Approximately 20% of patients with
-mutant myelodysplastic syndromes (MDS) achieve complete remission (CR) with hypomethylating agents. Eprenetapopt (APR-246) is a novel, first-in-class, small ...molecule that restores wild-type p53 functions in
-mutant cells.
This was a phase Ib/II study to determine the safety, recommended phase II dose, and efficacy of eprenetapopt administered in combination with azacitidine in patients with
-mutant MDS or acute myeloid leukemia (AML) with 20%-30% marrow blasts (ClinicalTrials.gov identifier: NCT03072043).
Fifty-five patients (40 MDS, 11 AML, and four MDS/myeloproliferative neoplasms) with at least one
mutation were treated. The overall response rate was 71% with 44% achieving CR. Of patients with MDS, 73% (n = 29) responded with 50% (n = 20) achieving CR and 58% (23/40) a cytogenetic response. The overall response rate and CR rate for patients with AML was 64% (n = 7) and 36% (n = 4), respectively. Patients with only
mutations by next-generation sequencing had higher rates of CR (69%
25%;
= .006). Responding patients had significant reductions in
variant allele frequency and p53 expression by immunohistochemistry, with 21 (38%) achieving complete molecular remission (variant allele frequency < 5%). Median overall survival was 10.8 months with significant improvement in responding versus nonresponding patients by landmark analysis (14.6
7.5 months;
= .0005). Overall, 19/55 (35%) patients underwent allogeneic hematopoietic stem-cell transplant, with a median overall survival of 14.7 months. Adverse events were similar to those reported for azacitidine or eprenetapopt monotherapy, with the most common grade ≥ 3 adverse events being febrile neutropenia (33%), leukopenia (29%), and neutropenia (29%).
Combination treatment with eprenetapopt and azacitidine is well-tolerated yielding high rates of clinical response and molecular remissions in patients with
-mutant MDS and oligoblastic AML.
Blastic plasmacytoid dendritic-cell neoplasm (BPDCN) is an aggressive hematologic cancer that is caused by transformed plasmacytoid dendritic cells that overexpress interleukin-3 receptor subunit ...alpha (IL3RA or CD123). Tagraxofusp (SL-401) is a CD123-directed cytotoxin consisting of human interleukin-3 fused to truncated diphtheria toxin.
In this open-label, multicohort study, we assigned 47 patients with untreated or relapsed BPDCN to receive an intravenous infusion of tagraxofusp at a dose of 7 μg or 12 μg per kilogram of body weight on days 1 to 5 of each 21-day cycle. Treatment continued until disease progression or unacceptable toxic effects. The primary outcome was the combined rate of complete response and clinical complete response among patients who had not received previous treatment for BPDCN. A secondary outcome was the duration of response.
Of the 47 patients, 32 were receiving tagraxofusp as first-line treatment and 15 had received previous treatment. The median age of the patients was 70 years (range, 22 to 84). Among the 29 previously untreated patients who received tagraxofusp at a dose of 12 μg per kilogram, the primary outcome occurred in 21 (72%), and the overall response rate was 90%; of these patients, 45% went on to undergo stem-cell transplantation. Survival rates at 18 and 24 months were 59% and 52%, respectively. Among the 15 previously treated patients, the response rate was 67%, and the median overall survival was 8.5 months. The most common adverse events were increased levels of alanine aminotransferase (64%) and aspartate aminotransferase (60%), hypoalbuminemia (55%), peripheral edema (51%), and thrombocytopenia (49%). Capillary leak syndrome was reported in 19% of the patients and was associated with one death in each of the dose subgroups.
In adult patients with untreated or relapsed BPDCN, the use of tagraxofusp led to clinical responses. Serious adverse events included capillary leak syndrome; hepatic dysfunction and thrombocytopenia were common. (Funded by Stemline Therapeutics and the Leukemia and Lymphoma Society Therapy Acceleration Program; ClinicalTrials.gov number, NCT02113982.).
