ViaCell Inc. began a pivotal study designed to test the efficacy of ViaCyte in the cryopreservation and thawing of human oocytes, a product aimed at expanding reproductive options for women.

The open-label trial is expected to enroll about 300 women, ages 21 to 35, who are seeking in vitro fertilization and are diagnosed with male factor infertility.

Each patient will undergo traditional in vitro fertilization, with oocyte cryopreservation being performed using ViaCyte after the eggs are retrieved. The oocytes then will be thawed following storage in liquid nitrogen, inseminated and the embryos will be transferred to the patient's uterus in a non-surgical procedure. The trial's primary endpoint is 50 live births.

Last year, the FDA agreed to allow the pivotal ViaCyte trial under an investigational device exemption. Pending successful results, expected in 2009, Cambridge, Mass.-based ViaCell intends to file for regulatory clearance, and ViaCyte could become the first product for oocyte cryopreservation to hit the market.

As large cells with high water content, oocytes historically have proved difficult to freeze, but ViaCell said its technology is based on a choline chloride media that has demonstrated, in earlier studies, the ability to protect cells from damage during the freezing process.

ViaCyte is part of the company's reproductive health division, which already markets ViaCord for the preservation and storage of cord blood stem cells for related use.

That product is designed to preserve a baby's umbilical cord blood at the time of birth for potential treatment of diseases, including blood cancers and genetic disorders.

For the fourth quarter of 2006, ViaCord sales totaled $14.4 million, and the company projects full-year 2007 figures to be between $69 million and $71 million.

On the other side of its business, ViaCell focuses on developing therapeutic products using umbilical cord blood-derived cells and adult stem cells in the areas of cancer, cardiac disease, diabetes and fertility.

The company, which recorded a net loss of $4.6 million for the last three months of 2006 and ended the year with $51.2 million in cash, has said it expects to be cash flow positive in the first half of 2008.

Shares of ViaCell (NASDAQ:VIAC) closed at $5.51 Tuesday, unchanged.