More than 50 additional employees and ex-workers at Eli Lilly have joined a lawsuit against the drugmaker, accusing it of racial discrimination

The Indianapolis Star newspaper reports the plaintiffs' attorney as saying that the workers include current and former sales representatives, production workers and office workers from various Lilly locations. The employees, who are black, say they have been subjected to pay discrimination, a hostile work environment and unfair termination.

"There's a pattern that's going on at the company and it's a pattern that's got to stop," said Josh Rose, of the Washington law firm of Rose & Rose, to a crowd of about 70 people who gathered on the steps of the US District Courthouse in Indianapolis. The newspaper says that the rally was organised by plaintiffs and the National Association for the Advancement of Coloured People, the USA's largest civil rights organisation.

The case began last year when four employees and ex-staff filed a racial discrimination suit in federal court last year, alleging that Lilly paid blacks less and promoted them more slowly than their white peers. The suit, still in early stages, seeks class status.

Lilly has denied it treats or pays black workers differently than whites, but would look into the new claims by black workers. The The Indianapolis Star quotes Patty Martin, Lilly’s vice president for global diversity, as saying that the company will “promptly and thoroughly investigate these new allegations”.

However, Ms Martin added that the original lawsuit filed by four plaintiffs was groundless, and that the company is "disappointed" in the decision by the NAACP to join the complaint.