Exparel is a non-opioid analgesic, developed to provide postsurgical pain relief. It is a long acting liposome injection of bupivacaine, a drug widely used to treat postsurgical pain. Exparel is being developed by Pacira Pharmaceuticals.

The US Food and Drug Administration (FDA) approved Exparel in October 2011. Exparel is expected to meet a huge clinical unmet need for non-opioid analgesics.

Postsurgical pain

“It is a long acting liposome injection of bupivacaine, a drug used to treat postsurgical pain. Exparel is developed by Pacira Pharmaceuticals.”

Postsurgical pain is a natural reaction to the tissue trauma caused during surgery. Tissues and nerve endings in the body are traumatised during surgery, causing pain.

Management of postsurgical pain is essential to help in early recovery of patients after surgery. If postsurgical pain is not managed, it increases hospital readmission rates and healthcare costs.

Existing treatments available for management of postsurgical pain include a combination of several therapies because no single drug is able to treat all types of pain. One of the treatment options is administration of anaesthetics, such as bupivacaine at the incision site. Bupivacaine, however, has a relatively shorter duration of efficacy of seven hours, requiring the use of additional pain medications to provide relief.

Elastomeric pain relief pumps, which are balloon-type devices, are used to inject non-narcotic anaesthetic at the incision site through a small catheter. This treatment requires the patient to wear the device for three to five days, which can limit their ability to resume normal activities.

The most common treatment used for pain relief is the use of opioids. This treatment, however, is associated with several unwanted side effects including sedation, dizziness and nausea.

Other treatments include non-steroidal anti-inflammatory drugs which have similar side effects as that of opioids. Nerve blocking agents are also used to block the nerve near the incision site. This treatment is ineffective if the pain is not localised.

Exparel – bupivacaine liposome injectable suspension

Exparel is a combination of bupivacaine with DepoFoam which can provide pain relief for up to 72 hours.

DepoFoam is a product delivery mechanism which encapsulates the drug in multivesicular liposomal particles releasing it over a period of time without changing composition. Using this technology, bupivacaine can be delivered for an extended period of time, reducing the need to use other pain medications and opioids.

Clinical trials

Exparel has been tested in 21 clinical trials involving more than 1,300 patients undergoing different types of surgeries including total knee replacement, colonic surgery abdominal hysterectomy and shoulder surgery.

“Exparel is a non-opioid analgesic, developed to provide postsurgical pain relief.”

The safety profile of Exparel was tested in ten clinical trials including 823 patients.

Approval of Exparel was based on two pivotal Phase III trials. One trial was conducted on 193 patients undergoing bunionectomy. The multicenter, randomised, double-blind clinical trial met its primary end point in October 2009.

Compared to placebo, Exparel was able to reduce pain in the first 24 hours only.

The second trial was conducted on 189 patients undergoing hemorrhoidectomy. The trial met primary end point in December 2009. Exparel was able to provide pain relief for up to 72 hours compared to placebo.

Marketing commentary

An estimated 70 million surgeries are carried out yearly in the US. Of these procedures, about five million use bupivacaine for pain relief. About 75% of the patients receive inadequate postsurgical pain relief according to a study.

Considering the huge clinical unmet need for pain relief in the US, the potential annual sales of Exparel are estimated at 39 million.

Pacira is planning to utilise opportunities in the global market for the management of postsurgical pain. Depending upon the size of these opportunities, Pacira plans to pursue commercial partnerships outside the US.

Pacira also plans to develop formulations for the management of pain in animal health. It will explore potential partnerships in this area to develop and commercialise these formulations.

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