Shares in Merck & Co have risen on the decision by a US judge to declare a mistrial in the first liability case to reach the courts linking the firm’s osteoporosis drug Fosamax to osteonecrosis of the jaw.

A mistrial was declared by US District Court Judge John Keenan regarding the case of Shirley Boles, a 71-year-old Florida woman who blamed her dental and jaw problems on Fosomax (alendronate) and has been seeking damages in excess of $1 million. The decision was taken after “several days of deliberations by an eight-person jury” who could not reach a unanimous verdict.

Reports of the trial suggest that it was a lively affair and one juror had accused others of intimidation. It was alleged that chairs had been thrown and physical threats made.

Paul Strain, outside counsel for Merck, claimed that the plaintiff failed to prove her case, adding that notes presented to the judge and signed by seven of the eight jurors, stated that they “agree that there is no evidence of proof that Fosamax caused Ms.Boles injury”. He went on to say that “unfortunately, Ms Boles had medical problems that cause people to develop jaw problems, regardless of whether they were taking Fosomax”.

Specifically, Mr Strain noted that she had “significant periodontal disease and a history of smoking up to a pack of cigarettes a day, which can result in poor wound healing”. Bruce Kuhlik, Merck’s general counsel, added that “we will be prepared to defend this case again if a retrial is scheduled”, saying that “we continue to believe that the company provided appropriate and timely information about Fosamax to consumers and to the medical, scientific and regulatory communities”.

The company noted that this was the first of 899 cases which had been filed as of June 30, which include some 1,280 plaintiff groups. Fosamax has been a huge arner for Merck but second-quarter sales slumped 33% to $277 million, as the loss of patent protection in the USA takes a grip.