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No Infection Dx for Abx; Combo Tx for MRSA Scores; CMV Vax Promising

— Presentations, late-breaking clinical trials cover a variety of topics

Ƶ MedicalToday

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SAN FRANCISCO -- Researchers presented the latest results on newer therapies, and some new ways at looking at older therapies at several presentations and late-breaking clinical trials here.

First, one study showed that a total of 46% of outpatient antibiotic prescriptions were written without an infection-related diagnosis, and 20% were written outside of in-person visits, reported Jeffrey A. Linder, MD, of Northwestern University Feinberg School of Medicine in Chicago.

The were presented at IDWeek, with joint sponsorship by the (IDSA), the (PIDS), the (SHEA), and the (HIVMA).

The researchers examined over 500,000 antibiotic prescriptions that were classified into three groups:

  • Infection-related, for prescriptions associated with ≥1 ICD-10 code that could signify infection
  • Non-infection related, for prescriptions associated with ≥1 ICD-10 code that does not signify infection
  • Those associated with no diagnosis

Patients were a median age of 43, 60% were women, and three-quarters were white, while over half of the clinicians were women and over 60% were attending physicians. Penicillins (30%), macrolides (23%), and cephalosporins (14%) were the most commonly prescribed antibiotics, the authors said.

In addition to the 54% of prescriptions related to infection diagnosis, 29% were non-infection related and 17% were associated with no diagnosis.

"At busy clinics, sadly the most efficient thing to do is just call in an antibiotic prescription. We need to dig into the data more, but we believe there is a lot of antibiotic prescribing for colds, the flu, and non-specific symptoms such as just not feeling well, none of which are helped by antibiotics," Linder said in a statement.

Daptomycin Plus Fosfomycin More Effective Than Daptomycin Monotherapy for MRSA Tx

Also on the subject of antibiotics, a reported by Miquel Pujol, MD, of Hospital de Bellvitge, L'Hospitalet llobregat, in Spain, found that a higher proportion of patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia who were treated with daptomycin plus fosfomycin were associated with successful outcomes at the test-of-cure visit, as well as treatment success at 7 days, compared with patients treated with daptomycin monotherapy.

The authors said that this combination therapy demonstrated "synergistic and bactericidal effects" in the treatment of MRSA bacteremia, but that there was a lack of data in humans. The team randomized 155 patients -- 74 received combination therapy and 81 received monotherapy.

Primary outcomes were treatment success at test-of-cure visit, 6 weeks after therapy (54.1% combination therapy versus 42.0% monotherapy patients, absolute difference 12.1%, 95% CI 0%-27.0%) and treatment success at 7 days, which was defined as "alive at day 7 and clearance of bacteremia without relapse from 8 to 90 days after infection" (93.2% versus 76.5%, absolute difference 16.7%, 95% CI 5.4%-27.7%).

The authors also noted that combination therapy was associated with lower rates of microbiologic failure at the test-of-cure visit, though combination therapy was also linked with a non-significantly higher rate of "adverse events due to study medication leading to treatment failure and discontinuation of therapy" compared with monotherapy, Pujol and colleagues wrote.

First Human Trial of Cytomegalovirus Vax Candidate Shows Promise

A candidate enveloped virus-like particle cytomegalovirus vaccine was safe and immunogenic in healthy seronegative adults, according to a presented by Soren Gantt, MD, of the University of British Columbia in Vancouver, Canada.

In this phase I trial, healthy seronegative adults ages 18 to 40 were randomized to receive a 0.5 μg, 1 μg, or 2 μg dose with alum, a 1 μg gB without alum, or placebo on days 0, 56, and 168.

Among the 128 participants, the most common adverse events were pain and headache, although no serious adverse events or withdrawals occurred, Gantt and colleagues reported. They found "dose-dependent boosting of [neutralizing antibody] titers" after doses 2 and 3, with the highest titers among participants who received the adjuvanted 2 μg dose.

The authors concluded that this supports further development of this vaccine candidate against cytomegalovirus, "the most common cause of congenital infection," they said.

Disclosures

Linder and colleagues disclosed no conflicts of interest.

Pujol and colleagues disclosed no conflicts of interest.

Gantt disclosed relationships with VBI Vaccines, which provided institutional support for the clinical trial; other co-authors disclosed being employees of VBI Vaccines.

Primary Source

IDWeek

Linder JA, et al “Non-visit based and non-infection related ambulatory antibiotic prescribing” IDWeek 2018; Abstract 1632.

Secondary Source

IDWeek

Pujol M, et al “Daptomycin plus fosfomycin versus daptomycin monotherapy for methicillin-resistant Staphylococcus aureus bacteremia: A multicenter, randomized, clinical trial” IDWeek 2018; Abstract LB3.