Hypomethylating agent (HMA) therapy use and survival in older adults with Refractory Anemia with Excess Blasts (RAEB) in the United States (USA): a large propensity score-matched population-based study†

Clinical Outcomes in Patients With Refractory Anemia With Excess Blasts (RAEB) Who Receive Hypomethylating Agents (HMAs)

BACKGROUND

We sought to understand the clinical effectiveness associated with use of hypomethylating agents (HMAs) azacitidine (AZA) and decitabine (DEC) for patients with refractory anemia with excess blasts (RAEB; an established proxy for higher-risk myelodysplastic syndromes/neoplasms) in contemporary and representative real-world settings.

PATIENTS AND METHODS

We used the Surveillance, Epidemiology and End Results (SEER)-Medicare database, a linkage of cancer registry and Medicare claims data, to identify patients aged ≥ 66 years diagnosed with RAEB, between 2009 and 2017 in the United States, and who received AZA or DEC as first-line therapy. Outcomes measured were overall survival (OS), event-free survival (EFS), and incidence of progression-related acute myeloid leukemia (AML).

RESULTS

Of 973 eligible patients, 738 (75.8%) received AZA and 235 (24.2%) received DEC; 6.4% received hematopoietic cell transplantation during follow-up. In the overall population, median OS was 13.9 months (95% confidence interval [CI]: 12.9-15.0), median EFS was 5.2 months (95% CI: 4.9-5.7), and 38.0% of patients progressed to AML. Incidences of AML progression and death were 25.6% and 29.9%, respectively, at Year 1, and 34.3% and 44.8%, respectively, at Year 2. There were no significant differences in clinical benefits between AZA and DEC.

CONCLUSION

Median OS with both HMAs remained significantly shorter than in the AZA-001 clinical trial, highlighting how patient outcomes vary between clinical and real-world settings. Further research is required to understand why these disparities exist.

Impact of preexisting autoimmune disease on myelodysplastic syndromes outcomes: a population analysis

Preexisting autoimmune disease affects between 10% and 30% of patients with myelodysplastic syndromes (MDS). Studies comparing outcomes in patients with MDS with and without autoimmune disease show discordant results. Using the Surveillance, Epidemiology, and End Results Medicare database, we conducted a population analysis to define the impact of autoimmunity on MDS outcomes. Cases were ascertained between 2007 and 2017 and claim algorithms used to identify autoimmune disease, demographic characteristics, comorbidity scores, MDS histology, transfusion burden, treatment with hypomethylating agents, and hematopoietic stem cell transplantation. Cox regression models estimated the impact on survival, and competing-risk regression models defined the effect on leukemic transformation. We analyzed 15 277 patients with MDS, including 2442 (16%) with preexisting autoimmune disease. The epidemiologic profile was distinctive in cases with preexisting autoimmunity, who were younger, were predominantly female, and had higher transfusion burden without difference in MDS histologic distribution. Autoimmune disease was associated with 11% decreased risk of death (hazard ratio [HR], 0.89; 95% confidence interval [CI], 0.85-0.94; P < .001). The effect on risk of leukemic transformation differed based on MDS histology. In low-risk MDS histologies, autoimmunity was associated with a 1.9-fold increased risk of leukemia (HR, 1.87; 95% CI, 1.17-2.99; P = .008), whereas no significant effect was seen in other groups. These results suggest that autoimmune disease affects survival in MDS and is associated with decreased mortality. The survival effect was evident in low-risk histologies despite higher risk of progression to leukemia. This could represent inflammation-driven hematopoiesis, simultaneously favoring less aggressive phenotypes and clonal expansion, which warrants further investigation.

Are We Ready For "Triplet" Therapy in Higher-Risk MDS?

Higher-risk Myelodysplastic Syndromes/Neoplasms (MDS) represent an ongoing therapeutic challenge, with few effective therapies, many of which may have limited use in this older patient population often with considerations around comorbidities. Outside of transplant, azacitidine and decitabine remain the only disease-modifying therapies, and are palliative in nature. Recent interest has grown in extending combination chemotherapies used to treat acute myeloid leukemia (AML) to patients with MDS, including novel combination chemotherapy "doublets" and "triplets." In this review, we discuss considerations around combination chemotherapy in MDS, specifically as relates to study design, appropriate endpoints, supportive considerations, and how to integrate these into the current treatment paradigm. New therapies in MDS are desperately needed but also require considerations particular to this unique patient population.

