A US judge in Virginia has ruled that three researchers did not defame Johnson & Johnson by publishing research linking cosmetic talcum powder products to mesothelioma, a rare form of cancer, Reuters reported.Johnson & Johnson sued doctors Theresa Emory, John Maddox and Richard Kradin, alleging they defamed the company in a 2020 scientific article, Reuters reported.What the study foundThe article examined 75 patients with mesothelioma who had no known connection to asbestos exposure other than through cosmetic talc products such as baby powder.US District Judge Jamar Walker ruled in favour of the researchers on Wednesday, finding no evidence of "malice" in the publication.The litigation uncovered some errors in the study's data, but the judge said there was nothing to suggest the mistakes were obvious or deliberately ignored when the research was conducted.Johnson & Johnson plans appealJohnson & Johnson said it would appeal the ruling and seek a trial on its claims that the researchers made false statements about cosmetic talc and asbestos exposure.The three defendants are doctors who run pathology practices and have testified as expert witnesses for plaintiffs in asbestos-related litigation.Their lawyer, Liz Lockwood, said the ruling vindicated her clients and strongly affirmed the importance of protecting scientific speech.Questions over patient dataThe case also raised questions about the study's patient data.According to Reuters, Johnson & Johnson found that eight of the 75 patients in the 2020 study had also been included in a 2019 study by another researcher, despite the 2020 paper describing its participants as an entirely new group.Johnson & Johnson has also sued the researcher who published the 2019 study.The researchers were comparing anonymised data sets and information provided by lawyers, which sometimes made it difficult to identify duplicate patients, according to the ruling.Broader talc litigationJohnson & Johnson has faced extensive litigation over its talc products. The company sued the three researchers before agreeing to settle related cases for at least $5.5 billion.The ruling is a setback for Johnson & Johnson's defamation claims against the researchers, while the company's wider legal battles over its talc products continue.