JCO
Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive myeloid malignancy. We report long-term results, including data from the continued access phase, of the largest prospective ...BPDCN trial evaluating the CD123-targeted therapy tagraxofusp (TAG) in adults with treatment-naive and relapsed/refractory BPDCN. The primary outcome was complete response (CR) + clinical CR (CRc: CR with residual skin abnormality not indicative of active disease). Eighty-four (65 treatment-naive and 19 relapsed/refractory) of 89 patients received TAG 12 μg/kg once daily; the median follow-up was 34.0 months. For treatment-naive patients, the overall response rate was 75%; 57% achieved CR + CRc. The median time to remission was 39 (range, 14-131) days, and the median CR + CRc duration was 24.9 (95% CI, 3.8 to not reached) months. Nineteen patients (51%) with CR + CRc were bridged to stem-cell transplant, with a median CR + CRc duration of 22.2 (range, 1.5-57.4) months. Most common adverse events were increased alanine (64%) or aspartate (60%) aminotransferase and hypoalbuminemia (51%); most occurred in cycle 1 and were transient. Capillary leak syndrome occurred in 21% of patients (grade ≥ 3: 7%). In first-line patients with BPDCN, TAG monotherapy resulted in high and durable responses, allowing many to bridge to stem-cell transplant. TAG was generally well-tolerated with a predictable and manageable safety profile.
The implementation of next-generation sequencing (NGS) has influenced diagnostic, prognostic, and therapeutic decisions in myeloid malignancies. However, the clinical relevance of serial molecular ...annotation in patients with myelodysplastic syndrome (MDS) undergoing active treatment is unknown. MDS or secondary acute myeloid leukemia (sAML) patients who had at least two NGS assessments were identified. Outcomes according to mutation clearance (NGS-) on serial assessment were investigated. Univariate and multivariate Cox regression models were used to evaluate the prognostic impact of NGS trajectory on overall survival (OS). A total of 157 patients (MDS n = 95; sAML n = 52; CMML n = 10) were identified, with 93% of patients receiving treatment between NGS assessments. Magnitude of VAF delta from baseline was significantly associated with quality of response to treatment. Patients achieving NGS- had significantly improved OS compared to patients with mutation persistence (median OS not reached vs. 18.5 months; P = 0.002), which was confirmed in multivariate analysis (HR,0.14; 95%CI = 0.03-0.56; P = 0.0064). Serial TP53 VAF evaluation predicts outcomes with TP53 clearance representing an independent covariate for superior OS (HR,0.22; 95%CI = 0.05-0.99; P = 0.048). Collectively, our study highlights the clinical value of serial NGS during treatment and warrants prospective validation of NGS negativity as a biomarker for treatment outcome.
Background
Genomic landscape of extramedullary acute myeloid leukemia (EM‐AML), including myeloid sarcoma (MS) and leukemia cutis (LC), is not well characterized. The potential utility of ...next‐generation sequencing (NGS) using EM tissue is not established.
Methods
In this multicenter retrospective study, clinical and NGS data were collected on patients with EM‐AML. All statistical analyses were performed in SPSS Statistics (v 26).
Results
Our study included 58 patients with EM‐AML. The median age at diagnosis was 62 years; 59% of patients had MS and 33% had LC. EM‐AML was isolated (i.e., without blood or marrow involvement) in 31% and was first noted at relapse in 60% of patients. Median overall survival in our cohort was 18.2 months overall, with 19.1 months and 11.6 months in the newly diagnosed and the relapsed/refractory patients, respectively. At least one targetable or potentially targetable alteration was present in 52% of patients with EM‐site NGS, with 26% IDH1, 21% NPM1, 11% IDH2, 6% FLT3, and 13% KMT2A‐PTD. Mutations in IDH1 were significantly more prevalent on NGS from EM tissue than non‐EM (blood or marrow) samples (26% vs. 3%; p = .030). Three of four patients treated with IDH inhibitors based on EM‐site NGS experienced a complete response.
Conclusions
Targetable mutations are frequent in EM‐AML and EM‐site NGS is warranted for selecting potential targeted therapies for patients with EM‐AML.
