Spencer Cox, an AIDS activist whose work with a cadre of lay scientists helped push innovative antiretroviral drugs to market, creating the first effective drug protocols to combat the syndrome, died on Tuesday in Manhattan. He was 44.

His death of AIDS-related causes at the Allen Hospital in Upper Manhattan was confirmed by his brother, Nick.

Mr. Cox was a prominent voice in the fight against AIDS for more than two decades. After three years as a student at Bennington College in Vermont, he moved to New York. By 1989, at age 20, he had joined the AIDS Coalition to Unleash Power, better known as Act Up, the organization devoted to pushing government and private industry, often with demonstrations, sit-ins and other tactics, to dedicate more resources for AIDS treatment and prevention.

In 1992, he was among the Act Up members who formed the Treatment Action Group, known as TAG, to focus on accelerating treatment research.