Reviewed by: David Cluck, PharmD; East Tennessee State University
Bottom Line: β-lactam allergy re-labeling is possible either via patient reporting or lack of a mechanism to adequately capture oral challenge or penicillin skin test results. Patient education also remains a critical component of de-labeling sustainability. The findings of this secondary analysis indicate single dose oral challenge from the PALACE trial is associated with durable safety in patients who were previously de-labeled.
The PALACE trial investigated whether a direct oral penicillin challenge (DOC) is noninferior to the standard of care of penicillin skin testing followed by an oral challenge in patients with a low-risk penicillin allergy.1 In this secondary analysis, Copaescu and colleagues evaluated long-term follow-up and risk factors associated with the persistence or reinstatement of self-reported penicillin allergy (SRPA) following a successful oral challenge with penicillin and subsequent allergy label removal.2 Using DOC as the intervention arm from the PALACE trial, a 6-month post-randomization questionnaire to assess SRPA, adverse events and factors associated with SRPA. Among 377 patients who were de-labeled in the initial trial, 351 completed the 6-month follow-up. Of these patients, 23 (6.6%) described SRPA (intervention group: 13 of 178 [7.3%]; control group: 10 of 173 [5.8%]). Of the 23 with SRPA, 11 (47.8%) reported an adverse event (AE) during the 5-day study period, 7 (30.4%) were associated with a new AE, and 5 (21.7%) identified as having a SRPA without an AE. Among the AEs reported after the 5-day initial follow-up and associated with new penicillin-based antibiotic treatment, 11 of 13 were immune-mediated (0.3%). According to a large retrospective study, a mild delayed reaction is not an uncommon finding after de-labeling patients.3 Moreover, among patients reporting a SRPA, 17 (73.9%) took an antibiotic within 6 months of de-labeling ([11 of 17] received a β-lactam). In the non-SRPA group, 123 of 328 (37.5%) were prescribed an antibiotic course; 66 of 123 were penicillin-based regimen. A small cohort of patients in each arm still considered themselves to be allergic to penicillin, emphasizing both the importance and limitations of patient education as part of effective de-labeling.
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