Epidemiology and Real-World Treatment of Chronic Graft-Versus-Host Disease Post Allogeneic Hematopoietic Cell Transplantation: A US Claims Analysis

Background

Chronic Graft-Versus-Host Disease (cGVHD) is a complication of hematopoietic cell transplantation (HCT). While the clinical outcomes of cGVHD are well documented, few studies have assessed its treatment practices in the real-world. The objectives of this study are to quantify the prevalence of cGVHD, to examine provider prescribing patterns, and to evaluate the healthcare cost and resource utilization (HCRU) in a real-world US cGVHD population.

Methods

This study analyzed de-identified claims from the Medicare FFS 5% sample for beneficiaries enrolled from 2013-2016 and Pharmetrics commercial 2013-2018 databases to identify cGVHD in allogenic HCT patients. cGVHD was identified based on ICD-9/10 diagnosis codes for cGVHD or unspecified GVHD with a first diagnosis >180 days post HCT, or subsequent unspecified GVHD diagnosis >12 months post index diagnosis. Chronic GVHD prevalence was estimated by calculating age-adjusted prevalence rates within the Medicare and Pharmetrics sample populations and applying rates to the total US patient subpopulations as determined by CMS and Census data. Prevalence estimates were based on the last complete year of both Medicare FFS and Pharmetrics data (2016). Longitudinal and Line of Therapy (LOT) analyses were based on data from 2013-2018. A new LOT was defined as starting with the addition of systemic therapy to a patient's cGVHD regimen, regardless of prior lines of therapy or prior treatment. Treatments that stopped and restarted within 60 days were considered continuous treatment. Healthcare costs were calculated by adding the inpatient, outpatient, and pharmacy insurer and beneficiary paid amounts for the commercially insured population. Total HCRU was assessed using the number of inpatient and outpatient visits following the initial cGVHD diagnosis.

Results

In 2016, the projected prevalence of cGVHD in the US based on the Medicare FFS and Pharmetrics commercial databases was 14,017 individual patients. Within 3 years post allogeneic HCT, 42% of patients developed cGVHD; 66% of cGVHD patients had a prior diagnosis of acute GVHD. The majority of cGVHD patients received at least one systemic therapy; 71% and 47% of cGVHD patients progressed to a second and third LOT, respectively (Table 1). Of patients that received a second and third LOT, the average time from diagnosis to the second and third LOT was approximately 7 months and 10 months, respectively. Over 80% of cGVHD patients received systemic corticosteroid therapy for the treatment of cGVHD within 12 months post diagnosis, and 41% of cGVHD patients were receiving a corticosteroid within the 30 days prior to diagnosis. Within the 12 months post cGVHD diagnosis, most patients received a corticosteroid or a corticosteroid combination as a first LOT (57%), which decreased slightly as patients progressed to second and third line of therapy (49% and 48%, respectively). A total of 25 unique therapeutic agents and over 150 combinations were used in second and third LOT. While newer agents, such as ibrutinib and ruxolitinib, are continuing to increase in utilization among cGVHD patients, these therapies are only used among 1% (ibrutinib) and 1-3% (ruxolitinib) of patients through their first three lines of therapy in the patients captured in Pharmetrics commercial database through June 2018. In the 12 months post diagnosis, cGVHD patients had an average of 21.0 GVHD-related inpatient and outpatient visits (2.8 inpatient and 18.2 outpatient visits). In 2016 the average total annual cost per commercially insured cGVHD patient was $291,357.

Conclusion

A significant proportion of allogenic HCT patients continue to develop cGVHD, and despite advances in the understanding of cGVHD, corticosteroids remain the mainstay of therapy. However, most cGVHD patients are not adequately managed with first line corticosteroids, and many patients are cycling through several therapies, likely in part due to lack of efficacy and toxicity associated with currently available treatments. Real-world utilization of systemic therapies is highly variable, particularly for patients who progress beyond the first LOT, which highlights the need for evidence-based treatment approaches. cGVHD is a highly burdensome complication of allogenic HCT, and safer, more effective treatments are needed as many patients are not currently well managed on available therapies.

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