The myeloid sarcoma treated by Venetoclax with hypomethylating agent followed by stem cell transplantation: rare case report

Real-world experience with venetoclax-based therapy for patients with myeloid sarcoma

BACKGROUND

The treatment of myeloid sarcoma (MS) is challenging and has not markedly improved patient prognosis. The introduction of venetoclax (VEN) has changed the treatment of MS, and venetoclax-based therapy has been described as very promising in several case reports.

METHODS

In this retrospective study, we analyzed the treatment outcomes of 14 patients with MS treated with venetoclax-based therapy at The First Affiliated Hospital of Xiamen University from January 2020 to October 2023 RESULTS: The cohort consisted of 7 (50%) women and 7 (50%) men with an average age of 37.5 years. Four patients (28.6%) had isolated MS de novo, 2 (14.2%) were diagnosed synchronously with AML, and 8 (57.2%) had isolated extramedullary relapse. The most common sites for MS in our cohort were the skin and lung, followed by the spinal canal, soft tissue, bone and kidney. Five patients were affected at more than three sites. Nine patients received VEN in combination with azacytidine, and 5 patients received VEN in combination with other agents. The median number of venetoclax therapies administered was 2 cycles (range: 1-10 cycles). A response was observed in all patients included in the study, with 8 patients (57.2%) achieving a CR and 3 patients (21.4%) achieving a PR, corresponding to an ORR (including CR and PR) of 78.6%. The median follow-up time for all patients was 13 months (range 1-44 months), and the 1 year OS for all patients was 67.7%.

CONCLUSIONS

Venetoclax-based therapy shows excellent efficacy and safety in MS patients in the "real world" at a single institution, and a corresponding prospective study is needed to verify this conclusion.

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.

Myeloid sarcoma: An overview

Myeloid Sarcoma (MS) is a high grade, hematological malignancy defined as an extramedullary tumor mass of myeloid blasts with or without maturation that effaces tissue architecture. It is a highly heterogenous condition that represents a variety of myeloid neoplasms. This heterogeneity of MS, together with its rarity, have greatly hampered our understanding of the condition. Diagnosis requires tumor biopsy, which should be accompanied by bone marrow evaluation for medullary disease. It is presently recommended that MS be treated similar to AML. Additionally, ablative radiotherapy and novel targeted therapies may also be beneficial. Genetic profiling has identified recurrent genetic abnormalities including gene mutations associated with MS, supporting its etiology similar to AML. However, the mechanisms by which MS homes to specific organs is unclear. This review provides an overview of pathogenesis, pathological and genetic findings, treatment, and prognosis. Improving the management and outcomes of MS patients requires a better understanding of its pathogenesis and its response to various therapeutic approaches.

Orbital myeloid sarcoma treated with low-dose venetoclax and a potent cytochrome P450 inhibitor

CASE REPORT

We report the first case of orbital myeloid sarcoma that was successfully treated with a standard venetoclax dose of 25%. A 38-year-old man with acute myeloid leukemia (AML) post-haplo-hematopoietic stem cell transplantation (HSCT) presented with a nine-month history of progressive right proptosis and a visual acuity deficit. The patient was treated with venetoclax (100 mg orally on days 1-28), cytarabine (40 mg subcutaneously, days 1-10), and itraconazole (100 mg twice daily orally on days 1-28).

MANAGEMENT AND OUTCOME

The present case report shows that using cytochrome P450 (CYP) inhibitors is a helpful strategy to reduce the cost of expensive treatments.

DISCUSSION

There are limited data on the use of CYP inhibitors as a strategy to reduce the costs of expensive drugs (i.e. venetoclax). This approach has some advantages over standard dose venetoclax (400 mg/day) such as significantly reduced costs (which is relevant for patients in low-income countries). In this case, we used itraconazole-a potent CYP3A4 inhibitor-which can theoretically reduce the dose to 100 mg/day without losing serum therapeutic concentrations.

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.

Long‐term remission of extramedullary cutaneous relapse of acute myeloid leukaemia (leukaemia cutis) treated with decitabine‐venetoclax

In February 2020, a 74‐year‐old female was diagnosed with myelomonocytic acute myeloid leukaemia with FLT3 mutation and blasts positive for CD33, BCL‐2 and CD68/PGM1. Not responding to a standard Cytarabine–containing regimen plus Midostaurin, the patient achieved a complete remission (CR) of the disease in the bone marrow following a reinduction therapy with high‐dose Cytarabine but simultaneously relapsed developing leukaemia cutis with disseminated lesions in 80% of the body surface area. After receiving 10 cycles of Decitabine plus Venetoclax the patient achieved and maintains a continuous CR.

Target Therapy for Extramedullary Relapse of FLT3-ITD Acute Myeloid Leukemia: Emerging Data from the Field

FMS-like tyrosine kinase 3 (FLT3) is a receptor tyrosine kinase family member. Mutations in FLT3, as well known, represent the most common genomic alteration in acute myeloid leukemia (AML), identified in approximately one-third of newly diagnosed adult patients. In recent years, this has represented an important therapeutic target. Drugs such as midostaurin, gilteritinib, and sorafenib, either alone in association with conventional chemotherapy, play a pivotal role in AML therapy with the mutated FLT3 gene. A current challenge lies in treating forms of AML with extramedullary localization. Here, we describe the general features of myeloid sarcoma and the ability of a targeted drug, i.e., gilteritinib, approved for relapsed or refractory disease, to induce remission of these extramedullary leukemic localizations in AML patients with FLT3 mutation, analyzing how in the literature, there is an important development of cases describing this promising potential for care.

The Progression of Chronic Myeloid Leukemia to Myeloid Sarcoma: A Systematic Review

Chronic myeloid leukemia (CML) is a slow-growing type of cancer that originates in the blood-forming cells of the bone marrow and is caused by a chromosomal mutation that is thought to occur spontaneously. CML could potentially lead to the development of myeloid sarcoma (MS), which is a rare neoplasm composed of immature myeloid cells that could evolve into a tumor mass at any anatomical site other than the bone marrow. MS can develop spontaneously or as a result of another form of myeloid neoplasm. Most instances of CML precede blast phase (BP) within two to three years after the first diagnosis of CML chronic phase (CP) at the age of pre-tyrosine kinase inhibitor (TKI) treatment. MS developing in CML patients during the era of TKI treatment is infrequently mentioned in the literature, primarily in single-case studies. As a result, the prognostic influence of MS in CML patients has not been well investigated. In the age of TKI treatment, it is uncertain whether MS and medullary BP have comparable clinical and prognostic relevance. The precise diagnosis of MS is critical for effective treatment, which is frequently delayed due to a high risk of misdiagnosis. This review focuses on the relationship between the development of MS from CML, and it culminates with recommendations for future hematology practice. A literature search was conducted in multiple databases, and the studies were appraised based on the inclusion and exclusion criteria. Finally, studies to date have shown that the existence of CML and its possible progression to MS in individuals map out the numerous implications this disease has in hematology practice. Though occurrences are uncommon in general, the prognosis for patients is bleak, necessitating the exploration and implementation of diagnostic and therapy advancements. Because there is limited evidence in the literature on its existence in the medullary chronic phase and outcomes in the era of TKI, it must be carefully investigated because it might be the first symptom of progressive illness prior to hematological progression.