Curiosity

[Alehax]

What do you think about the new drug Rifasutenizol ?

[Helico_expert]

Rifasutenizol is an interesting compound. It is a fixed-dose combination of rifabutin and metronidazole, designed to hit the bacterium through two distinct targets simultaneously: rifabutin inhibits the β-subunit of bacterial DNA-dependent RNA polymerase (encoded by rpoB), while metronidazole is reduced under low-oxygen conditions and releases toxic metabolites that damage bacterial DNA.

Rifabutin is primarily reserved for mycobacterial infections such as tuberculosis, so widespread use could theoretically drive cross-resistance in M. tuberculosis. However, rifabutin does not share resistance with clarithromycin, metronidazole or levofloxacin in H. pylori.

Clinical data from China look promising. In a phase 2b trial, a triple regimen of 400 mg rifasutenizol plus rabeprazole and amoxicillin twice daily for 14 days achieved a 95% eradication rate (95% CI 74–100), and a 7-day course of 600 mg three times daily reached 100% (69–100). The high success rates may partly reflect the low baseline use of rifabutin in China, meaning pre-existing resistance is rare. That said, metronidazole resistance in China is already very high, pooled data show roughly 78% (73–84%) in 2016–2020, and over 90% in some regions, so the metronidazole component of rifasutenizol may contribute less than the rifabutin component in many patients.

Finally, H. pylori is not as intrinsically sensitive to rifabutin as it is to amoxicillin, tetracycline or furazolidone. Resistance to rifabutin can emerge readily through rpoB mutations, much like resistance to clarithromycin, metronidazole or fluoroquinolones. Therefore, while rifasutenizol appears effective, it should be used judiciously, most likely as a rescue or second-line option rather than first-line therapy.