Decitabine/Cedazuridine in the Management of Myelodysplastic Syndrome and Chronic Myelomonocytic Leukemia in Canada

The management of myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) is limited and remains an unmet need. Decitabine/cedazuridine (DEC-C, ASTX727) is Canada's first and only approved oral hypomethylating agent for MDS and CMML. We characterized the real-world use of DEC-C through a Canadian compassionate use program. Demographic and clinical data from 769 patients enrolled in Taiho Pharma Canada's Patient Support Program were collected and analyzed. These patients represent a collection period from 10 November 2020 to 31 August 2022 with a median age of 76 years. Among 651 patients who started DEC-C, the median treatment duration was 4.2 cycles. The median overall and progression-free survival were 21.6 and 10.7 months, respectively. Among 427 patients who discontinued treatment, the majority (69.5%) stopped due to death (n = 164) or disease progression (n = 133). Multivariable cox regression showed that age, province of residence, blast counts, antibiotic prophylaxis, and number of dose reductions and delays were not significantly associated with overall and progression-free survival. DEC-C is a promising alternative to parenteral hypomethylating agent therapy, and it likely addresses an important unmet need for effective and convenient therapies in this setting.

Impact of Hypomethylating Agent Use on Hospital and Emergency Room Visits, and Predictors of Early Discontinuation in Patients With Higher-Risk Myelodysplastic Syndromes

BACKGROUND

Previous analyses using the SEER-Medicare database have reported substantial underutilization of hypomethylating agents (HMAs) among patients with higher-risk myelodysplastic syndromes (MDS), and an association between poor HMA persistence and high economic burden. We aimed to compare rates of hospitalizations and emergency room (ER) visits among patients with higher-risk MDS according to use or non-use of HMA therapy, and to explore factors associated with early discontinuation of HMA therapy.

PATIENTS AND METHODS

We used the 2010-2016 SEER-Medicare database to identify patients aged ≥66 years with a new diagnosis of refractory anemia with excess blasts (RAEB; a surrogate for higher-risk MDS) between 2011 and 2015. New hospitalizations and ER visits during the 12 months following MDS diagnosis were determined. Treatment discontinuation was defined as stopping HMA therapy before 4 cycles.

RESULTS

Overall, 664 (55.8%) patients were HMA users and 526 (44.2%) non-users. Non-users had more hospitalizations (mean 0.47 vs. 0.30, P < .001) and ER visits (mean 0.69 vs. 0.41, P = .005) per month than HMA users. Among HMA users, 193 (29.1%) discontinued HMA therapy before 4 cycles, and 91 (47.2%) of these after 1 cycle. Older age and poor performance status were associated with higher risk of HMA discontinuation.

CONCLUSION

An increased rate of hospitalizations and ER visits occurred in HMA non-users vs. HMA users. Approximately one-third of patients discontinued HMA therapy early. Predictors of discontinuation included older age and poor performance status. Novel approaches are needed to improve utilization and persistence with HMA therapy and associated outcomes, particularly among these higher-risk groups.

A Randomized Phase 2 Trial of Azacitidine ± Durvalumab as First-line Therapy for Higher-Risk Myelodysplastic Syndromes

This is the first reported randomized trial of immune checkpoint inhibitor therapy in HR-MDS.

Azacitidine combined with the PD-L1 inhibitor durvalumab was feasible but did not improve outcomes over azacitidine alone.

Azacitidine-mediated hypomethylation promotes tumor cell immune recognition but may increase the expression of inhibitory immune checkpoint molecules. We conducted the first randomized phase 2 study of azacitidine plus the immune checkpoint inhibitor durvalumab vs azacitidine monotherapy as first-line treatment for higher-risk myelodysplastic syndromes (HR-MDS). In all, 84 patients received 75 mg/m² subcutaneous azacitidine (days 1-7 every 4 weeks) combined with 1500 mg intravenous durvalumab on day 1 every 4 weeks (Arm A) for at least 6 cycles or 75 mg/m² subcutaneous azacitidine alone (days 1-7 every 4 weeks) for at least 6 cycles (Arm B). After a median follow-up of 15.25 months, 8 patients in Arm A and 6 in Arm B remained on treatment. Patients in Arm A received a median of 7.9 treatment cycles and those in Arm B received a median of 7.0 treatment cycles with 73.7% and 65.9%, respectively, completing ≥4 cycles. The overall response rate (primary end point) was 61.9% in Arm A (26 of 42) and 47.6% in Arm B (20 of 42; P = .18), and median overall survival was 11.6 months (95% confidence interval, 9.5 months to not evaluable) vs 16.7 months (95% confidence interval, 9.8-23.5 months; P = .74). Durvalumab-related adverse events (AEs) were reported by 71.1% of patients; azacitidine-related AEs were reported by 82% (Arm A) and 81% (Arm B). Grade 3 or 4 hematologic AEs were reported in 89.5% (Arm A) vs 68.3% (Arm B) of patients. Patients with TP53 mutations tended to have a worse response than patients without these mutations. Azacitidine increased programmed cell death ligand 1 (PD-L1 [CD274]) surface expression on bone marrow granulocytes and monocytes, but not blasts, in both arms. In summary, combining azacitidine with durvalumab in patients with HR-MDS was feasible but with more toxicities and without significant improvement in clinical outcomes over azacitidine alone. This trial was registered at www.clinicaltrials.gov as #NCT02775903.

