Maintenance Therapy in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) poses significant challenges due to its high relapse rates despite initial successful induction chemotherapy. Maintenance therapy aims to prevent disease recurrence, particularly in high-risk patients. This review explores current maintenance treatments, their impacts on patient outcomes, and ongoing studies shaping the treatment landscape for AML. Hypomethylating agents like azacitidine and decitabine have shown promise in improving relapse-free and overall survival, particularly in older patients with AML ineligible for transplantation. Combination regimens involving azacitidine and venetoclax have demonstrated encouraging outcomes post-hematopoietic stem cell transplantation. Targeted therapies, particularly FLT3 inhibitors like midostaurin and quizartinib, have shown significant benefits in improving survival outcomes, especially in FLT3-mutated AML cases. Gilteritinib and sorafenib also exhibit the potential to reduce relapse rates post-transplant. Isocitrate dehydrogenase inhibitors, including ivosidenib and enasidenib, present novel options for postchemotherapy and posttransplantation maintenance. Immunotherapies, such as Wilms tumor 1 peptide-based vaccines and checkpoint inhibitors, are being explored, although results vary. Despite ongoing research, the role of maintenance chemotherapy remains uncertain, with inconsistent outcomes across trials. The approval of oral azacitidine represents a significant advancement, emphasizing the need for further investigation into personalized maintenance approaches. In conclusion, the evolving landscape of maintenance therapy and integrating targeted therapies in AML offers promising avenues for improving patient outcomes.

Sabakhtarishvili G ，Ansari A ，Tabbara IA 《-》

Quizartinib: a potent and selective FLT3 inhibitor for the treatment of patients with FLT3-ITD-positive AML.

Mutations in FMS-related receptor tyrosine kinase 3 (FLT3) are among the most common alterations in acute myeloid leukemia (AML), present in ≈30% of newly diagnosed AML cases. Internal tandem duplications (ITD) in FLT3 (FLT3-ITD) occur in ≈25% of newly diagnosed AML cases and are associated with unfavorable outcomes. Quizartinib (formerly AC220) is a novel, second-generation, highly potent, and selective type II FLT3 inhibitor. Quizartinib is approved in Japan as monotherapy for the treatment of adult patients with FLT3-ITD-positive relapsed/refractory (R/R) AML. Quizartinib is also approved in the United States, Japan, Europe, and United Kingdom in combination with chemotherapy during induction and consolidation, and as maintenance monotherapy (but, in the United States, not after allogeneic hematopoietic cell transplantation [allo-HCT]), for the treatment of adult patients with newly diagnosed FLT3-ITD-positive AML. In this review, we summarize preclinical studies that established quizartinib as a potent and selective type II FLT3 inhibitor as well as early and pivotal phase 3 clinical studies (QuANTUM-R and QuANTUM-First) that led to the approvals of quizartinib. We also summarize mechanisms of resistance to quizartinib along with its safety profile. Furthermore, we review the ongoing post hoc analyses of the QuANTUM-First data elucidating the impact of allo-HCT, the presence of measurable residual disease, and number and length of ITD on the clinical outcomes of quizartinib. We also describe the impact of quizartinib on patient-reported outcomes. Finally, we highlight some of the ongoing studies that test quizartinib in patients with FLT3-ITD-positive AML, patients with FLT3-ITD-negative AML, in both the first-line and R/R settings, in patients fit or unfit for intensive chemotherapy, including studies for quizartinib-based combination with other compounds such as decitabine and venetoclax. Future research should aim to further optimize the clinical value of quizartinib and explore its use in additional clinical settings, which could be achieved by testing quizartinib with other drugs, better characterization of the mechanisms of resistance, identification of the role of quizartinib as a maintenance therapy after allo-HCT, and investigating quizartinib in patients with FLT3-ITD-negative AML.

Cortes J 《Journal of Hematology & Oncology》

REGAL: galinpepimut-S vs. best available therapy as maintenance therapy for acute myeloid leukemia in second remission.

Jamy O ，Cicic D 《-》

Mutation- and MRD-informed treatments for transplant-ineligible patients.

