CRE Combination versus monotherapy.pdf
CE: Tripti; QCO/310607; Total nos of Pages: 6;
Combination versus monotherapy Carrara et al.
meropenem–vaborbactam) will also contribute to
significantly modify the approach to treatment of
CRE infections. The efficacy and safety of imipenem–relebactam versus imipenem–colistin have
been compared in a phase 3 RCT in patients with
imipenem-resistant bacterial infections. With the
limitation of the small sample size (31 patients
enrolled, randomized in a 2 : 1 fashion), 28-day
all-cause mortality was 30% in the colistin–imipenem group and 9.5% in the imipenem–relebactam
group with a 17.3% adjusted difference and a wide
confidence interval (adjusted difference:17.3%, 95%
CI 46.4 to 6.7) . A phase 3 multicenter openlabel RCT compared the efficacy of meropenem–
vaborbactam to the best available treatment in 77
patients with selected serious infections because of
CRE. The study is complete, and results are expected
to be published soon (NCT02168946).
Combination therapy for the treatment of CRE infections is supported only by low-quality evidence,
derived mainly from in-vitro and observational studies. Both aminoglycosides and tigecycline are important resources in the armamentarium against CRE
infections. Within the strict limitations of the scant
available evidence, tigecycline-containing combinations are associated with lower mortality than tigecycline alone, but no specific data are available on
which drug should be included in the combination.
Conversely, aminoglycoside-containing combinations do not provide better outcomes than aminoglycoside monotherapy. The combination of CEF–
AVI and colistin is not supported by in-vitro studies,
and no clinical studies evaluating this combination
have been conducted. The combination of avibactam
with aztreonam provides in-vitro coverage against
MBL producers, but this combination requires further evaluation in the clinical practice. Further studies are also urgently needed to better understand the
role of fosfomycin, alone or in combination with
colistin, specifically to assess whether the enhanced
bactericidal effect of combination therapy translates
into improved clinical outcomes and reduced resistance development. Results from recently published
RCTs pooled together with a similar ongoing RCT
should finally shed some light on the longstanding
debate about the added value of this combination.
Newly developed drugs constitute a valuable resource
in the fight against antimicrobial resistance;
however, the potential in-vitro coverage against
KPC should be supported by well designed trials with
adequate sample size.
In conclusion, in an era of increasing antibiotic resistance, combination therapy should be
considered only after its benefit for clinical outcomes has been adequately proven. Future trials
should test specific combination schemes to assess
whether the hypothetical benefit outweighs the risk
of more side effects and the unclear impact on
We thank Anne McDonough, a professional medical
writer for editorial assistance. She was partly supported
by WHO Priority pathogen list project, grant number
Financial support and sponsorship
There are no financial support and sponsorship.
Conflicts of interest
There are no conflicts of interest.
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