Penwest Pharmaceuticals has conceived and developed an oral extended release formulation of nalbuphine hydrochloride (“nalbuphine ER”), an agonist/antagonist opioid for the treatment of moderate chronic nociceptive pain. Independent market research confirms that nalbuphine ER may be a preferred option for the treatment of chronic lower back pain or pain associated with osteoarthritis of moderate intensity. To date, eight clinical trials with nalbuphine ER have been completed, including Phase II trials in both acute and chronic pain. The company will continue to invest in a major clinical program for nalbuphine ER in North America. In parallel, Penwest is seeking a European partner with the experience, infrastructure and resources necessary to realize the full value of this innovative product.

A number of drugs, many of which are available as generics, are used for the treatment of chronic pain. Typically, tramadol immediate release, a weak agonist (i.e., fixed doses of codeine or hydrocodone combined with acetaminophen or aspirin), or NSAIDs are used as initial therapy for chronic moderate lower back pain. However, treatment failure is extraordinarily common. Nearly 70% of patients who initiate treatment with tramadol or NSAIDs fail to achieve pain relief due to a lack of efficacy and/or side effects.  And while fewer patients fail following initiation with a weak agonist, these therapies are associated with a relatively higher propensity for abuse/addiction.

Generally, physicians will switch to another class when treatment failure has occurred. For example, nearly 60% of physicians will switch from tramadol to an agent from a different class when the patient fails first-line tramadol therapy. For weak agonists, the switch rate is nearly 75%. For those patients who are started on an NSAID and fail to achieve pain relief, physicians add another agent in over 50% of cases.

Based on our market research and on our clinical results to date, Penwest believes that nalbuphine ER can compete favorably in several market segments:

•     Patients who would be prescribed a weak agonist or a tramadol product.

•     As add-on therapy to NSAIDs.

•     For those patients who cannot or will not initiate strong opioid therapy.

Penwest Pharmaceuticals is actively seeking a co-development and commercial partner. The partner will have the opportunity to participate in the clinical development of nalbuphine ER. The partner will also have the opportunity to share in all Preclinical and Clinical data already generated by Penwest Pharmaceuticals.

Formulation, blood level, ethanol resistance, and abuse deterrence patents have been filed or awarded for our nalbuphine formulation.

Licensing of the formulation in exchange for upfront payments, milestones, and royalties.