<p>Shareholder Chris Larson, of San Diego, has filed the suit in Montgomery County's circuit court in Maryland in an attempt to block the deal and force the board to obtain the highest possible value for shareholders. If successful, the deal would be declared invalid and unenforceable.<br /><br />The suit alleges that MedImmune spent a substantial effort tailoring the acquisition to meet the specific needs of AstraZeneca, and failed to tell stockholders the real value of the company.<br /><br />In April, UK-based AstraZeneca agreed to acquire US biotech Medlmmune for $58 per share, valuing the company at $15.6 billion. MedImmune said that it believes the claims asserted by the plaintiff are without merit and intends to defend the action vigorously.</p>