2025 - Acute Pain Models in Drug Development

Human pain models have been established as effective, cost-efficient tools for evaluating the efficacy of analgesic drugs. Over the past few decades, three acute pain models have been most commonly used: bunionectomy, third molar extraction and abdominoplasty. Each of these procedures offers unique benefits but also comes with some limitations. The third molar extraction model is an inpatient procedure with post-op monitoring for 24-48 h, high assay sensitivity and rapid enrollment. This model is commonly used for medications with low analgesic efficacy or as a proof-of-concept model for analgesic medications in development. The abdominoplasty model does not require a disease or a specific diagnosis but has exhibited variability among study participants due to its episodic nature of post-surgical pain and often requires a multi-center approach to meet recruitment objectives. While the third acute pain model, bunionectomy, will be the primary focus of this webinar, the speakers will also discuss the critical factors that distinguish all three acute pain models, such as benefits, limitations, study timelines and cost differences between each model.
The bunionectomy model has been used for more than 25 years to evaluate oral, topical, parenteral and implantable analgesic medications. The wide variety of completed bunionectomy studies highlight its proven reliability with high assay sensitivity for evaluating analgesia. The post-surgery acute pain model consists of a short, standardized inpatient procedure (30-90 min) using different types of anesthesia with post-surgery monitoring ranging from 48 h to 7 days depending on the needs of the study. The procedure involves manipulating many different tissue types, which results in moderate to severe acute pain that typically plateaus for 48-72 h.
Despite the numerous benefits of this acute pain model, it does come with a few challenges. Adequate and consistent training to reduce variability is a key challenge that encompasses training caregivers, raters and family members. Despite the bunion deformity being a prevalent condition across all populations, recruitment that maintains diversity within the study population can be a difficult challenge to overcome. While relevant to all three acute pain models, patient-specific pain tolerance, which influences self-reported pain scales, and maintaining a consistent and controlled environment are important challenges for minimizing variability and confounding factors in acute pain models.
Despite these challenges, the bunionectomy model continues to be a valuable tool with validated clinician-rated and patient-rated assessments for evaluating both efficacy and safety of pain management interventions. Clinician-rated evaluations are frequently used to assess safety, such as the Modified Observer’s Assessment of Alertness and Sedation (MOAA/S) and the Columbia-Suicide Severity Rating Scale (CSSRS). Participant-rated assessments are commonly used to evaluate a medication’s analgesic efficacy and include time to onset of perceived and/or meaningful relief as well as pain at rest and pain with movement rated on the Numerical Rating Scale (NRS) or the Visual Analog Scale (VAS). Given its proven track record of success and favorable experimental conditions, bunionectomy has been the most used acute pain model and is the gold standard for evaluating an analgesic’s efficacy in a controlled environment.
Register for this webinar today to explore the value of acute pain models for evaluating analgesic drug development.
Keywords: Drug Development, Drug Discovery, Analgesic, Pain Management, CRO, Drug Manufacturing, Chronic Pain, Pain, Patient Enrollment, Pain Relief, Study Enrollment, Clinical Trial Enrollment