Patients with rheumatoid arthritis being treated with a Janus kinase (JAK) inhibitor or a tumor necrosis factor inhibitor showed no significant difference in their medication continuation rates or proportion of days covered (PDC) following the US Food and Drug Administration’s (FDA) decision to place a black box warning on JAK inihibitors, Samantha Delgado, PharmD, from the University of Florida reported during her presentation at ACR Convergence on November 13.

She noted that the FDA had applied the black box warning to JAK inhibitors following results from the ORAL Surveillance study, which indicated that the drug increased the risk of major adverse coronary events. Tumor necrosis factor-α inhibitors (TNFi) do not carry a black box warning for these adverse events. It is unknown if prescribing patterns or patient behavior was impacted in response to the new black box warning.

Dr Delgado and colleagues undertook this retrospective cohort study of RA patients receiving a JAK inhibitor or TNFi to assess if prescribing patterns or patient behaviors were impacted by the black box warning.

Patients who received at least 3 fills for a JAK inhibitor or TNFi between April 1, 2021, and August 31, 2022, and maintained coverage through the latter date. “Three periods were assessed,” she explained, “pre-black box warning (4/1/2021 – 8/31/2021), washout (9/1/2021-12/1/2021), and post-black box warning period (12/2/2021-8/31/2022). Propensity score matching was conducted utilizing the patient's demographic profile, including age, gender, socioeconomic status (SES), location, and comorbid conditions.”

The investigators measured patient adherence using proportion of days covered (PDC), which was evaluated overall and during each period. If the last medication fill occurred more than 30 days from the end of the study the drug was considered discontinued.

A total of 815 patients were included in the unmatched analysis, of whom 215 (26.4%) received JAK inhibitors. While some differences in age and gender were found between JAK inhibitor and TNFi patients, there were no differences seen in SES or comorbidity.

“Patients prescribed JAK inhibitors had higher median PDC (5.6%; p=0.022) during the study compared to TNFi patients and higher median PDC (7.1%; p = 0.014) during the post-black box warning period,” Dr Delgado stated. “No difference in discontinuation rates were found overall and stratified by study period. After matching, 408 patients were evaluated with 50% receiving JAK inhibitors; no differences in underlying demographics or comorbidities were found.”

Adherence metrics were similar between matched cohorts, as well, she stated, with no significant differences in median PDC (1.8%; p=0.235) or discontinuation rates (28.9% vs 27.9%), in JAK inhibitor and TNFi groups, respectively.

“Adherence and persistence to JAK inhibitors were not significantly impacted by the addition of the black box warning,” she concluded.

Delgado S. 2142: Adherence patterns in rheumatoid arthritis patients receiving a Janus kinase (JAK) inhibitor or a tumor necrosis factor α inhibitor (TNFi) after the addition of a black box warning to JAK inhibitors. Presented at: American College of Rheumatology Convergence. November 12, 2023. San Diego.