BioSante Pharmaceuticals will launch the transdermal estradiol gel Elestrin in 2007 as the lowest dose of estradiol currently approved by FDA. The agency cleared the drug for the treatment of moderate-to-severe hot flashes in menopausal women Dec. 15.

Elestrin (formerly called Bio-E-Gel ) was approved in two doses: 0.87 and 1.7 grams per day. The 0.87 grams per day dose is the lowest dose approved for the indication, according to Lincolnshire, Ill.-based BioSante.

"Therefore, potentially, this is the safest product on the market," BioSante told "The Pink Sheet" DAILY, pointing out that FDA, the American College of Obstetricians and Gynecologists and the North American Menopause Society all recommend using the lowest dose of estradiol possible to treat menopause symptoms.

"So we have the FDA and professional organizations recommending the lowest does, and Elestrin is the lowest dose, and therefore, we believe this product should be prescribed by physicians for their patients," BioSante said.

The NDA, submitted to FDA in February, was supported by data from one Phase III trial and three additional clinical trials: a transfer study, a sunscreen study and a pharmacokinetic study (¹ Also see "BioSante Bio-E-Gel Transdermal Estradiol Is Firm’s First NDA" - Pink Sheet, 16 February, 2006.).

The 12-week, 484-patient, Phase III study randomized patients to placebo or one of three doses of Elestrin "to establish the lowest effective dose," BioSante said.

In November, BioSante announced it had signed an agreement with Fairfield, N.J.-based Bradley Pharmaceuticals, which will market Elestrin in the U.S. through its Kenwood Therapeutics Division. The firm will detail the product using approximately 50 sales representatives targeting "estrogen prescribing physicians" in the U.S., most of whom are gynecologists, according to BioSante.

Under the deal, BioSante received roughly $2.6 million upfront. In addition, sales-based milestone payments could bring the total payments from Bradley to BioSante to more than $40 million, according to the firm.

FDA's Elestrin approval triggered an approximately $7.9 million payment from Bradley to BioSante, including $5.3 million to be paid in the next 14 weeks and $2.6 million to be paid within the next year. Bradley will also pay BioSante royalties on sales.

BioSante said that the up-front and milestone payments are "net" of its obligations to Ewing, N.J.-based Antares Pharma, the licensor of Elestrin. Antares could receive more than $13 million in regulatory and sales-based milestone payments from BioSante.

The approval triggered a $2.6 million payment to Antares, including $1.8 million to be paid in the next 14 weeks and the remainder within the next year. Antares, which retains Elestrin rights in Europe and elsewhere, will also receive sales-based milestone payments and royalties.

Elestrin is BioSante's first approved drug. The company's next latest-stage candidate is the testosterone gel LibiGel for the treatment of female sexual dysfunction, for which BioSante hopes to initiate a Phase III trial "within the next month or so."

In addition to BioSante's efforts to establish Elestrin as the lowest-dose drug in the class, other companies are undertaking formulation approaches to differentiate their products. In September, Mountain View, Calif.-based Vivus submitted a new drug application for the metered-dose, transdermal estradiol spray EvaMist , its therapy for hot flashes associated with menopause (² Also see "Vivus Submits NDA For Skin Spray To Treat Hot Flashs" - Pink Sheet, 2 October, 2006.).

Wyeth also submitted an application for a menopause treatment in June, for desvenlafaxine, which could be the first non-hormonal treatment for moderate to severe vasomotor symptoms associated with menopause (³ Also see "Wyeth Files Simultaneous NDAs For Women’s Health Treatments" - Pink Sheet, 26 June, 2006.).

-Daniel Fowler (d.fowler@elsevier.com)

BioSante To Launch Hot Flash Drug Elestrin in 2007

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