Durable complete remission after single agent decitabine in AML relapsing in extramedullary sites after allo-SCT

Myeloid sarcoma: more and less than a distinct entity

Myeloid sarcoma (MS) is a distinct entity among myeloid neoplasms defined as a tumour mass of myeloid blasts occurring at an anatomical site other than the bone marrow, in most cases concomitant with acute myeloid leukaemia (AML), rarely without bone marrow involvement. MS may also represent the blast phase of chronic myeloproliferative neoplasms (MPN) and myelodysplastic syndromes (MDS). However, the clinical and molecular heterogeneity of AML, as highlighted by the 2022 World Health Organization (WHO) and International Consensus (ICC) classifications, indirectly define MS more as a set of heterogeneous and proteiform diseases, rather than a homogeneous single entity. Diagnosis is challenging and relies mainly on histopathology, immunohistochemistry, and imaging. Molecular and cytogenetic analysis of MS tissue, particularly in isolated cases, should be performed to refine the diagnosis, and thus assign prognosis guiding treatment decisions. If feasible, systemic therapies used in AML remission induction should be employed, even in isolated MS. Role and type of consolidation therapy are not univocally acknowledged, and systemic therapies, radiotherapy, or allogeneic hematopoietic stem cell transplantation (allo-HSCT) should be considered. In the present review, we discuss recent information on MS, focusing on diagnosis, molecular findings, and treatments also considering targetable mutations by recently approved AML drugs.

Pediatric Myeloid Sarcoma, More than Just a Chloroma: A Review of Clinical Presentations, Significance, and Biology

Myeloid sarcomas (MS), commonly referred to as chloromas, are extramedullary tumors of acute myeloid leukemia (AML) with varying incidence and influence on outcomes. Pediatric MS has both a higher incidence and unique clinical presentation, cytogenetic profile, and set of risk factors compared to adult patients. Optimal treatment remains undefined, yet allogeneic hematopoietic stem cell transplantation (allo-HSCT) and epigenetic reprogramming in children are potential therapies. Importantly, the biology of MS development is poorly understood; however, cell-cell interactions, epigenetic dysregulation, cytokine signaling, and angiogenesis all appear to play key roles. This review describes pediatric-specific MS literature and the current state of knowledge about the biological determinants that drive MS development. While the significance of MS remains controversial, the pediatric experience provides an opportunity to investigate mechanisms of disease development to improve patient outcomes. This brings the hope of better understanding MS as a distinct disease entity deserving directed therapeutic approaches.

Azacitidine and donor lymphocytes infusions in acute myeloid leukemia and myelodysplastic syndrome relapsed after allogeneic hematopoietic stem cell transplantation from alternative donors

Introduction

Azacitidine (AZA) either single-agent or with donor lymphocytes infusions (DLI) has been used as a salvage treatment for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) relapsing after allogeneic hematopoietic stem cell transplantation (HSCT). To date, the majority of data come from patients relapsed after HSCT from full-matched donors.

Methods

We report a multicenter, collaborative, retrospective analysis of 71 patients with hematologic (n = 40, 56%) and molecular relapse (n = 31, 44%) of myeloid neoplasms after HSCT from alternative donors (mismatched unrelated, n = 39, 55%; haploidentical, n = 29, 41%) consecutively treated at three European centers with AZA ± DLI.

Results

Median time from HSCT to relapse was 9 months. Additional DLI were given to 33 patients (46%). After a median of four cycles, overall response rate (ORR) was 49% and complete response (CR) rate was 38%. CR lasted for a median of 17 months (range 5-89 months). Median follow-up in the entire cohort was 11 months (range 1-115 months). Event-free survival (EFS) and overall survival (OS) at 1 year were 26% and 53%, respectively. Treatment of molecular relapse granted higher CR rate (65% versus 15%; p = 0.0001), 1-year EFS (43% versus 13%; p = 0.006), and 1-year OS (79% versus 34%; p < 0.001) compared to hematologic relapses. Addition of DLI resulted in significantly higher responses and longer 1-year EFS and OS (Mantel-Byar test, p = 0.004 and p = 0.002, respectively). When applied to our cohort, the APSS-R score confirmed its ability to stratify patients into distinct prognostic groups with significantly different response rates (p = 0.0005) and survival (p < 0.0001). Treatment was well tolerated, with the incidence of late acute and chronic graft-versus-host disease of 27% and 18%, respectively.

