Real-World Adherence to Tetrabenazine or Deutetrabenazine Among Patients With Huntington's Disease: A Retrospective Database Analysis

Introduction

Chorea, a common clinical manifestation of Huntington’s disease (HD), involves sudden, involuntary movements that interfere with daily functioning and contribute to the morbidity of HD. Tetrabenazine and deutetrabenazine are FDA-approved to treat chorea associated with HD. Compared to tetrabenazine, deutetrabenazine has a unique pharmacokinetic profile leading to more consistent systemic exposure, less frequent dosing, and a potentially more favorable safety/tolerability profile. Real-world adherence data for these medications are limited. Here, we evaluate real-world adherence patterns with the vesicular monoamine transporter 2 inhibitors, tetrabenazine and deutetrabenazine, among patients diagnosed with HD.

Methods

Insurance claims data from the Symphony Health Solutions Integrated Dataverse (05/2017–05/2019) were retrospectively analyzed for patients diagnosed with HD (ICD-10-CM code G10). Patients were categorized into cohorts based on treatment. Outcomes included adherence, which was measured by proportion of days covered (PDC), adherence rate (PDC > 80%), and discontinuation rates during the 6-month follow-up period (after a 30-day dose stabilization period).

Results

Patient demographic characteristics between the deutetrabenazine (N = 281) and tetrabenazine (N = 101) cohorts were comparable at baseline. Mean ± SD PDC was significantly higher in the deutetrabenazine versus tetrabenazine cohort (78.5% ± 26.7% vs. 69.3% ± 31.4%; P < 0.01). Similarly, a higher adherence rate was observed in the deutetrabenazine versus tetrabenazine cohort, though the difference was not statistically significant (64.1% vs. 55.4%; P = 0.1518). Discontinuation rates were significantly lower in the deutetrabenazine versus tetrabenazine cohort during the 6-month follow-up period (1 month, 3.5% vs. 9.2%; 3 months, 14.7% vs. 23.3%; 6 months, 25.4% vs. 37.2%; P < 0.05).

Conclusions

Results from this real-world analysis indicate that patients treated with deutetrabenazine are more adherent to treatment and have lower discontinuation rates compared with patients in the tetrabenazine cohort. However, a potential limitation is overestimated adherence, as claims for prescription fills may not capture actual use. Additional research is warranted to explore the differences in adherence patterns between treatments, which may inform treatment decision-making.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-021-00309-5.

Long-term adherence to GnRH agonists in men with prostate cancer. A nation-wide population-based study in prostate cancer data base Sweden

Aim: Gonadotropin-releasing hormone (GnRH) agonists are used to treat men with prostate cancer (PCa). To date, no study has fully assessed patterns of adherence to GnRH agonists. We investigated patterns of adherence to GnRH agonists using data from Prostate Cancer data Base Sweden (PCBaSe).Methods: PCBaSe links the National Prostate Cancer Register (NPCR) Sweden to other healthcare registers and demographic databases. Men on primary or secondary GnRH agonists between 2006-2013 entered the study 45 days after GnRH agonists' initiation (run-in period) and exited at 3 years. Medication possession ratio quantified adherents (≥80%). Multivariable logistic regression models included age, injection interval, PCa risk categories, Charlson Comorbidity Index, prior PCa treatment, civil status and year of GnRH initiation. Odds ratios (OR) and 95% confidence intervals (CI) expressed odds of adherence.Results: Men on primary GnRH agonists (n = 8,105) were more adherent with increasing age (75-84 years compared to ≤65 years OR: 1.49; 95% CI: 1.23-1.81), longer injection intervals (365 days compared to 90 days OR: 3.29; 95% CI: 2.52-4.30) and higher PCa risk categories at diagnosis (distant metastasis compared to low risk PCa OR: 3.56; 95% CI: 2.54-5.00). Men on secondary GnRH agonists (n = 4,738) were more adherent with increasing age (≥85 years compared to ≤65 years OR: 1.65; 95% CI: 1.23-2.22) and prior PCa treatment (anti-androgens compared to deferred treatment OR: 1.50; 95% CI: 1.23-1.82), (radiotherapy compared to deferred treatment OR: 1.35; 95% CI: 1.11-1.64).Conclusions: Longer injection intervals could be addressed in the clinical setting to improve adherence.