Inotuzumab ozogamicin versus FLAG-Ida in the treatment of relapsed or refractory B-cell acute lymphoblastic leukemia - real-world resource use data

Health Care Resource Utilization and Total Costs of Care for Adult Patients With Relapsed or Refractory Acute Lymphoblastic Leukemia in the United States: A Retrospective Claims Analysis

PURPOSE

Although immunotherapies such as blinatumomab and inotuzumab have led to improved outcomes, financial burden and health resource utilization (HRU) have increased for adult patients with relapsed or refractory B-cell acute lymphoblastic leukemia (R/R B-ALL). This study assessed real-world HRU and costs of care among adult patients with R/R B-ALL by line of therapy (LoT) in the United States.

METHODS

We selected patients from the MarketScanⓇ Database (January 1, 2016 through December 31, 2020) as follows: ≥1 claims of ALL-indicated first-line (1L) therapies, ≥1 diagnosis of ALL before the index date (1L initiation date), 6-month continuous enrollment before the index date, second-line (2L) therapy initiation, ≥18 years old at 2L, no clinical trial enrollment, no diagnosis of other forms of non-Hodgkin's lymphoma, and no claim for daratumumab or nelarabine during the study period. Outcome measures included claim-based time to next treatment (TTNT), all-cause and adverse event (AE)-related HRU, and all-cause and AE-related costs.

FINDINGS

The R/R B-ALL cohort (N = 203) was 60% male, median age of 41 years, and median Charlson Comorbidity Index score of 3.0. Mean (SD) follow-up was 17.8 (11.8) months. Of those who received 2L, 55.7% (113/203) required 3L, and 15% (30/203) initiated 4L+. Patients relapsed quickly, with a median TTNT of 170 days, 169 days, and 205 days for 2L, 3L, and 4L+, respectively. Hospitalization rates were high across each LoT (2L, 88%; 3L, 73%; 4L+, 73%), and the mean (SD) inpatient length of stay increased by LoT as follows: 8.6 (6.8) days for 2L, 10.6 (13.3) for 3L, and 11.6 (13.6) for 4L+. Mean (SD) overall costs were substantial within each LoT at $513,279 ($599,209), $340,419 ($333,555), and $390,327 ($332,068) for 2L, 3L, and 4L+, respectively. The mean (SD) overall/per-patient-per-month AE-related costs were $358,676 ($497,998) for 2L, $202,621 ($272,788) for 3L, and $210,539 ($267,814) for 4L+. Among those receiving blinatumomab or inotuzumab within each LoT, the mean (SD) total costs were $566,373 ($621,179), $498,070 ($376,260), and $512,908 ($159,525) for 2L, 3L, and 4L+, respectively.

IMPLICATIONS

These findings suggest that adult patients with R/R B-ALL relapse frequently with standard of care and incur a substantial HRU and cost burden with each LoT. Those treated with blinatumomab or inotuzumab incurred higher total costs within each LoT compared with the overall R/R B-ALL cohort. Alternative therapies with longer duration of remission are urgently needed, and HRU should be considered for future studies examining the optimal sequencing of therapy.

Cost-Effectiveness of Inotuzumab Ozogamicin Compared to Standard of Care Chemotherapy for Treating Relapsed or Refractory Acute Lymphoblastic Leukaemia Patients in Norway and Sweden

OBJECTIVE

The aim was to estimate the cost-effectiveness of inotuzumab ozogamicin (InO) versus standard of care chemotherapy (SoC) for adults with relapsed or refractory B cell acute lymphoblastic leukaemia (R/R ALL) in Sweden and Norway, and compare this to evaluations made by the health technology assessment (HTA) authorities Tandvårds- och läkemedelsförmånsverket (TLV) and the Norwegian Medicines Agency (NoMA).

MATERIALS AND METHODS

A partitioned survival model was developed to determine incremental cost-effectiveness ratios (ICERs) for InO versus SoC. Parametric survival models were fit to overall survival and progression-free survival Kaplan-Meier data from the INO-VATE ALL phase III trial. Two base cases were run using (1) Swedish and (2) Norwegian inputs (costs and discount rates). Core clinical inputs and utilities did not differ between countries. Analyses were then conducted to reflect the preferred assumptions of TLV and NoMA. Univariate and multivariate sensitivity analyses were performed.

RESULTS

The base case deterministic ICERs for InO versus SoC were €16,219/quality-adjusted life years (QALY) in Sweden (probabilistic €19,415) and €44,405/QALY in Norway (probabilistic €47,305). The ICERs using our model but applying the preferred assumptions of TLV or NoMA were €74,061/QALY (probabilistic €77,484) and €59,391/QALY (probabilistic €63,632), respectively. Differences between our base cases and the ICERs with TLV and NoMA settings were mainly explained by the exclusion of productivity costs and use of pooled post-haematopoietic stem-cell transplant (post-HSCT) survival in Sweden and use of higher HSCT costs in Norway. All ICERs remained below the approximated willingness-to-pay thresholds. The probability of InO being cost-effective ranged from 77 to 99% versus SoC.

CONCLUSIONS

InO can likely be considered cost-effective versus SoC under our and the HTA-preferred settings.