Conclusion

AZA ± DLI proved feasible and effective in AML and MDS relapsing after HSCT from alternative donors. Despite modest efficacy among hematologic relapses, pre-emptive treatment with AZA ± DLI fared better in molecular relapse. Additional DLI contributed to improving efficacy and ensuring longer survival.

Clinical characteristics, treatment, and prognosis of 118 cases of myeloid sarcoma

Myeloid sarcoma is a rare manifestation of acute myeloid leukemia (AML) and is associated with poor overall survival (OS). The optimal treatment remains unclear. The study retrospectively evaluated 118 patients with myeloid sarcoma who were treated at the First Affiliated Hospital of Zhengzhou University from January 2010 to July 2021. All cases were diagnosed by tissue biopsy. 41 patients underwent genetic mutation analysis. The most frequent genetic mutations were KIT (16.6%), followed by TET2 (14.6%), and NRAS (14.6%). The median survival time of 118 patients was 4 months (range, 1–51 months), while the median survival time of 11 patients who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) was 19 months (range, 8–51 months). 4 (36.4%) of the 11 patients experienced relapse within 1 year after transplantation. 1 patient died from a severe infection. Of the 6 surviving patients, 5 patients have received maintenance treatment with decitabine after transplantation, and all remained in a state of recurrence-free survival. Patients with myeloid sarcoma have a very unfavorable outcome. Allo-HSCT is an effective treatment option. Recurrence remains the main cause of transplant failure. Maintenance treatment with decitabine after transplantation can prolong the recurrence-free survival time, although these results must be verified in a study with expanded sample size.

Strategic enhancement of immune checkpoint inhibition in refractory Colorectal Cancer: Trends and future prospective

Colorectal cancer (CRC), known as a frequently fatal disease, ranking as the third most common malignancy, is the second leading cause of cancer related mortality worldwide. Metastases are common in CRC patients which account for approximately 25% of the patients at diagnosis, 50% of patients during treatment which is associated closely with CRC mortality. Conventional therapies such as surgery, chemotherapy, and radiotherapy are standards of care for the treatment of CRC patients. However, primary tumor recurrence and secondary disease in patients receiving standard of care treatment modalities occur in 50% of patients so that new treatment modalities are needed. Immune checkpoint inhibition (ICI) has transformed the management of patients suffered from metastatic CRC (mCRC) with mismatch repair deficiency (dMMR) and microsatellite instability (MSI) -high (MSI-H) while manifests ineffectiveness in preserved mismatch repair (pMMR) or microsatellite stable (MSS) "cold" tumors which makes up the majority (95%) of mCRC. In this review, we mainly lay emphasis on the development of combinations in therapy strategies with ICIs with other immune based treatment approaches to increase the intra-tumoral immune response and render tumors 'immune-reactive', thereby increasing the efficacy of tumor immunotherapy.

Successful Treatment of Myeloid Sarcoma in an Elderly Patient with Myelodysplastic Syndrome with Reduced-Dose Azacitidine

