Irish firm Horizon Pharma has increased its offer to acquire US-based Depomed, which produces products to treat pain and other central nervous (CNS) system conditions.

The company has increased its all-stock acquisition proposal to $33.00 per share from $29.25 per share, representing a 60% premium to the closing price of Depomed on 6 July.

Earlier this month, Horizon proposed to acquire all outstanding shares of Depomed for a per share consideration of $29.25, which valued at around $3bn.

Depomed confirmed that it has received a purported revised, highly conditional, unsolicited and non-binding proposal from Horizon to purchase all of the outstanding shares of the company.

"We are resolute in our commitment to acquire Depome."

Horizon Pharma president and CEO Timothy Walbert said: "Based on discussions we’ve had with Depomed’s largest shareholders as well as our own shareholders, it is clear that they and the investment community strongly support a combination of our two businesses.

"We are resolute in our commitment to acquire Depomed and we call upon Depomed’s board of directors to listen to their shareholders, fulfil their fiduciary responsibilities and meet with us in order to promptly complete a negotiated transaction."

Depomed’s Nucynta franchise comprises Nucynta ER (tapentadol) extended release tablets indicated to manage pain, including neuropathic pain associated with diabetic peripheral neuropathy (DPN) and Nucynta (tapentadol) that is an immediate release version of tapentadol to manage moderate to severe acute pain in adults.

The firm also produces Zipsor (diclofenac potassium) Liquid Filled Capsules that are non-steroidal anti-inflammatory drug indicated for relief of mild to moderate acute pain in adults and Lazanda (fentanyl) Nasal Spray, which is an intranasal fentanyl drug used to manage breakthrough pain in adults.

In addition, it produces Gralise (gabapentin) which is a once-daily treatment approved to manage postherpetic neuralgia.

Cambia (diclofenac potassium for oral solution) is a non-steroidal anti-inflammatory drug indicated for acute treatment of migraine attacks with or without aura in adults.