Sativex® Commences US Phase II/III Clinical Trial in Cancer Pain

 

Sativex® Commences US Phase II/III Clinical Trial in Cancer Pain

26  November  2007

GW Pharmaceuticals plc (AIM: GWP) and Otsuka Pharmaceutical Co., Ltd. today announced that the first US Phase II/III dose-ranging trial has been initiated to evaluate the efficacy and safety of Sativex® in the treatment of pain in patients with advanced cancer, who experience inadequate analgesia during optimized chronic opioid therapy.

The principal investigator of this study is Dr. Russell K. Portenoy, Chairman of the Department of Pain Medicine and Palliative Care at Beth Israel Medical Center in New York City. This five-week, placebo-controlled study will include approximately 40 centers primarily in the US and recruit a total of 336 patients. Patients enrolled in this study must have advanced cancer for which there is no known curative therapy and have a clinical diagnosis of cancer-related pain, which is not wholly alleviated with their current opioid treatment. The primary objective of the study is to evaluate the potential role and dose range of Sativex in these patients as an adjunct to their pre-existing pain medications. The primary endpoint of the study will be the response rate for patients at the end of 5 weeks of therapy, as defined by a 30% or greater reduction in the 11-point, Numeric Rating Scale (NRS).

Commenting on the importance of this study, Dr. Portenoy, said, “Studies suggest that more than one-third of patients with cancer, and more than three-quarters of those with advanced disease, have chronic pain. Large surveys indicate that optimal opioid therapy does not yield sufficient relief in a substantial proportion of these patients. There is a clear need for new treatments to improve these outcomes and it is our hope that cannabinoid formulations may represent an important option in the future. This US-based study is a welcome step in assessing the role of Sativex®as a potential new treatment for cancer pain."

Dr Geoffrey Guy, GW’s Chairman, said, “GW has spent many years preparing for the US development of Sativex®and has established open and positive interactions with relevant federal agencies. The start of the first large scale US clinical trial is a major milestone for the company and for the future prospects for Sativex®. We are delighted to be working in close collaboration with our partner, Otsuka, in advancing Sativex®toward the goal of obtaining US regulatory approval."

Dr. Taro Iwamoto, President of Otsuka Pharmaceutical Development and Commercialization, Inc., likewise noted that “Otsuka is very excited to be working with GW Pharmaceuticals for the development of this potential alternative approach to the treatment of advanced cancer pain. The initiation of this US clinical trial for Sativex is consistent with our mission to develop products for better health.”

Sativex®is an investigational new product composed primarily of two cannabinoids: CBD (cannabidiol,) and THC (delta 9 tetrahydrocannabinol). Sativex®will be administered as a metered dose oro-mucosal spray each 100µL spray contains 2.7mg THC and 2.5mg CBD. The Sativex®formulation is standardized by both composition and dose and is supplied in small spray vials. The components of Sativex have been shown to bind to cannabinoid receptors that are distributed throughout the central nervous system and in immune cells.

This Phase II/III dose ranging study will attempt to replicate and extend data from a previous, two-week clinical trial in 177 patients conducted in Europe. In this European study, Sativex®was administered to patients with terminal cancer and persistent pain that was not fully relieved by current strong opioid therapy. The primary endpoint of this study was the change from baseline to endpoint in the NRS pain score. Sativex, as adjunctive treatment to strong opioid therapy, was associated with a larger decrease in NRS score than was placebo and strong opiods (p=0.014). In addition, 43% of patients who received Sativex®, while remaining on opioids, exhibited at least a 30% decrease in their pain score compared to 21% of patients receiving placebo and opioids (p= 0.024)

Treatment related adverse events in this study were reported by 85% of patients receiving Sativex and by 75% of patients receiving placebo. The most common adverse events (> 10%) reported by patients in this study were somnolence (15% Sativex®vs. 13% placebo); nausea (12% Sativex®vs. 11% placebo) and dizziness (12% Sativex®vs. 5% placebo). Serious adverse events reported by more than one patient receiving Sativex were urinary retention (n=2) and progression of the underlying cancer (n=6).