Delamanid, a new 6-nitro-2,3-dihydroimidazo[2,1-b]oxazole for the management of tuberculosis resistant to at least isoniazid and rifampicin

The Current Status of O-Heterocycles: A Synthetic and Medicinal Overview

O-Heterocycles have been explored in the field of medicinal chemistry for a long time, but their significance has not been duly recognised and they are often shunned in favour of N-heterocycles. The design of bioactive molecules for nearly every pathophysiological condition is primarily focused on novel N-heterocycles. The main reasons for such bias include the ease of synthesis and possible mimicking of physiological molecules by N-heterocycles. But considering only this criterion rarely provides breakthrough molecules for a given disease condition, and instead the risks of toxicity or side effects are increased with such molecules. On the other hand, owing to improved synthetic feasibility, O-heterocycles have established themselves as equally potent lead molecules for a wide range of pathophysiological conditions. In the last decade there have been hundreds of reports validating the fact that equally potent molecules can be designed and developed by using O-heterocycles, and these are also expected to have comparably low toxicity. Even so, researchers tend to remain biased toward the use of N-heterocycles over O-heterocycles. Thus, this review provides a critical analysis of the synthesis and medicinal attributes of O-heterocycles, such as pyrones, oxazolones, furanones, oxetanes, oxazolidinones, and dioxolonones, and others, reported in the last five years, underlining the need for and the advantages guiding researchers toward them.

Delamanid: a review of its use in patients with multidrug-resistant tuberculosis

Delamanid (Deltyba(®)), a nitroimidazo-oxazole derivative, is a new anti-tuberculosis (TB) drug which exhibits potent in vitro and in vivo antitubercular activity against drug-susceptible and -resistant strains of Mycobacterium tuberculosis. It is approved in several countries, including Japan and those of the EU, for use as part of an appropriate combination regimen in adults with multidrug-resistant tuberculosis (MDR-TB) when an effective treatment regimen cannot otherwise be composed due to resistance or tolerability. In a robust phase II trial in adult patients with MDR-TB, oral delamanid 100 mg twice daily for 2 months plus an optimized background regimen improved sputum culture conversion rates to a significantly greater extent than placebo. In a 6-month extension study, long-term (≤8 months) treatment with delamanid was associated with a higher incidence of favourable outcomes (i.e. cured or completed all treatment) than short-term (≤2 months) treatment, with an accompanying reduction inunfavourable outcomes as defined by the WHO (i.e. pre-specified proportion of TB-positive sputum cultures, death or treatment discontinuation for ≥2 months without medical approval). Delamanid was not associated with clinically relevant drug-drug interactions, including with antiretroviral drugs and those commonly used in treating TB. Delamanid was generally well tolerated in patients with MDR-TB, with gastrointestinal adverse events and insomnia reported most commonly. Although the incidence of QT interval prolongation was higher with delamanid-based therapy, it was not associated with clinical symptoms such as syncope and arrhythmia. In conclusion, delamanid is a useful addition to the treatment options currently available for patients with MDR-TB.

Long-term mortality assessment of multidrug-resistant tuberculosis patients treated with delamanid

Multidrug-resistant tuberculosis (MDR-TB) is a serious obstacle to TB control [1]. The disproportionately negative outcomes among patients with drug resistance reflect a strong global need to develop new anti-TB drugs [2, 3]. Delamanid is a novel anti-TB agent that has recently been approved for the management of MDR-TB patients [4]. Treatment of MDR-TB patients with delamanid in combination with an optimised background regimen for 2 months significantly improved 2-month sputum culture conversion (SCC) by ∼50%, in comparison to treatment with placebo plus an optimised background regimen [5]. Additionally, compared to ≤2 months of treatment, ≥6 months of treatment with delamanid plus an optimised background regimen was associated with higher favourable treatment outcomes (55.0% versus 74.5%) and significantly lower mortality (8.3% versus 1.0%, p<0.001) [6]. While early SCC is recognised as a biomarker in the development of anti-TB drugs [7–9], the impact of early SCC on long-term mortality in MDR-TB patients has only been assessed in retrospective cohort analyses [10–13]. Using updated prospective data from the delamanid development programme, we assessed the association between 2-month SCC and mortality in MDR-TB patients and expanded a previous analysis on the impact of long-term treatment with delamanid on mortality.

MDR-TB patients treated with 6 months or more of delamanid had significantly lower likelihood of mortalityhttp://ow.ly/HOv1d