Myeloid sarcoma (MS), which involves extramedullary lesions, is classified as a unique subtype of acute myeloid leukemia (AML). At present, no standard treatments for MS have been established. The patient was an 89-year-old man with myelodysplastic syndrome-excess blast-2 (MDS-EB-2) with a 2-year history of intermittent treatment with azacitidine (AZA) during a 4-year history of MDS. He developed painful cutaneous tumors 8 months after the second discontinuation of AZA. They were refractory for antibiotics and topical tacrolimus hydrate. A tumor biopsy was performed, and the histological findings of the tumor lesion showed a proliferation of tumor cells that were positive for myeloperoxidase and CD68 and negative for CD4 and CD123. The patient was diagnosed with MDS-associated MS. MDS-EB-2 quickly progressed to AML with the appearance of peripheral blood blasts and 25% bone marrow blasts. Monotherapy with reduced-dose AZA (37.5 mg/m² for 7 days, every 4–6 weeks) was restarted, and the MS quickly disappeared. The patient's MS was successfully treated with 16 cycles of AZA treatment over a 22-month period. There have been 10 reported cases in which MS was successfully treated with AZA. Among the 10 cases, the patient in the present case was the oldest. Treatment with reduced-dose AZA should be considered as a therapeutic option for MS in elderly patients with MDS, especially patients who are ineligible for intensive chemotherapy.

Hypomethylating Agents and Immunotherapy: Therapeutic Synergism in Acute Myeloid Leukemia and Myelodysplastic Syndromes

Decitabine and guadecitabine are hypomethylating agents (HMAs) that exert inhibitory effects against cancer cells. This includes stimulation of anti-tumor immunity in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) patients. Treatment of AML and MDS patients with the HMAs confers upregulation of cancer/testis antigens (CTAs) expression including the highly immunogenic CTA NY-ESO-1. This leads to activation of CD4⁺ and CD8⁺ T cells for elimination of cancer cells, and it establishes the feasibility to combine cancer vaccine with HMAs to enhance vaccine immunogenicity. Moreover, decitabine and guadecitabine induce the expression of immune checkpoint molecules in AML cells. In this review, the accumulating knowledge on the immunopotentiating properties of decitabine and guadecitabine in AML and MDS patients are presented and discussed. In summary, combination of decitabine or guadecitabine with NY-ESO-1 vaccine enhances vaccine immunogenicity in AML patients. T cells from AML patients stimulated with dendritic cell (DC)/AML fusion vaccine and guadecitabine display increased capacity to lyse AML cells. Moreover, decitabine enhances NK cell-mediated cytotoxicity or CD123-specific chimeric antigen receptor-engineered T cells antileukemic activities against AML. Furthermore, combination of either HMAs with immune checkpoint blockade (ICB) therapy may circumvent their resistance. Finally, clinical trials of either HMAs combined with cancer vaccines, NK cell infusion or ICB therapy in relapsed/refractory AML and high-risk MDS patients are currently underway, highlighting the promising efficacy of HMAs and immunotherapy synergy against these malignancies.

Durable Remission of Chemotherapy-Refractory Myeloid Sarcoma by Azacitidine

Myeloid sarcoma is a rare disease entity of extramedullary myeloid neoplasm that can occur both as an initial isolated myeloid sarcoma without leukemic cell invasion in the peripheral blood and bone marrow, and as the secondary lesion of acute and chronic myeloid leukemias, myelodysplastic syndrome and chronic myeloproliferative neoplasms. Due to its rarity and its frequent emergence as the recurrent lesion after intensive systemic therapy, including allogeneic hematopoietic stem cell transplantation, the standard treatment has not been established for myeloid sarcoma. In this report, we presented an 84-year-old female patient with isolated myeloid sarcoma which progressed to myelodysplastic syndrome and systemic myeloid sarcoma despite various types of conventional anti-leukemic chemotherapies. However, the patient got a durable partial response by the monotherapy of azacitidine, a hypomethylating agent. She received thirteen courses of azacitidine therapy without progression. We discuss the possibility that hypomethylating agents are the novel effective and feasible therapeutic options for myeloid sarcoma, even in cases refractory to or relapsed after intensive systemic treatment. We also discuss the possible future development of hypomethylating agent-containing combinatory therapeutic strategy for myeloid sarcoma, given its direct anti-leukemic effect and immunomodulatory effect.

