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THE LANCET • Vol 355 • April 29, 2000 1523

SCIENCE AND MEDICINE

NEWS

FDA approves first drug in new class of antibiotics

On April 18, the US Food andDrug Administration (FDA)

approved Zyvox (linezolid) for thetreatment of bacteraemia caused byvancomycin-resistant Enterococcus fae-cium (VREF), hospital-acquiredpneumonia and complicated skininfections caused by meticillin-resis-tant Staphylococcus aureus (MRSA),and bacteraemia associated with com-munity-acquired pneumonia due topenicillin-susceptible Streptococcuspneumoniae. Developed by thePharmacia Corporation (Peapack,NJ, USA), Zyvox is a member of theoxazolidinones—the first new class ofantibiotic in 35 years.

The mechanism of action of Zyvoxis unique: it disrupts the bindingevent that brings the two subunits of

the bacterial ribosome together to initiate protein synthesis,thus blocking bacterialprotein production.

Wesley Mark Todd(Pharmacia), reports thatZyvox has already beenapproved and registeredin several countries inEurope and Asia andthat it may be approvedfor use in the UK soon.FDA approval was basedon clinical-trial data frommore than 4000 patientsin 44 countries. In a ran-domised, double-blind trial in which145 VREF patients were treated withZyvox (600 mg or 200 mg) every 12hours for 7–28 days, the overall cure

rate was 67% for the higherdose, and 52% for the lowerdose, says Todd. In a separatetrial, 400 patients with hospital-acquired pneumonia weretreated with either Zyvox(600 mg) or vancomycin(1000 mg) every 12 hours for7–28 days. According to Todd,the recovery rate in Zyvox-treated patients (57%) comparedwell with the 60% observed inthe vancomycin-treated group,and Zyvox achieved a slightlyhigher cure rate than van-comycin in patients with ventila-tor-associated pneumonia (47%

vs 40%). In a third trial of more than800 patients with com-plicated skin infections,90% of evaluablepatients recovered aftertaking Zyvox; oxacillinachieved a cure rate of85%.

“The development ofZyvox is one of the mostsignificant steps forwardin the past 30 years’ battle between man andmicrobes”, says AnthonyCoates (St George’sHospital Medical

School, London, UK). He points outthat “the incidence of infectionscaused by resistant strains ofStaphylococcus aureus and Enterococcusspecies has increased considerablyduring the past 10 years”. In a recentsurvey of serious blood infections inEngland and Wales, the incidence ofMRSA increased from 1·7% in 1990to 34% in 1998, and the incidence ofVREF rose from 6·3% in 1993 to24% in 1998. “Zyvox will make a bigdifference to clinical management”,observes Coates, but, more impor-tantly, “it also marks a shift in thepharmaceutical industry away fromthe ‘me-too’ adaptations of existingdrugs towards the development ofnew antibacterial strategies”.

Kathryn Senior

Oral infection with human papillomavirus 16 common in children

Buccal infection with humanpapillomavirus type 16 (HPV-

16), the HPV type most frequentlyassociated with cervical cancer, iscommon in young children, a UKstudy shows. According to theauthors, this finding suggests thatany vaccine against the virus mayneed to be given in infancy.

Jennifer Best (St Thomas’Hospital, London, UK) and col-leagues used two PCR techniques totest for HPV infection in buccalsamples from 267 healthy childrenaged 3–11 years. HPV-16 DNA wasdetected in 51·7% of samples by a

type-specific nested PCR assay,whereas HPV DNA was detected inonly 16·8% of samples tested with ageneric PCR (J Med Virol 2000; 61:70–75). The poor agreementbetween the two assays, Best sug-gests, may help to explain whysome groups have failed to detectHPV DNA in samples from chil-dren. “Our study indicates that dif-ferences in the sensitivity andspecificity of the PCR assays are atleast as important as populationdifferences.”

Because the prevalence of HPV-16 did not vary with age, Best sug-

gests that “infection becomesestablished in early life and persiststhereafter”. Infants can acquirepersistent HPV infection from theirmothers, but horizontal transmis-sion may also occur, she says.

Best is now investigating whethervertical transmission of high-riskHPVs induces HPV-specificimmune tolerance. “If tolerance isacquired, prophylactic vaccinesmay have to be offered at birth toprevent sexually acquired infectionlater in life”, she observes.

Dorothy Bonn

MRSA defeated?

Sci

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Pho

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New weapon against viral infectionsAt the 13th International Conference onAntiviral Research (16–21 April; Baltimore,MD, USA), Luis Schang and colleagues(University of Pennsylvania Medical Center,PA, USA) presented preliminary in-vitro workthat may lead to a class of antiviral drugthat blocks viral replication by inhibiting hostcyclin-dependent kinases (CDKs). Manyviruses use CDKs to replicate, and byblocking CDK activity, Schang andcollaborators have been able to blockreplication of herpes simplex virus types 1and 2 and human cytomegalovirus, withoutdamaging host cells.