Mabvax Therapeutics Holdings Inc., of San Diego, said that Opko Health Inc., of Miami, approved the release of $3.5 million in funds held in escrow from a $11.7 million financing that Mabvax completed in April. Mabvax agreed to give Opko the right, until June 30, 2016, to nominate and appoint up to two additional members to the company's board of directors, subject to satisfaction of standard corporate governance practices and other requirements.