BioWorld International Correspondent
LONDON - Shares in Xenova Group plc received a much-needed boost last week when the company announced progress with two clinical programs, in cocaine addiction and human papillomavirus vaccines to treat cervical dysplasia and cervical cancer.
News that patient dosing has begun in a Phase IIa trial of TA-CD for the treatment of cocaine addiction, and of clinical responses in a prime-boost study of the two vaccines, pushed Xenova's share price up by 9 percent to 12.25 pence.
The open-label trial of TA-CD will involve cocaine addicts who, while volunteering for the trial, are not actively seeking to quit. CEO David Oxlade said, "TA-CD has made promising progress in earlier clinical studies, and this additional trial is designed to show for the first time whether addicts' behavior can be altered by administration of the TA-CD vaccine."
TA-CD, a cocaine derivative conjugated to a carrier protein, has been shown to generate antibodies that bind cocaine in the bloodstream. That prevents it from crossing the blood-brain barrier and causing a high. It is intended that the vaccine be used alongside behavioral therapy programs to prevent addicts who relapse from reaching a high, and thus increasing their chances of giving up the drug.
The effects of TA-CD will be assessed by comparing subjects before and after a four-dose immunization course. The trial is partially funded by the U.S. National Institute on Drug Abuse.
An earlier Phase IIa study found an attenuation of the usual euphoric effects of cocaine in five of six subjects who relapsed, indicating possible benefit from TA-CD.
In the second report of clinical progress, an open-label trial of Xenova's TA-CIN and TA-HPV therapeutic vaccines in a prime-boost study showed the combination was safe and well tolerated.
TA-HPV is being developed for use along with surgery in cervical cancer, and TA-CIN for the treatment of cervical dysplasia. Of 26 women in the study, there were a range of positive responses, including symptomatic improvements and a reduction in viral load. One woman had a complete response, with the lesion gone and complete clearance of HPV. Assessments are continuing to see whether patients with a partial response go on to a complete response. Xenova said the results indicate further development is warranted.
Xenova, based in Slough, succeeded in raising £11 million (US$17.3 million) in a rights issue in September. However, the company lost almost half its market value in February when partner QLT Inc., of Vancouver, British Columbia, announced patient recruitment in two Phase III studies of tariquidar was suspended because of safety concerns. The trials of the drug, designed to prevent tumors developing resistance to chemotherapeutics, are held up pending an interim safety and efficacy analysis.