Pfizer has announced a link-up with Adolor Corp which will see the two firms develop two novel compounds for the treatment of pain and could lead to a cash boost of over $260 million to the US biotechnology firm.

The compounds, ADL5859 and ADL5747, are delta opioid receptor agonists which Adolor says show potential to treat a wide range of inflammatory, neuropathic and acute pain conditions. The terms of the agreement will see Pfizer and Adolor share revenues and expenses on a 60/40 basis in favour of the New York-based major in the USA. Elsewhere, Pfizer will fund development activities and Adolor will receive royalties.

Cashwise, the Exton, Pennsylvania-headquartered firm will receive an upfront payment of $30 million, plus $1.9 million reimbursement for prior Phase II development costs. Another $232.5 million may end up in Adolor’s coffers depending upon the progress of the compounds and more than 50% of these milestones may be earned prior to regulatory approval. The first payment will be due on commencement of Phase IIb clinical studies.

Adolor will be hoping that will not be in the distant future as ADL5859 is in a Phase II programme which is exploring its analgesic efficacy in inflammatory pain associated with rheumatoid arthritis and acute post-dental surgery pain. Additional studies are planned to evaluate the compound in patients with diabetic peripheral neuropathy and osteoarthritis. Phase I testing of ADL5747 is scheduled to begin in the first quarter of 2008.

Martin Mackay, president of Pfizer Global R&D, said that the deal fits with the firm’s strategy of “expanding our Phase II portfolio with a strong focus in our key therapeutic areas”. He added that his firm “has a strong history in bringing to market novel pain solutions”, including Lyrica (pregabalin), Neurontin (gabapentin) and Celebrex (celecoxib). However, there still remains a significant unmet medical need for patients suffering from a variety of debilitating pain conditions”, Dr Mackay concluded.

Unsurprisingly, investors were impressed with Adolor for signing such a deal and the firm’s shares closed up 19.5% to $4.48. Analysts at Pacific Growth Equities and Broadpoint Capital both upgraded their ratings on the stock to ‘buy’ from ‘neutral’ and the former issued a note saying that “ we believe investors would be well served to own Adolor's stock for the potential for the delta programme”. They added that Pfizer has seen “sufficient merit in the pre-clinical and Phase I data to conclude that the delta programme holds significant promise."

Broadpoint said that the deal “establishes an enterprise value” for Adolor exclusive of Entereg (alvimopan), the investigational bowel drug being developed with GlaxoSmithKline that is having difficulty impressing US regulators, “and transforms the risk/reward profile by implying a floor for the stock."