Stocks for GW Pharmaceuticals, the manufacturers of cannabinoid-based medicines, has fallen sharply after a clinical study failed to show their product Sativex was effective in relieving pain directly associated with cancer.

GW Pharmaceuticals is a British biopharmaceutical company best-known for its cannabis-based product Sativex, which is the original natural cannabis plant derivative to achieve complete market support in any country.

In July 2007, Otsuka Pharmaceutical Co. teamed up with GW Pharmaceutical signing a three year term in which they agreed to a global cannabinoid research collaboration involving research of a variety of GW’s isolated cannabinoids as potential new drug candidates in the field of Central Nervous System (CNS) disorders and oncology.

Researchers at Otsuka Pharmaceutical Co. were so pleased with the results they were witnessing during the first three years of the global cannabinoid research collaboration with GW Pharmaceuticals that they agreed to sign an extension to their research relationship with the company in 2010.

The collaboration’s purpose is to select the most hopeful drug candidates for full clinical development, regulatory approval and global commercialization. The products selected for full development would be the subject of a license from GW Pharmaceuticals.

Under the terms of each product license, Otsuka Pharmaceutical Co. would fund the global development and commercialization of such products, and GW Pharmaceuticals would receive license fees, milestone payments and a long term commercial supply price and royalty. The financial terms of each license are to be agreed at the time of selection of each product for global development.

The initial target suggestion for Sativex in the United States is as a treatment of pain in patients with advanced cancer, who experience insufficient pain relief during optimized chronic opioid therapy. But results from the first of three late-stage trials involving the abovementioned drug as a treatment to alleviate pain in cancer patients found no statistically noteworthy differentiation between subjects using it and those participants that were given a placebo.

GW Pharmaceuticals Chief Executive Justin Gover claimed that the findings were both disappointing and surprising, given heartening results in previous tests, but the company’s scientists are not giving up hope as of yet.

There are still the results from two further Phase III trials which are due later this year and, if encouraging, could still allow the drug to be submitted for treating pain in patients with advanced cancer, where it is designed to be given ahead of opioids.

“Although we missed the primary endpoint in this trial, based upon the positive data seen in the Phase II program, we remain confident in the ability for Sativex to relieve cancer pain in this patient population,” Gover avowed.

News of the results sent shares for GW Pharmaceuticals plummeting by as much as 21 percent, which is surprising considering that the company’s stock was on a roll on hopes for its so-called cannabinoid medicines since the firm listed on NASDAQ in 2013.

Sativex, which is administered as a sublingual spray, is already approved for treating spasticity caused by multiple sclerosis in 27 countries, although not yet in the United States.