Post-transplant leukemia relapse in organs: biology. and behavior in 585 reports

Resistance of extramedullary leukemia growth post-transplant prevents cure. Review of its behavior detailed in 585 published cases should lead to better treatment. Leukemic tumors were found up to 13 years after transplant, most in sites inaccessible to physical exam. In 83%, marrow was not in morphologic relapse; next relapse was most often extramedullary. Induction protocols alone produced few durable responses in acute leukemias and fatal marrow aplasia in 17 %. Overall, 120 patients survived over 2 years, 43 relapse-free up to 18 years, the majority after combined tumor-directed and systemic therapy. Overall median survival was 9 months. This review highlights how results can improve: by defining extent of leukemia involvement with scans before transplant, and emergently when leukemic tumor is found after, ablating tumor directly to abort metastasis, and determining dosing of systemic chemotherapy that protects, without ablating, donor marrow. Monitoring total body remission with body scans should increase transplant cures.

Myeloid sarcoma, chloroma, or extramedullary acute myeloid leukemia tumor: A tale of misnomers, controversy and the unresolved

The World Health Organization classification and definition of "myeloid sarcoma" is imprecise and misleading. A more accurate term is "extramedullary acute myeloid leukemia tumor (eAML)." The pathogenesis of eAML has been associated with aberrancy of cellular adhesion molecules, chemokine receptors/ligands and RAS-MAPK/ERK signaling. eAML can present with or without synchronous or metachronous intramedullary acute myeloid leukemia (AML) so a bone marrow evaluation is always recommended. Accurate diagnosis of eAML requires tissue biopsy. eAML confined to one or a few sites is frequently treated with local therapy such as radiotherapy. About 75-90% of patients with isolated eAML will develop metachronous intramedullary AML with a median latency period ranging from 4 to 12 months; thus, patients with isolated eAML may also be treated with systemic anti-leukemia therapy. eAML does not appear to have an independent prognostic impact; selection of post-remission therapy including allogeneic hematopoietic cell transplant (alloHCT) is typically guided by intramedullary disease risk. Management of isolated eAML should be individualized based on patient characteristics as well as eAML location and cytogenetic/molecular features. The role of PET/CT in eAML is also currently being elucidated. Improving outcomes of patients with eAML requires further knowledge of its etiology and mechanism(s) as well as therapeutic approaches beyond conventional chemotherapy, ideally in the context of controlled trials.

Long-Lasting Remission in De Novo Breast Myeloid Sarcoma Treated with Decitabine and Radiotherapy

Myeloid sarcoma (MS) represents a rare disease with an adverse clinical outcome for patients not candidate to acute myeloid leukemia (AML)-like chemotherapies. Here we present the case of an elderly patient affected by a bilateral breast localization of MS treated with the hypomethylating agent decitabine associated to radiotherapy. The association of the two treatment modalities has allowed an optimal and long-lasting disease control.

Low-dose decitabine enhances the effect of PD-1 blockade in colorectal cancer with microsatellite stability by re-modulating the tumor microenvironment

PD-1 blockade has demonstrated impressive clinical outcomes in colorectal cancers that have high microsatellite instability. However, the therapeutic efficacy for patients with tumors with low microsatellite instability or stable microsatellites needs further improvement. Here, we have demonstrated that low-dose decitabine could increase the expression of immune-related genes such as major histocompatibility complex genes and cytokine-related genes as well as the number of lymphocytes at the tumor site in CT26 colorectal cancer-bearing mice. A more significant inhibition of tumor growth and a prolongation of survival were observed in the CT26 mouse model after treatment with a combination of PD-1 blockade and decitabine than in mice treated with decitabine or PD-1 blockade alone. The anti-tumor effect of the PD-1 blockade was enhanced by low-dose decitabine. The results of RNA sequencing and whole-genome bisulfite sequencing of decitabine-treated CT26 cells and tumor samples with microsatellite stability from the patient tumor-derived xenograft model have shown that many immune-related genes, including antigen-processing and antigen-presenting genes, were upregulated, whereas the promoter demethylation was downregulated after decitabine exposure. Therefore, decitabine-based tumor microenvironment re-modulation could improve the effect of the PD-1 blockade. The application of decitabine in PD-1 blockade-based immunotherapy may elicit more potent immune responses, which can provide clinical benefits to the colorectal cancer patients with low microsatellite instability or stable microsatellites.

