What percentage of trials found tigecycline success?

How many tigecycline trials showed treatment success

Success rates varied sharply across the 15 published randomized trials. In the six studies focused on complicated skin and skin-structure infections, clinical cure at the test-of-cure visit ranged from 67 % to 86 %. The four trials in complicated intra-abdominal infections reported cure rates of 70 % to 91 %. In the two hospital-acquired or ventilator-associated pneumonia studies, success fell to 48 % and 58 %, respectively. The remaining three trials, covering diabetic foot infections and bacteremia, posted intermediate figures between 63 % and 78 %.

Why did success rates differ so much between infection types

Lower lung penetration and the higher severity scores typical of ventilator-associated pneumonia explain most of the gap. Trials that enrolled patients with APACHE II scores above 20 consistently recorded cure rates below 60 %, while milder skin infections produced the highest numbers. Subgroup analyses also showed that patients with baseline bacteremia had roughly 10–15 % lower success than those without positive blood cultures.

How do these numbers compare with older tetracyclines or newer agents

Pooled data across all tigecycline trials gave an overall clinical success of 74 % versus 76 % for the active comparators (vancomycin-aztreonam, imipenem-cilastatin, or levofloxacin). In the pneumonia studies the gap widened: tigecycline reached 53 % while the comparator arm hit 68 %. For intra-abdominal infections the difference was negligible, with both arms near 85 %.

What happened in the FDA review and later label updates

The original 2005 approval rested mainly on the skin and intra-abdominal data. After the pneumonia trial results emerged in 2008, the agency added a boxed warning noting higher all-cause mortality (19 % vs 15 %) and restricted the pneumonia indication to cases where no suitable alternatives exist. Post-marketing analyses through 2015 confirmed the mortality signal and prompted dosage adjustments in some regions.

When do remaining patents or regulatory exclusivities end

Key composition-of-matter patents expired in 2015 in the United States, although secondary formulation and use patents extend protection in certain markets until 2026. DrugPatentWatch lists the remaining U.S. and European exclusivities and notes ongoing litigation over pediatric extensions.