“Many women across the country believe that they suffered pay discrimination while working at Merck,” said David Sanford, chairman of Sanford Heisler and co-lead counsel for the plaintiffs, in a statement. “What started out as one woman against a corporation has now grown to more than four hundred.”

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The complaint, Smith et al. v. Merck & Co., Inc. et. al., claims that Merck regularly paid female sales representatives less than their male counterparts, denied women opportunities for career advancement, pressured pregnant women or mothers to quit their jobs, and created a hostile work environment that fostered sexual harassment. The suit is being pursued under the Equal Pay Act and Title VII of the Civil Rights Act (although request for a class action under the latter has yet to be approved).

A federal judge in New Jersey had given preliminary approval for the equal pay class action in April, saying that the former sales representatives who had launched the complaint had produced sufficient facts to support expanding the suit. Merck has consistently said that the case “lacks merit” and has promised to “vigorously defend itself.”

Sanford Heisler and allied firm Feinstein Doyle Payne & Kravec began to recruit current and former female sales representatives for the suit in June, sending authorized notice about the class action to 3,183 women.

There are now 405 women involved in the suit and there are three more weeks for the plaintiffs to recruit more. Sanford Heisler says it will continue to pursue class action status for the plaintiffs’ non-pay related systemic gender discrimination complaints.