Oral hypomethylating agents: beyond convenience in MDS

Oral hypomethylating agents (HMAs) represent a substantial potential boon for patients with myelodysplastic syndrome (MDS) who have previously required between 5 and 7 visits per month to an infusion clinic to receive therapy. For patients who respond to treatment, ongoing monthly maintenance visits represent a considerable burden to quality of life, and for those who are early in therapy, these sequential visits may tax transportation and financial resources that would be optimally distributed over the treatment cycle to facilitate transfusion support. The availability of oral HMAs may support the optimal application of these agents by contributing to adherence and lessening the burden of therapy, potentially encouraging patients to stay on longer-term treatment. Distinct pharmacokinetic profiles for the recently approved oral HMAs (oral azacitidine and decitabine-cedazuridine) result in differential toxicity profiles and have prompted their clinical trial development in lower- and higher-risk MDS, respectively.

Real-world use and outcomes of hypomethylating agent therapy in higher-risk myelodysplastic syndromes: why are we not achieving the promise of clinical trials?

Myelodysplastic syndromes are hematological malignancies characterized by ineffective hematopoiesis and a high risk of progression to acute myeloid leukemia. Hypomethylating agents (HMAs), azacitidine and decitabine, are standard of care therapy for higher-risk myelodysplastic syndromes. However, outcomes reported for real-world studies fall short of those achieved in clinical trials. We conducted a targeted literature review exploring real-world utilization, persistence and outcomes with intravenous and subcutaneous HMA therapies to better understand barriers to achieving optimal outcomes in clinical practice. The potential benefits of oral HMA therapy were also explored. Underutilization and poor persistence with HMA therapy are associated with suboptimal outcomes, highlighting the need for approaches to improve utilization and persistence, so that patients achieve the optimum benefit from HMA therapy.

Management of the Older Patient with Myelodysplastic Syndrome

No two diagnoses of myelodysplastic syndrome are genuinely alike, owing to differing and dynamic mutational topography and epigenetic aberrancy. Consequently, no two patients with myelodysplastic syndrome are identical and disease-specific and patient-specific factors are considered in formulating the optimal treatment, which includes few that are disease modifying. Age itself should not be an absolute contraindication to therapy, including intensive therapy such as allogeneic hematopoietic stem cell transplantation, which is the only curative therapy. However, age associates with an increased prevalence of frailty and comorbidities that must be considered and may preclude a path to cure. Palliative therapies are the mainstay for many patients with myelodysplastic syndrome, which is a disease of older adults with the majority of patients diagnosed at age ≥ 75 years. The older patient requires heightened attention to end organ function/reserve and drug-drug interactions as well as insurance, income, cost, and socioeconomic and psychosocial issues that influence management. Many prior studies have included relatively younger populations or have not specifically performed high-quality subgroup analyses of older patients. In this review, we discuss the available standard-of-care therapies for myelodysplastic syndrome as they specifically relate to the older population and assess the emerging therapeutics that may further the pursuit for personalized treatment and improve both the outcomes and quality of life of the older patient with myelodysplastic syndrome.

Clinical outcomes of older patients with AML receiving hypomethylating agents: a large population-based study in the United States

The hypomethylating agents (HMAs) azacitidine and decitabine have been the de facto standard of care for patients with acute myeloid leukemia (AML) who are unfit for intensive therapy. Using the Surveillance, Epidemiology, and End Results-Medicare linked database, we identified 2263 older adults (age ≥66 years) diagnosed with AML during 2005-2015 who received a first-line HMA; 1154 (51%) received azacitidine, and 1109 (49%) received decitabine. Median survival from diagnosis was 7.1 and 8.2 months (P < .01) for azacitidine- and decitabine-treated patients, respectively. Mortality risk was higher with azacitidine vs decitabine (hazard ratio [HR], 1.11; 95% confidence interval [CI], 1.01-1.21; P = .02). The findings were similar when evaluating only patients completing ≥4 cycles (42% of patients treated with either azacitidine or decitabine). These findings lost significance when evaluating those completing a standard 7-day schedule of azacitidine (34%) vs 5-day schedule for decitabine (66%) (HR, 0.95; 95% CI, 0.83-1.08; P = .43). Red blood cell (RBC) transfusion independence (TI) was achieved in one-third of patients with no difference between the 2 HMAs. In conclusion, the majority of older AML patients did not receive the minimum of 4 cycles of HMA often needed to elicit clinical benefit. We observed no clinically meaningful differences between azacitidine- and decitabine-treated patients in their achievement of RBC TI or survival.