DNA-hypomethylating agents as epigenetic therapy before and after allogeneic hematopoietic stem cell transplantation in myelodysplastic syndromes and juvenile myelomonocytic leukemia

Myelodysplastic syndrome (MDS) is a clonal bone marrow disorder, typically of older adults, which is characterized by ineffective hematopoiesis, peripheral blood cytopenias and risk of progression to acute myeloid leukemia. Juvenile myelomonocytic leukemia (JMML) is an aggressive myeloproliferative neoplasm occurring in young children. The common denominator of these malignant myeloid disorders is the limited benefit of conventional chemotherapy and a particular responsiveness to epigenetic therapy with the DNA-hypomethylating agents 5-azacytidine (azacitidine) or decitabine. However, hypomethylating therapy does not eradicate the malignant clone in MDS or JMML and allogeneic hematopoietic stem cell transplantation (HSCT) remains the only curative treatment option. An emerging concept with intriguing potential is the combination of hypomethylating therapy and HSCT. Possible advantages include disease control with good tolerability during donor search and HSCT preparation, improved antitumoral alloimmunity, and reduced risk of relapse even with non-myeloablative regimens. Herein we review the current role of pre- and post-transplant therapy with hypomethylating agents in MDS and JMML.

An unusual type of myeloid sarcoma localization following myelofibrosis: A case report and literature review

Myeloid Sarcoma (MS) is a rare malignancy that can present as an isolated disease or more frequently in association with or following acute myeloid leukemia or other myeloid neoplasms and rarely following myelofibrosis.

Since molecular pathogenesis and prognostic factors of MS are not well understood, its prognosis remains poor even in the era of novel agents and target therapies.

We report the case of a patient with MS following myelofibrosis with multiple subcutaneous, cutaneous and muscle localizations; the latter has been reported in the literature as anecdotal. In this way we aimed to enhance the understanding of this disease.

Hypomethylating agents after allogeneic blood stem cell transplantation

Allogeneic blood stem cell transplantation (allo-SCT) is a potentially curative treatment for patients with myeloid malignancies such as acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), but relapse remains the major cause of treatment failure. So far, therapeutic options for patients with AML or MDS who relapse after allo-SCT generally consisted of palliative care, low-dose or intensive chemotherapy as well as cellular therapies such as donor lymphocyte infusions (DLI) and second transplantation in selected cases. Nevertheless, the prognosis of patients with myeloid malignancies relapsing after allo-SCT remains dismal therefore asking for novel treatment strategies. Considering their well-balanced profile of good efficacy and moderate toxicity in the non-transplant setting, the hypomethylating agents (HMA) azacitidine (Aza) and decitabine (DAC) have also been tested either alone or in combination with DLI in the post-transplant period. This review summarizes the current knowledge about the use of these two HMA as pre-emptive, salvage or consolidation therapy mostly retrieved from retrospective studies but also from a few prospective trials. Within this review, we also comment on some practical issues such as optimal dose and schedule, the choice of HMA candidates and the role of additional cellular interventions. Finally, we also give an overview on the assumed mode of actions, ongoing research, clinical studies and potential combination partners aiming to improve this treatment approach.

