Australians discover treatment for very common female infection

May 22 2011

Starpharma Holdings Limited has announced successful results of a major phase 2 clinical study that demonstrated efficacy of VivaGel^® for the treatment of bacterial vaginosis (BV).

Key Points:

• VivaGel^® meets primary endpoint, demonstrating significant efficacy for treatment of BV
• VivaGel^® expected to avoid many shortcomings of existing therapies
• Trial results support new patent filing which extends VivaGel^® protection to at least 2032
• Planning underway for Phase 3 trials for VivaGel^® for BV treatment
• BV prevention trial of VivaGel^® to commence Q3 2011
• Addressable global market for BV treatment and prevention potentially exceeds $1B

VivaGel^® meets primary endpoint, demonstrating significant efficacy for treatment of BV

The study showed that treatment with VivaGel^® (containing 1% of the active, SPL7013), once daily for seven days, resulted in 74% of patients achieving Clinical Cure of BV 2 to 5 days after completion of therapy compared with just 22% in the placebo group (P=0.0002).

Moreover, 2 to 3 weeks after completion of therapy, 46% of patients achieved Clinical Cure of BV compared with just 12% for the placebo (P=0.006) indicating that VivaGel^® provided lasting cure in a significant proportion of the women.  Both results were highly statistically significant and cure at both time points is considered by clinicians to be important in the clinical management of BV.

The main symptoms of BV are unpleasant vaginal discharge and odour.  In Starpharma’s study, vaginal BV discharge as assessed by the investigator was cured following treatment in 89% of the VivaGel^® treated patients. Unpleasant vaginal odour was cured in 78% of the VivaGel^® treated patients.

Dr Jackie Fairley, Chief Executive Officer of Starpharma, said: "Starpharma’s objective is to develop an efficacious BV product that avoids the side-effects and other shortcomings of conventional antibiotics.”

“This Phase 2 study was a crucial test of the product and these exciting results confirm the significant commercial potential of VivaGel^® for BV. As well as the great outcome for the acute treatment opportunity, we are also very encouraged by the implication of these results for the additional application of VivaGel^® for prevention of BV recurrence.”

“It is particularly pleasing to see such high rates of resolution of symptoms and excellent patient acceptability”, she said.

Existing treatments for BV, such as the conventional antibiotics metronidazole and clindamycin, have published Clinical Cure rates of between 35% and 65% when assessed 2-3 weeks after completion of therapy. Unfortunately, existing products have significant shortcomings in terms of side-effects or tolerability, high levels of antibiotic resistance and in some cases incompatibility with condoms. 

In contrast, whist having comparable efficacy, VivaGel^® is well tolerated, is not absorbed (and so is free from systemic effects), can be used with condoms, and has the real potential to be used for prolonged periods to prevent recurrence of BV.

Clinical Cure 2 to 3 weeks after completion of treatment is currently the US FDA’s preferred endpoint for assessing cure of BV.  In addition to cure of BV achieved with VivaGel^® at that time, acceptability of the product was very high with 83% of patients using 1% VivaGel^® extremely satisfied, very satisfied or satisfied with the product when taking all aspects of the treatment into account, compared with just 35% of patients using the placebo. 

Professor George Kinghorn, of the Department of Genitourinary Medicine at the Royal Hallamshire Hospital, Sheffield, UK, a leading expert in BV and Medical Advisor to Starpharma on this Phase 2 study, commented: “These significant efficacy results are very promising and indicate that VivaGel^® is a potentially useful alternative acute treatment for BV that is different from the systemic and topical antibiotic agents that are the current mainstay of treatment.”

The study was a double-blind, randomized, placebo controlled, dose ranging Phase 2 study and was conducted at sites in the US under an Investigational New Drug (IND) application with the US FDA.  The study enrolled 132 women who were randomized to receive VivaGel^® (0.5%, 1% or 3% SPL7013), or placebo.  The incidence of adverse events, including genitourinary adverse events, was similar across all placebo gel and VivaGel^® groups.  No severe (grade 3) adverse events were observed in the VivaGel^® groups. Two severe adverse events were observed in the placebo.

Additional details and results from the study are provided in the Appendix to this announcement.

Addressable global market for BV treatment and prevention potentially exceeds $1B

The global market for topical BV treatments alone is estimated at approximately US$350M. Starpharma’s modeling suggests the addressable global market for prevention of recurrence of BV is potentially in excess of $1 billion, due to the long term usage associated with such a product. 

Trial results support new patent filing which extends VivaGel^® protection to at least 2032

On the basis of the data from this phase 2 study, Starpharma has filed a new patent application relating to BV that will, once granted, expand and extend patent protection for VivaGel^® to at least 2032.

Planning underway for Phase 3 trials for VivaGel^® for BV treatment

Based on the results of this phase 2 study, Starpharma will undertake further discussions with regulatory authorities, with a view to initiating phase 3 registration trials of VivaGel^® for the treatment of BV in late 2011 or early 2012.

BV prevention trial of VivaGel^® to commence Q3 2011

As previously announced Starpharma is also well advanced in its planning of studies to determine the efficacy of VivaGel^® for this second BV indication and expects to commence this trial in Q3 2011. The very high early cure rate observed in this study is an important observation that is highly relevant to and supportive of the application of VivaGel^® for prevention of BV recurrence.

About Bacterial Vaginosis

BV is the most common vaginal infection worldwide and is particularly prevalent in the US, where it affects an estimated one-third of the adult female population. Similar to imbalances between “good” and “bad” bacteria in the gut, an imbalance in the vaginal microbiota between good bacteria - which help maintain a normal healthy vagina - and harmful bacteria, leads to BV with symptoms including vaginal irritation, discharge and odour that are unpleasant and disrupt and interfere with a woman’s relationships and general quality of life. The condition also has more serious consequences, being implicated in pelvic inflammatory disease and associated with an increased risk of pre-term birth.  BV also significantly increases the risk of some sexually transmitted infections, including HIV. 

Several studies have found an association between BV and acquisition of HIV, with one study indicating that more than 30% of HIV infections in women could be prevented if BV was successfully treated.  Therefore, treatment of BV with VivaGel^® could have a positive indirect impact in reducing HIV acquisition.  

Other Applications of VivaGel^®

VivaGel^® is also being developed as a topical microbicide for the prevention of HIV and genital herpes and as a condom coating. Prevention of human papillomavirus is also under assessment.

www.starpharma.com