INTRODUCTION: Surgical site infiltration with bupivacaine results in short-lived analgesia. The MATRIX-1 and MATRIX-2 studies examined the efficacy and safety of the bioresorbable bupivacaine HCl collagen-matrix implant (INL-001) for postsurgical pain after open inguinal hernia repair. INL-001, designed to provide early and extended delivery of bupivacaine, provides prolonged duration of perioperative analgesia. METHODS: In two phase 3 double-blind studies [MATRIX-1 (ClinicalTrials.gov identifier, NCT02523599) and MATRIX-2 (ClinicalTrials.gov identifier, NCT02525133)], patients undergoing open tension-free mesh inguinal hernia repair were randomized to receive 300-mg bupivacaine (three INL-001 100-mg bupivacaine HCl collagen-matrix implants) (MATRIX-1 n = 204; MATRIX-2 n = 213) or three placebo collagen-matrix implants (MATRIX-1 n = 101; MATRIX-2 n = 106) during surgery. Postsurgical medication included scheduled acetaminophen and as-needed opioids. RESULTS: Patients who received INL-001 in both studies reported statistically significantly lower pain intensity (P ≤ 0.004; primary end point) and opioid analgesic use (P < 0.0001) through 24-h post-surgery versus those who received a placebo collagen-matrix. Patients who received INL-001 reported lower pain intensity through 72 h (P = 0.0441) for the two pooled studies. In both studies, more of the patients (28-42%) who received INL-001 used no opioid medication 0-24, 0-48, and 0-72 h post-surgery versus those who received a placebo collagen-matrix (12-22%). Among patients who needed opioid medication, patients receiving INL-001 used fewer opioids than those who received a placebo collagen-matrix through 24 h in both studies (P < 0.0001) and through 48 h in MATRIX-2 (P = 0.0003). Most adverse events were mild or moderate, without evidence of bupivacaine toxicity or deleterious effects on wound healing. CONCLUSION: These findings indicate that INL-001 results in post-inguinal hernia repair analgesia that is temporally aligned with the period of maximal postsurgical pain and may reduce the need for opioids while offering a favorable safety profile. TRIAL REGISTRATION: ClinicalTrials.gov identifiers, NCT02523599; NCT02525133. FUNDING: Innocoll Pharmaceuticals. Plain language summary available for this article.