Next‐generation sequencing (NGS) on extramedullary (EM) tissue revealed at least one potentially targetable alteration in 52% of patients with EM acute myeloid leukemia treatment with IDH inhibitors led to complete response in three of four patients with IDH1 or IDH2 mutations identified on EM‐site NGS.
Background
Thrombocytopenia in patients with myelofibrosis (MF) is prognostically detrimental and poses a therapeutic challenge. MF patients with thrombocytopenia are considered high‐risk by most ...prognostic models and their distinct phenotype has given rise to the emerging concept of cytopenic MF. Yet, the mechanisms underlying thrombocytopenia in MF are poorly understood.
Methods
This study aimed to highlight the genetic mechanisms driving low platelet counts in treatment‐naive MF patients, establish their phenotypic correlates, and assess prognostic factors specific to this group of patients.
Results
The authors found that most patients presenting with low platelets had a clear thrombocytopenia‐specific genetic abnormality involving a U2AF1 Q157 mutation, deletion 20q, molecular complexity (three or more mutations), or high‐risk karyotype. Etiologic clustering did not correlate with prognosis; however, thrombocytopenic patients were found to have unique prognostic variables including low serum albumin and mutations of SRSF2 and TP53. This led to the proposal of a prognostic model (SRSF2, albumin, TP53 score) that stratifies thrombocytopenic patients as low, intermediate, or high‐risk with corresponding median survivals of 93.5, 29.5, and 7.2 months, respectively.
Conclusions
This study demonstrates that thrombocytopenia in MF is driven by different genetic mechanisms and is not uniformly high‐risk. As novel agents with improved hematologic safety profiles enter the treatment landscape, thoughtful, risk‐adapted therapeutic decisions will be required for MF patients with thrombocytopenia.
Lay Summary
A significant minority of patients with myelofibrosis (MF) present with low platelets.
Historically, these patients have been viewed as having “high‐risk” disease, but this may not be uniformly true.
Our study shows that there are various different causes for low platelets in MF, some of which represent high‐risk disease whereas others do not.
Additionally, our study shows that genetic mutations affecting the genes SRSF2 and TP53 are uniquely problematic in this group, as is a low serum albumin level.
This study helps to risk‐stratify MF patients with thrombocytopenia, thereby providing more information to guide informed and individualized treatment decisions.
Cytopenic myelofibrosis (MF) is emerging as a distinct phenotypic entity that poses unique therapeutic challenges; however, little is known about the various causes of thrombocytopenia in MF and factors that influences prognosis in this subgroup. With the recent and upcoming approval of new, less myelosuppressive treatment options, it will be vital to understand how to risk stratify thrombocytopenic MF patients in an effort to individualize therapy.
Pivekimab sunirine (IMGN632) is a first-in-class antibody–drug conjugate comprising a high-affinity CD123 antibody, cleavable linker, and novel indolinobenzodiazepine pseudodimer payload. CD123 is ...overexpressed in several haematological malignancies, including acute myeloid leukaemia. We present clinical data on pivekimab sunirine in relapsed or refractory acute myeloid leukaemia.
This first-in-human, phase 1/2 dose-escalation and dose-expansion study enrolled participants aged 18 years or older at nine hospitals in France, Italy, Spain, and the USA with CD123+ haematological malignancies (Eastern Cooperative Oncology Group performance status of 0–1); participants reported here were in a cohort of participants with acute myeloid leukaemia who were refractory to or had relapsed on one or more previous treatments for acute myeloid leukaemia. The 3 + 3 dose-escalation phase evaluated two dosing schedules: schedule A (once every 3 weeks, on day 1 of a 3-week cycle) and fractionated schedule B (days 1, 4, and 8 of a 3-week cycle). The dose-expansion phase evaluated two cohorts: one cohort given 0·045 mg/kg of bodyweight (schedule A) and one cohort given 0·090 mg/kg of bodyweight (schedule A). The primary endpoints were the maximum tolerated dose and the recommended phase 2 dose. Antileukaemia activity (overall response and a composite complete remission assessment) was a secondary endpoint. The study is ongoing and registered with ClinicalTrials.gov, NCT03386513.