Direct Medical Costs Associated With Treatment Nonpersistence in Patients With Higher-Risk Myelodysplastic Syndromes Receiving Hypomethylating Agents: A Large Retrospective Cohort Analysis

BACKGROUND

Suboptimal use of hypomethylating agents (HMAs) among higher-risk myelodysplastic syndrome (HR-MDS) patients can translate into worse health outcomes and economic burden. We estimated the direct medical costs associated with HMA treatment nonpersistence among HR-MDS patients.

PATIENTS AND METHODS

Using the Surveillance, Epidemiology, and End Results-Medicare linked database, a retrospective cohort of patients diagnosed with refractory anemia with excess blasts (RAEB), a diagnosis that substantially overlaps with HR-MDS, between January 2011 and December 2015 was analyzed. Patients who had ≥ 1 year of continuous Medicare enrollment before diagnosis and who did not receive stem cell transplant or lenalidomide in the follow-up period were included. Patients receiving HMAs were stratified into HMA persistent (≥4 HMA cycles) and HMA nonpersistent (<4 cycles or a gap of ≥ 90 days between cycles) groups. Healthcare resource use and costs during the follow-up period were reported descriptively as total and per patient per month (PPPM). Weighted generalized linear models (GLM) were used to compare estimated healthcare resource use and costs between HMA groups.

RESULTS

Among the 664 patients with RAEB, 295 (44.4%) were HMA nonpersistent and 369 (55.6%) HMA persistent. On the basis of weighted GLM analysis, the HMA nonpersistent group incurred significantly (P < .05) higher total PPPM costs compared to the HMA persistent group ($18,039 vs. $13,893), particularly for hospitalization ($3,375 vs. $2,131), and emergency room ($5,517 vs. $2,867) costs.

CONCLUSION

There is a substantial economic burden associated with early discontinuation of guideline-recommended HMA therapy in RAEB patients. The study findings necessitate closer care management in this population in order to improve outcomes and reduce healthcare spending.

Under-use of Hypomethylating Agents in Patients With Higher-risk Myelodysplastic Syndrome in the United States: A Large Population-based Analysis

BACKGROUND

Recent data suggest significant underutilization of hypomethylating agents (HMAs) that are recommended treatments for patients with myelodysplastic syndromes (MDS) with refractory anemia with excess blasts (RAEB). The study objective was to assess the degree of HMA use and predictors of HMA underuse in this population.

PATIENTS AND METHODS

This was a retrospective study including patients diagnosed with the RAEB form of MDS between January 2011 and December 2015 using the Surveillance, Epidemiology, and End Results-Medicare linked database. Patients were excluded if they had < 1 year of continuous enrollment before diagnosis or received stem cell transplant or lenalidomide during the follow-up period. HMA non-peristence was defined as use of < 4 cycles (3-10 HMA days/28 days) of HMAs or a gap of ≥ 90 days between consecutive cycles. Patients were characterized as HMA never-users, HMA-persistent users, and HMA-non-persistent users. Descriptive statistics were used to summarize patient characteristics. Multivariable logistic regression was used to assess predictors of HMA underuse and persistence.

RESULTS

Of the 1190 patients, 526 (44%) were never-users, 295 (25%) were non-persistent users, and 369 (31%) were persistent users. Age at diagnosis (eg, 66-70 years vs. ≥ 80 years; odds ratio [OR], 2.36; 95% confidence interval [CI], 1.56-3.56), marital status (single vs. married; OR, 0.67; 95% CI, 0.51-0.89), National Cancer Institute comorbidity index (≥ 3 vs. 0-1; OR, 0.62; 95% CI, 0.46-0.83), and performance status (poor vs. good; OR, 0.67; 95% CI, 0.51-0.87) were significantly associated with HMA underuse.

CONCLUSION

Several demographic and clinical factors were associated with underuse of HMAs. There is need for a better understanding of suboptimal HMA use and its relationship with clinical response.