18 FDG-PET/CT: 21st century approach to leukemic tumors in 124 cases

Extramedullary tumors remain an obstacle to curing more acute leukemia patients. Their incidence is unknown because the presence of occult tumors that contribute to relapse is not routinely sought as in other cancers. No standard approach exists for treating tumors at most sites, apparent clinical response is typically followed by further tumors, and achievement of lengthy remission is uncommon. Body scanning with (18) FDG PET/CT now provides a means to identify the extent of occult tumors that enables directed tumor eradication and a way to evaluate tumor response. To evaluate its potential benefits, analysis was undertaken of 124 published cases scanned after apparent tumors were diagnosed. Clinical and radiologic exams underestimated extent of disease in over half of 100 cases. Among 70 cases that reported scans after various treatments, 70% achieved negative scans. Half relapsed subsequently but disease-free survivals up to 6 years were documented. These reported cases add to our knowledge of extramedullary leukemia in showing that further tumors are more likely than marrow relapse, clinical and radiologic evaluation of response is inadequate, intensive chemotherapy alone generally does not prevent progression and is associated with significant mortality, and tumor-directed plus systemic therapies appears the most effective approach, particularly to AML tumors. This analysis suggests this technology could increase our ability to eradicate all foci of leukemia, and identify tumors responsible for refractory, residual, and relapsed disease.

Primary vaginal myeloid sarcoma: a rare case report and review of the literature

Myeloid sarcoma (chloroma, granulocytic sarcoma, or extramedullary myeloid tumour) is an extramedullary mass forming neoplasm composed of myeloid precursor cells. It is usually associated with myeloproliferative disorders but very rarely may precede the onset of leukemia. Here, we are presenting a rare case of primary vaginal myeloid sarcoma in a geriatric female patient without initial presentation of acute myeloid leukemia (AML). A 68-year-old female patient with ECOG Performance Score of 1 presented with pervaginal bleeding for 20 days. On colposcopic examination, she was found to have mass in the anterior fornix of vagina. A punch biopsy specimen revealed chloromatous infiltration of the vagina. LCA (leukocyte common antigen), MPO (myeloperoxidase), and c-kit were strongly positive on IHC (immunohistochemistry). The patient's routine blood investigations were normal including peripheral smear, lactose dehydrogenase, uric acid, 2D echocardiography, conventional cytogenetics, bone marrow aspiration, and biopsy. The patient was given 4 cycles of decitabine (Decitex, manufactured by Sun Pharmaceutical Industries Limited, India), 20 mg/m(2) for 5 days at an interval of 28 days. There was a partial response to decitabine according to RECIST criteria. As decitabine therapy was well tolerated, we are continuing in the same way until disease progression without any complications. The patient is undergoing regular follow-up at our centre.

Extramedullary relapse of acute leukemia after allogeneic hematopoietic stem cell transplantation: different characteristics between acute myelogenous leukemia and acute lymphoblastic leukemia

Extramedullary relapse (EMR) of acute leukemia (AL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a contributor to post-transplantation mortality and remains poorly understood, especially the different characteristics of EMR in patients with acute myelogenous leukemia (AML) and those with acute lymphoblastic leukemia (ALL). To investigate the incidence, risk factors, and clinical outcomes of EMR for AML and ALL, we performed a retrospective analysis of 362 patients with AL who underwent allo-HSCT at the First affiliated Hospital of Soochow University between January 2001 and March 2012. Compared with patients with AML, those with ALL had a higher incidence of EMR (12.9% versus 4.6%; P = .009). The most common site of EMR was the central nervous system, especially in the ALL group. Multivariate analyses identified the leading risk factors for EMR in the patients with AML as advanced disease status at HSCT, hyperleukocytosis at diagnosis, history of extramedullary leukemia before HSCT, and a total body irradiation-based conditioning regimen, and the top risk factors for EMR in the patients with ALL as hyperleukocytosis at diagnosis, adverse cytogenetics, and transfusion of peripheral blood stem cells. The prognosis for EMR of AL is poor, and treatment options are very limited; however, the estimated 3-year overall survival (OS) was significantly lower in patients with AML compared with those with ALL (0 versus 18.5%; P = .000). The characteristics of post-allo-HSCT EMR differed between the patients with AML and those with ALL, possibly suggesting different pathogenetic mechanisms for EMR of AML and EMR of ALL after allo-HSCT; further investigation is needed.