Delamanid (USAN, codenamed OPC-67683) is an experimental drug for the treatment of multi-drug-resistant tuberculosis. It works by blocking the synthesis of mycolic acids in Mycobacterium tuberculosis, the organism which causes tuberculosis, thus destabilising its cell wall. In phase II clinical trials, the drug was used in combination with standard treatments, such as four or five of the drugs ethambutol, isoniazid, pyrazinamide, rifampicin, aminoglycoside antibiotics, and quinolones. Healing rates (measured as sputum culture conversion) were significantly better in patients who additionally took delamanid. The European Medicines Agency (EMA) recommended conditional marketing authorization for delamanid in adults with multidrug-resistant pulmonary tuberculosis without other treatment options because of resistance or tolerability. The EMA considered the data show that the benefits of delamanid outweigh the risks, but that additional studies were needed on the long-term effectiveness.

• PA 824, a related drug