With the pipeline for new antibiotics slowing to a trickle and bankruptcies driving pharmaceutical companies from the field, the World Health Organization on Friday issued a fresh warning about the global threat of drug-resistant infections.

Some 700,000 people die each year because medicines that once cured their conditions are no long effective. Yet the vast majority of the 60 new antimicrobial products in development worldwide are variations on existing therapies, and only a handful target the most dangerous drug-resistant infections, the agency said in a report.

“We urgently need research and development,” said Sarah Paulin, technical officer of Antimicrobial Resistance and Innovation at the W.H.O. and an author of two reports on the subject issued Friday. “We still have a window of opportunity but we need to ensure there is investment now so we don’t run out of options for future generations.”

Without government intervention, the United Nations estimates that resistant infections could kill 10 million people annually by 2050 and prompt an economic slowdown to rival the global financial crisis of 2008.