For sickle cell disease (SCD), hydroxyurea is an established treatment. Despite this, hydroxyurea remains underutilized.
New disease-modifying treatments (DMTs), namely, crizanlizumab, L-glutamine, and voxelotor, have recently been approved. A new JAMA Network Open study delved deeper into understanding the uptake of these DMTs in the context of current treatment strategies.
Study: Use of Disease-Modifying Treatments in Patients With Sickle Cell Disease. Image Credit: angellodeco/Shutterstock.com
Background
SCD is a red blood cell disorder that can cause extensive morbidity and mortality. Prior to 2017, the sole DMT to treat SCD was hydroxyurea, which was seen to diminish rates of vaso-occlusive crises (VOCs) by 44%.
New DMTs, i.e., crizanlizumab, L-glutamine, and voxelotor, have recently been approved. Limited existing evidence suggests that these new-world DMTs can also effectively reduce VOCs and improve the clinical course of SCD.
Despite the documented efficacy, DMTs are underused. One reason could be that the existing literature evaluating DMT uses some limitations. This research often predates the approval of new DMTs and often focuses on a single DMT outcome.
Another issue with existing research is that it often studies a single health-care site, thereby limiting the generalizability of the findings.
About the study
As highlighted above, the existing literature on DMTs does not provide a clear idea about the current treatment landscape regarding population characteristics and treatment types.
Addressing this gap in research, the current study used a large claims database and explored the patterns of use of approved DMTs.
The data to identify adults and children with SCD were obtained from the Clinformatics Data Mart Database between the 1st of January, 2014, and the 30th of September, 2021.
The yearly usage of crizanlizumab, voxelotor, hydroxyurea, and L-glutamine and characteristics of patients were noted. The main aim was to characterize patterns of annual DMT use and understand patient characteristics correlated with DMT use.
Key findings
The sample comprised around five thousand patients with SCD. It was noted that older adults, females, and those who were relatively healthier did not use DMTs.
The health status was inferred by SCD complications, VOC events, and hospitalizations. Individuals with a history of opioid use, more use of health-care services, and more SCD complications were inconsistent DMT users. Avascular necrosis and thrombosis were SCD complications seen among consistent users.
Between 2014 and 2021, an increase in DMT use was observed. In 2014, 19.6% of patients had at least one prescription fill for a DMT.
This percentage increased to 28.3% in 2021, driven largely by the availability of voxelotor and crizanlizumab.
Despite the increase, fewer than 5% of the population was seen to use newer DMTs, and less than 25% used hydroxyurea. A surprising observation was that approximately 75% of patients were not treated with DMT.
Not many studies have explored the use of DMTs at a national level and are hence not indicative of the current treatment landscape. Prior research has also shown the underutilization of hydroxyurea.
These observations align with the findings documented here that the majority of patients did not get at least one prescription fill for hydroxyurea. This was also true when new DMT approvals were considered, i.e., about 72% did not have a prescription fill in 2021.
It was observed that individuals who had some form of DMT use reported more SCD-related complications relative to non-DMT users. This suggests that barriers to using DMT must be explored further.
Future research should uncover how different trajectories of DMT use can influence disease outcomes, and longitudinal studies should be conducted in this regard.
Conclusions
This cross-sectional analysis showed that the uptake of DMTs was persistently low from 2014 to 2021, despite newer therapies being approved. More research should be conducted on the factors that make it easy to use DMTs, and new strategies should be devised to raise DMT uptake.
A key limitation of the present study is that it captures only prescription fill data. Data on actual medication use was unavailable, which could imply that the DMT use has been overestimated in this study.
It must be mentioned that despite the possible overestimation, the implication of the results should remain the same, i.e., sub-optimal use of DMTs.
Additionally, data on patient-level factors affecting eligibility for DMTs could not be accessed. This data could have helped shed light on the reasons for underutilizing DMTs.
The overarching recommendation stands, however, that most individuals with SCD should receive a DMT. Lastly, the Clinformatics data does not have details on patients receiving Medicaid, so the results documented here cannot be generalized to that sub-population.
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