The ongoing development of molecularly targeted therapies in addition to the new standard of care combination of azacitidine and venetoclax (AZA-VEN) has transformed the prognostic outlook for older, transplant-ineligible patients with acute myeloid leukemia (AML). While conventional treatments, such as standard anthracycline and cytarabine- based chemotherapy or hypomethylating agent (HMA) monotherapy, are associated with a generally poor prognosis in this patient population, the use of these novel regimens can result in long-lasting, durable remissions in select patient subgroups. Furthermore, the simultaneous discovery of resistance mechanisms to targeted therapies and AZA-VEN has enabled the identification of patient subgroups with inferior outcomes, leading to the development, of new risk-stratification models and clinical investigations incorporating targeted therapies using an HMA-VEN-based platform. Treatments inclusive of IDH1, IDH2, FLT3, and menin inhibitors combined with HMA-VEN have additionally demonstrated safety and high rates of efficacy in early-phase clinical trials, suggesting these regimens may further improve outcomes within select subgroups of patients with AML in the near future. Additional studies defining the prognostic role of measurable residual disease following VEN-based treatment have further advanced prognostication capabilities and increased the ability for close disease monitoring and early targeted intervention prior to morphologic relapse. This review summarizes these recent developments and their impact on the treatment and survival of transplant-ineligible patients living with AML.

Lachowiez CA ，DiNardo CD 《-》

Far Posterior Approach for Rib Fracture Fixation: Surgical Technique and Tips.

