Dare Bioscience announces publication of clinical findings for DARE-VVA1
Dare Bioscience (DARE) announced the publication of clinical findings for vaginally-administered tamoxifen in Clinical and Experimental Obstetrics and Gynecology, an international journal for publication of research focused on the development of new therapeutic interventions for obstetrics and gynecology.
Dare’s product candidate, DARE-VVA1, incorporates tamoxifen in a proprietary formulation designed for vaginal delivery.
Dare holds the exclusive worldwide rights to patents issued in the U.S. and Japan covering the use and delivery of DARE-VVA1 for vulvar and vaginal atrophy, or VVA, and a U.S. patent covering composition, use and delivery of DARE-VVA1 for VVA.
The publication reported that a self-administered vaginal suppository containing tamoxifen, dosed daily for one week followed by twice weekly for three months, administered to four healthy postmenopausal women with VVA showed significant improvements in reducing vaginal pH and vaginal dryness without significant systemic absorption of tamoxifen.
This exploratory study demonstrated that tamoxifen was effective when delivered intravaginally for three months in postmenopausal women suffering with VVA.
The median vaginal pH at the time of enrollment was 7.1. At the end of month 3, the median vaginal pH was 5.0. The median paired difference between baseline and month 3 was -2.0, with a range of -2.5 to -1.5.
The self-assessment of vaginal dryness improved between baseline and month 3. Vaginal dryness was rated using a visual analogue scale, or VAS, that ranged from 0 to 10.
Tamoxifen commonly is used as a breast cancer treatment
At baseline, the median vaginal dryness rating was 8.0, with a range of 7.5 to 9.0. At the end of month 3, the median vaginal dryness rating was 3.0, with a range of 2.0 to 3.0. The median change between baseline and month 3 was -5.5.
In addition, systemic exposure was at least an order of magnitude lower following vaginal administration compared with oral tamoxifen. After eight weeks of study treatment, median plasma concentration of tamoxifen was 5.8 ng/ml, with a range of 1.0 to 10.0 ng/ml.
In comparison, after three months of oral administration of 20-mg tamoxifen once daily, the average steady state plasma concentration of tamoxifen is 122 ng/ml, with a range of 71 to 183 ng/ml. VVA is an inflammation of the vaginal epithelium due to the reduction in levels of circulating estrogen. Historically, estrogen-based therapies delivered through creams, rings and tablet supplements have been prescribed for the treatment of VVA symptoms.
However, estrogen-based products can be worrisome for women undergoing treatment for hormone-receptor positive breast cancer and are often contraindicated in such breast cancer patients and in patients with a genetic predisposition or history of familial disease, because of the concern that estrogen use will promote recurrence of disease.
Many breast cancer survivors undergo menopausal symptoms as a direct consequence of cancer treatment.
Breast cancer patients treated with aromatase inhibitors refer to VVA as one of the most unpleasant side effects of treatment. Tamoxifen has been a commonly used treatment for breast cancer and is systemically metabolized to active metabolite 4-hydroxy-N-desmethyl-tamoxifen, otherwise known as endoxifen. In breast tissue, tamoxifen acts as an estrogen antagonist.
In other tissue, including vaginal tissue, tamoxifen has been reported to exert an estrogen-like response on vaginal cytology by a mechanism yet to be understood and not expected based upon its an anti-estrogen activity.
This exploratory study demonstrated that vaginal administration of tamoxifen for three months in postmenopausal women with VVA is a possible new, non-estrogen-based treatment approach.
Dare is currently conducting activities in preparation for future clinical work with DARE-VVA1, its proprietary vaginal formulation of tamoxifen.
If successful, DARE-VVA1 could be the first and only vaginally administered tamoxifen product approved by the FDA for the treatment of VVA in hormone-receptor positive breast cancer patients.
DARE closed at $0.90, last traded at $2.70.
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