Table 3 RCTs investigating the role of OABs in elective colorectal surgery

Abis (2019) [10]

SELECT

NCT01740947

Phase III

Multicentric

Netherlands

Stopped at interim analysis (superiority not attainable)

455 patients

(762 planned)

All colorectal resections

OABs (colistin, tobramycin and amphotericin B) vs no preparation

MBP + OABs vs no preparation for left-sided and rectal resections

AL (primary outcome)

Infectious complications

(secondary outcome)

NS difference in AL (6.1 vs 9.7%, OR 0.61 CI 95%, 0.30–1.22)

Reduced infectious complications (14.9 vs 26.9%, OR 0.47, CI 95% 0.29–0.76 at the multivariable analysis)

Koskenvuo (2019) [11]

MOBILE

NCT02652637

Phase III

Multicentric

Finland

Completed

396 patients

All colorectal resections

MBP + OABs (neomycin and metronidazole) versus no bowel preparation

SSIs (primary outcome)

AL, reoperation rate (secondary outcomes)

NS difference in SSIs (7 vs 11%, OR 1·65, 95% CI 0·80–3·40; p = 0·17), AL (4 vs 4%), reoperation rate (8 vs 7%)

Schardey (2020) [12]

-

-

Phase III

Monocentric

Germany

Stopped at interim analysis

(ethical reasons)

80 patients (280 planned)

Only rectal resections

MPB + OABs (polymyxin B, tobramycin, vancomycin, and amphotericin B) versus MBP + placebo (+ amphotericin B)

AL (primary outcome)

Infectious complications (secondary outcome)

Reduced leak in the MPB + OABs group

(5% versus 20%, p = 0.0425)

NS difference for infectious complications

Basany(2020) [13]

ORALEV

NCT02505581

Phase III multicentric

Spain

Completed

536 patients

Only colic resections (no rectal resections)

OABs (ciprofloxacin + metronidazole) vs no OABs

SSIs

Reduced SSIs in the OAB group (5% vs 11%, p = 0.013). Organ/space SSIs similar (1.9% vs 2.6%, p = NS)

ORALEV2

NCT04161599

Phase III multicentric

International

Recruiting

686 patients planned

MBP + OABs vs. OABs alone

SSIs

Ongoing