Long-Term Safety of EXPAREL™ (Bupivacaine Extended Release Liposome Injection) Reveals no Impact on Silicon Breast Implants at up to Two Years Follow-Up

Purpose:  EXPAREL is an investigational long-acting local analgesic.  Efficacy and safety have been studied in multiple surgical models.  An issue specific to the augmentation mammoplasty model is the long-term safety of EXPAREL in the presence of silicon breast implant material; this is investigated herein.

Materials and Methods:  Prior phase 2 and phase 3 multi-center, randomized, active-control studies with EXPAREL in the presence of a sub-muscular augmentation mammoplasty had been performed.  All sites were invited to bring all patients in for a long-term follow-up study, which included a focused history and physical examination to elicit any clinical sequelae due to potential impact of EXPAREL on the silicon prosthesis.

Experience:  The total number of potential participants was 175 patients across a total of 15 centers in the United States; there were a total of 147 patients across the 11 centers that were able to participate and 94 participated:  63 from phase 3 (47% of those eligible) and 31 from phase 2 (78% of those eligible).  Follow-up ranged from 13 months to 24 months (mean of 17 months).  Depending on the initial protocol, patients had received either 300mg EXPAREL in each breast, 100mg bupivacaine in each breast, 300mg EXPAREL in one breast/75mg bupivacaine in the other, or 150mg EXPAREL in one breast/75mg bupivacaine in the other.  Patient’s mean age was 32 years old (range:  20-54), 87% were white, and volume of implant averaged 380cc. 

Results:  Most patients reported no changes in size/shape of the breast or changes in the skin/nipple.  One patient reported signs of irritation or implant leakage; the relevant breast had received 75mg bupivacaine.  One patient had one implant removed due to breast cancer 15 months after receiving study drug; the relevant breast had received 100mg bupivacaine.   

Conclusions:  In this study, at up to two years of follow-up, EXPAREL in the presence of silicon breast implant material did not have any impact on normal healing and there were no drug related late stage clinical sequelae, nor any effect on the implant material.