The present video article describes the far posterior or paraspinal approach to posterior rib fractures. This approach is utilized to optimize visualization intraoperatively in cases of far-posterior rib fractures. This technique is also muscle-sparing, and muscle-sparing posterolateral, axillary, and anterior approaches have been shown to return up to 95% of periscapular strength by 6 months postoperatively1. Like most fractures, the skin incision depends on the fracture position. The vertical incision is made either just medial to a line equidistant between the palpable spinous processes and medial scapular border or directly centered over the fracture line in this region. The incision and superficial dissection must be extended cranially and caudally, approximately 1 or 2 rib levels past the planned levels of instrumentation, in order to allow muscle elevation and soft-tissue retraction. Superficial dissection reveals the trapezius muscle, with its fibers coursing from inferomedial to superolateral caudal to the scapular spine, and generally coursing transversely above this level. The trapezius is split in line with its fibers (or elevated proximally at the caudal-most surface), and the underlying layer will depend on the location of the incision. The rhomboid minor muscle overlies ribs 1 and 2, the rhomboid major muscle overlies ribs 3 to 7, and the latissimus dorsi overlies the remaining rib levels. To avoid muscle transection, the underlying muscle is also split in line with its fibers. Next, the thoracolumbar fascia is encountered and sharply incised, revealing the erector spinae muscles, which comprise the spinalis thoracis, longissimus thoracis, and iliocostalis thoracis muscles. These muscles and their tendons must be sharply elevated from lateral to midline; electrocautery is useful for this because there is a robust blood supply in this region. Medially, while retracting the paraspinal musculature, visualization with this approach can extend to the head and neck of the rib, and even to the spine. Following deep dissection, the fractures are now visualized. During fracture reduction, it is critical to assess reduction of both the costovertebral joint and the costotransverse joint. With fractures closer to the spine, it is recommended to have at least 2 cm between the rib head and tubercle in order to allow 2 plate holes to be positioned on the neck of the rib; if comminution exists and plating onto the transverse process is needed, several screws are required here for stability as well. For appropriate stability if plating onto the spine is not required, a minimum of 3 locking screws on each side of the fracture are recommended. Contouring of the plates to match the curvature of the rib and to allow for proper apposition may be required with posterior rib fractures. Screws must be placed perpendicular to the rib surface. Following operative stabilization of the rib fractures, a layered closure is performed, and a soft dressing is applied. Nonoperative alternatives include non-opioid and opioid medications as well as corticosteroid injections for pain control. Supportive mechanical ventilation and physiotherapy breathing exercises can also be implemented as needed. Operative alternatives include open reduction and internal fixation utilizing conventional locking plates and screws. Rib fractures are often treated nonoperatively when nondisplaced because of the surrounding soft-tissue support2,3. According to Chest Wall Injury Society guidelines, contraindications to surgical fixation of rib fractures include patients requiring ongoing resuscitation; rib fractures involving ribs 1, 2, 11, or 12, which are relative contraindications; severe traumatic brain injury; and acute myocardial infarction. Patient age of <18 years is also a relative contraindication for the operative treatment of rib fractures. The current literature does not recommend surgical fixation in this age group because these fractures typically heal as the patient ages; however, fracture-dislocations may require the use of instrumentation to prevent displacement. Currently, the U.S. Food and Drug Administration does not approve most plating systems for patients <18 years old4. In certain cases, including those with substantial displacement, persistent respiratory distress, pain, or fracture nonunion, stabilization with open reduction and internal fixation may be appropriate5-7. In cases of flail chest injuries, surgery is often indicated6. Flail chest injuries have been noted in the literature to have an incidence of approximately 150 cases per 100,000 injuries and have been shown to carry a mortality rate of up to 33%8,9. Surgical treatment of rib fractures has been shown to be associated with a decreased hospital length of stay and mortality rate in patients with major trauma1. Expected outcomes of this procedure include low complication rates, decreased hospital and intensive care unit length of stay, and reduced mechanical ventilation time10,11. However, as with any procedure, there are also risks involved, including iatrogenic lung injury from long screws or an aortic or inferior vena cava injury with aggressive manipulation of displaced fractured fragments, especially on the left side of the body. During open reduction, there is also a risk of injuring the neurovascular bundle. Tanaka et al. demonstrated a significant reduction in the rate of postoperative pneumonia in their operative group (22%) compared with their nonoperative group (90%)12. Schuette et al. demonstrated a 23% rate of postoperative pneumonia, 0% mortality at 1 year, an average of 6.2 days in the intensive care unit, an average total hospital length of stay of 17.3 days, and an average total ventilator time of 4 days in the operative group10. Prins et al. reported a significantly lower incidence of pneumonia in operative (24%) versus nonoperative patients (47.3%; p = 0.033), as well as a significantly lower 30-day mortality rate (0% versus 17.7%; p = 0.018)3. This procedure utilizes a muscle-sparing technique, which has demonstrated successful results in the literature on the use of the posterolateral, axillary, and anterior approaches, returning up to 95% of periscapular strength, compared with the uninjured shoulder, by 6 months postoperatively1. The use of a muscle-sparing technique with the far-posterior approach represents a topic that requires further study in order to compare the results with the successful results previously shown with other approaches. The ipsilateral extremity can be prepared into the field to allow its intraoperative manipulation in order to achieve scapulothoracic motion and improved subscapular access.For costovertebral fracture-dislocations, the vertical incision line is made just medial to a line equidistant between the palpable spinous processes and medial scapular border.Lateral decubitus positioning can be utilized to allow for simultaneous access to fractures that extend more laterally and warrant a posterolateral approach; however, it is generally more difficult to access the fracture sites near the spine with this approach.This muscle-sparing technique is recommended to optimize postoperative periscapular strength, as previously demonstrated with other approaches.Incision and superficial dissection must be extended cranially and caudally approximately 1 or 2 rib levels past the planned levels of instrumentation in order to allow muscle elevation and soft-tissue retraction.To avoid muscle transection during surgical dissection, the underlying muscle is split in line with its fibers.During deep dissection, it can be difficult to delineate underlying muscles because these muscles have fibers that do not run in line with the trapezius, and some, like the rhomboid major, run nearly perpendicular to it.Electrocautery is useful while elevating the erector spinae muscles and tendons, as there is a robust blood supply in this region.The erector spinae muscle complex is relatively tight and adherent to the underlying ribs, which may make it difficult to achieve adequate visualization; therefore, at least 3 rib levels must be elevated to access a rib for reduction and instrumentation.Although internal rotation deformities are more common in this region, any external displacement of a fracture can lead to a muscle injury that can be utilized for access.During fracture reduction, it is critical to assess reduction of both the costovertebral joint and the costotransverse joint.Special attention must be given to contouring the implants because there are not any commercially available precontoured implants for this region at this time, and plating onto the spine remains an off-label use of any currently available implant.For the more challenging fracture patterns, the use of a right-angled power drill and screwdriver is recommended.Generally, the incision is utilized as previously described to provide access as far medial as the transverse process if needed. However, in cases in which this approach does not allow proper visualization with rib fracture-dislocations involving the posterior ribs or spine, a midline spinal incision can be utilized while working in combination with a spine surgeon.With fractures closer to the spine, it is recommended to have at least 2 cm between the rib head and tubercle in order to allow 2 plate holes to be positioned on the neck of the rib.If comminution exists and plating onto the transverse process is needed, several screws are required for stability.When measuring the length of screws to be placed in the transverse process, preoperative CT scans can be utilized. CT = computed tomographyCWIS = Chest Wall Injury SocietyIVC = inferior vena cava.

Manes TJ ，DeGenova DT ，Taylor BC ，Patel JN ... -  《-》