Fidaxomicin for Clostridium difficile
C. difficile is a bacteria part of our normal bowel flora, but when certain antibiotics (namely clindamycin) wipe out the other healthy organisms, C. diff’s growth is left unchecked. C. diff colitis is something I saw all the time in February while working on the gastroenterology service at St. Luke’s, so I learned quite a bit about it’s presentation – crampy abdominal pain, profuse and watery diarrhea, pseudomembraneous colitis visualized by colonoscopy, high leukocytosis, and in the very severe/late stages, toxic megacolon.
Oral vancomycin and metronidazole have routinely been used to treat this form of colitis, the former being better for more severe cases; however, as of May 27th, the FDA has approved a new antibiotic – Dificid (fidaxomicin). Dificid’s true beauty is in the fact that it, more or less, is selective for C. difficile thereby leaving healthy intestinal flora minimally disturbed. While Optimer Pharmaceuticals ascertains the “cure rate” of Dificid to be similar to that of vancomycin, it’s the recurrence rate they should rightfully herald as an achievement.
The following table shows the recurrence rate of C. diff in patients treated with fidaxomicin versus Vancocin© (vancomycin):
|Fidaxomicin (200mg bid)||Vancocin (125mg qid)|
|In-patient||17.9% (19/106)||26.1% (29/111)|
|Out-patient||8.6% (9/105)||21.8% (24/110)|
|<65 y/o||9.5% (12/126)||18.6% (22/118)|
|>/=65 y/o||18.8% (16/85)||30.1% (31/103)|
|BI (NAP1/027) Strain||25.0% (11/44)||24.1% (13/54)|
|OVERALL||13.3% (28/211)||24.0% (53/221)|
Source: Optimer Pharmaceuticals, Inc.
Cost will likely be an obstacle in the beginning, but it’s good to see a more efficacious drug being approved by the FDA for a relatively common and potentially fatal disease – Clostridium difficile colitis. 🙂