Consider this scenario: Let’s say you sold a leading mouthwash but feared that marketing a test for detecting oral cancer would raise concerns about a study showing a link between the mouthwash and oral cancer. Would you proceed or break the contract? Well, Oral Cancer Prevention, which makes such a test, claims Johnson & Johnson, which sells Listerine, reneged on a deal.

And so Oral Cancer Prevention has filed a lawsuit charging J&J with suppressing sales of a test that allegedly could have prevented an estimated 7,300 cases of oral cancer and an unknown number of deaths in order to protect Listerine, which generates some $1 billion in annual sales. The company notes oral cancer is difficult to detect until its later stages, but its OralCDx test would help dentists detect the 4 percent of patients with precancerous cells.

The background: J&J allegedly courted OCP and a sales agreement was signed in late 2009 with OraPharma, which at the time was a J&J subsidiary and had the reach with dentists nationwide to quickly boost sales of the OCP test. But within days, J&J remembered a paper was published the previous year in the Australian Dental Journal, which concluded “alcohol-containing mouthwashes contribute to the increased risk of development of oral cancer and further feel that it is inadvisable for oral healthcare professionals to recommend the long-term use of alcohol-containing mouthwashes” (read the abstract here).

By the end of 2009, Listerine sales in Australia dropped by roughly half, according to the lawsuit. And so J&J Consumer Products vp Jim Murphy allegedly told OCP president Mark Rutenberg that J&J “was leery of highlighting the risk of oral cancer and was worried that if OraPharma were to sell both Listerine and OralCDx, it would lend credence to the link between Listerine and oral cancer, and could be construed as a tacit acknowledgment by J&J of the validity of the conclusions of the Australian oral cancer study,” the lawsuit states.

And what OCP claims what was not disclosed at the time was that, in response to the study, J&J had “secretly” planned to launch a new alcohol-free mouthwash called Listerine Zero and was worried that promoting Listerine Zero and the OralCDx test simultaneously would expose the real reasons for launching Listerine Zero.

“Listerine Zero was carefully branded to conceal the fact that it was developed primarily in response to the Australian mouthwash oral cancer study and the subsequent sales drop in Listerine’s Australian sales. The advertising for that product makes no mention of the fact that it may reduce the risks associated with mouthwashes containing alcohol and instead emphasizes only its ‘less intense’ flavor,” according to the lawsuit.

Meanwhile, in early 2010, the J&J subsidiary promised a huge roll-out and, as part of the exclusive sales agreement, required OCP to eliminate its sales force and terminate other distribution deals. But then J&J restricted its own sales team from widely marketing the test and instead focused on dentists “whose practices were oriented toward providing the most basic dental services, with little or no attention to broader soft tissue care,” the lawsuit states.

As a result, the alleged J&J “scheme” to take control of OralCDx and prevent the test from becoming part of routine screening throughout the US succeeded. By June 2010, JYJ’s OraPharma 100-plus member sales team, which had access to more than 50,000 dentists, had made fewer than 50 percent of the sales that OCP’s four-person sales team had made in the six months before their deal.

A few weeks later, J&J sold OraPharma and terminated the agreement with OCP (you can read the lawsuit here). We have asked J&J for a comment and will update you accordingly. UPDATE: A J&J spokeswoman sends us this: “Johnson & Johnson is aware of the complaint that has been filed by OCPI. The company is confident that we have engaged in proper business practices and we look forward to the opportunity to resolve this matter through the legal system.”