Between Dec 29, 2017, and May 27, 2020, 91 participants were enrolled (schedule A, n=68; schedule B, n=23). 30 (44%) of schedule A participants were female and 38 (56%) were male; 60 (88%) were White, six (9%) were Black or African American, and two (3%) were other races. Pivekimab sunirine at doses of 0·015 mg/kg to 0·450 mg/kg in schedule A was administered in six escalating doses with no maximum tolerated dose defined; three dose-limiting toxicities were observed (reversible veno-occlusive disease; 0·180 mg/kg, n=1 and 0·450 mg/kg, n=1; and neutropenia; 0·300 mg/kg, n=1). Schedule B was not pursued further on the basis of comparative safety and antileukaemia findings with schedule A. The recommended phase 2 dose was selected as 0·045 mg/kg once every 3 weeks. At the recommended phase 2 dose (n=29), the most common grade 3 or worse treatment-related adverse events were febrile neutropenia (three 10%), infusion-related reactions (two 7%), and anaemia (two 7%). Treatment-related serious adverse events occurring in 5% or more of participants treated at the recommended phase 2 dose were febrile neutropenia (two 7%) and infusion-related reactions (two 7%). Among 68 participants who received schedule A, one death (1%) was considered to be treatment-related (cause unknown; 0·300 mg/kg cohort). At the recommended phase 2 dose, the overall response rate was 21% (95% CI 8–40; six of 29) and the composite complete remission rate was 17% (95% CI 6–36; five of 29).
Pivekimab sunirine showed single-agent activity across multiple doses, with a recommended phase 2 dose of 0·045 mg/kg once every 3 weeks. These findings led to a phase 1b/2 study of pivekimab sunirine plus azacitidine and venetoclax in patients with CD123-positive acute myeloid leukaemia.
ImmunoGen.
The FDA has an accelerated approval program for drugs that have been identified as promising treatments for serious conditions when the available data suggest that the benefits outweigh the ...foreseeable risks. All of the currently available treatment options for chronic myeloid leukemia (CML) initially went through the accelerated approval program. Here, a group of academic CML experts, patient panelists, and members from the FDA convened to discuss the utility of the accelerated approval program as it pertains to CML, and the utility of this program in future drug development in this disease. The results of that discussion are summarized here.
•Glasdegib in HMA-refractory MDS and CMML has limited single-agent activity.•56% of heavily pretreated, primarily high-risk MDS patients had stable disease after glasdegib administration.•Stable ...disease or better was an independent covariate for improved overall survival.•Results support investigation of glasdegib in novel drug combinations.
Hypomethylating agent (HMA) failure myelodysplastic syndrome (MDS) patients have poor outcomes and urgent need for novel therapies. Hedgehog pathway signaling upregulation plays a central role in myeloid neoplasm pathogenesis and leukemia stem cell survival. We evaluated the efficacy and safety of the smoothened inhibitor glasdegib in HMA-failure MDS (n = 35, median age 73 years). According to the International Prognostic Scoring System and the MD Anderson Global Risk Model, 54% and 77% had higher risk disease, respectively. Overall response was 6% (n = 2), and best response was marrow complete remission with hematologic improvement in both patients. Median OS and median follow-up were 10.4 and 42.8 months, respectively. Drug response/stable disease (SD) resulted in better OS than treatment failure (20.6 95% CI, 10.4- vs 3.9 months 95% CI, 0.7–9.1; P< .0001). Response/SD was confirmed to be an independent covariate for improved OS (P < .0001). Grade 3 or higher infections occurred in 11% of patients (n = 4); non-hematologic toxicities were rare. Early mortality (< 30 days) occurred in 11% of patients (n = 4). Glasdegib was well tolerated among HMA-failure MDS patients, although single-agent activity was limited. SD or better resulted in notably superior OS. These results support further investigation of glasdegib, potentially in novel drug combinations, in MDS patients.
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