crucial importance to ensure maximal donor safety and availability. Current data, predominantly from unrelated donors, give reliable information on the frequent early events associated with donation-most of them of mild-to-moderate intensity. Information on the type and relative risk of serious adverse reactions is more limited. Moreover, only few data exist on long-term donor outcome. On the basis of this need, recommendations for a minimum data set for prospective donor follow-up were developed in a workshop with the participation of an international group of investigators actively involved in allogeneic stem cell donation under the auspices of and approved by the Worldwide Network for Blood and Marrow Transplantation. Establishment of a standardized global follow-up for both, related and unrelated, donors will enable monitoring of the short- and long-term safety profiles of hematopoietic cell donation and form a solid basis for future donor selection and counseling.