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#169 Pre-Exposure Prophylaxis (PrEP): Are you PrEP’d for the future of HIV prevention?


CLINICAL QUESTION
QUESTION CLINIQUE
 In patients at higher risk of contracting HIV, can daily antiviral therapy prevent infection?

BOTTOM LINE
RÉSULTAT FINAL
 Tenofovir/emtricitabine (PrEP) once daily reduces the risk of HIV by ~50%, preventing infection for ~1 in 50 per year. A year of therapy costs ~$12,000 and ~1 in 34 develop nausea/vomiting due to the drug.   


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EVIDENCE
DONNÉES PROBANTES
 PrEP is tenofovir 300 mg (TDF) +/- emtricitabine 200 mg (FTC) once daily. 
  • Three systematic reviews1-3 with 6-15 Randomized Controlled Trials (RCTs), new HIV infection statistically significantly reduced:     
    • Meta-analysis (10 RCTs, 17,423 patients): 51% relative risk reduction (RRR).1 
      • Others2,3 similar. 
      • Event rates over ~1 year:2 2% PrEP versus 4% placebo, Number Needed to Treat (NNT)=50.  
      • Adherence matters: Adherence >70%, RRR=70% but adherence <40%, effect not significant.1   
  • Seven primary RCTs (total 18,582 patients): 
    • High-risk groups studied: Homosexual men (two RCTs);4,5 Heterosexual couples with one HIV positive (one RCT);6 Single heterosexuals –Africa (one RCT);7 IV drug-users –Thailand (one RCT);8 Women –Africa (two RCTs).9,10 
      • All similar with NNT=16-67 over ~1 year,4-8 except: 
      • Two RCTs of African women:9,10 No effect but adherence very low. 
        • Example: ≤30% had drug in serum when tested.10     
  • Other aspects: 
    • Condom use ~80% and generally similar between groups.4,6,7,10   
    • TDF effect likely similar to TDF+FTC,1 but TDF+FTC most studied.   
    • Adverse effects: Generally increased nausea/vomiting3 (example 8% versus 5%, NNH=34).8  
      • Serious adverse events not increased.4-10 
Context:   
  • CDC guidelines suggest PrEP (TDF+FTC) be considered if high risk of HIV infection.11   
  • Although cost is $12,000/year, PrEP can be cost effective.12   
  • Modeling study: Homosexual men contracting HIV annually:13   
    • 10.9% if no PrEP or condom use. 
    • ~3% if excellent PrEP or condom adherence.  
    • 0.9% if excellent PrEP and condom adherence. 
  • Unclear if PrEp increases risk behaviour:  
    • Most research suggests not,1 but one RCT found more PrEP users had multiple partners without condoms (21% versus 12%)5 and cohort study found 41% of men used condoms less.14 

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Author(s)
Auteur(s)
  • Corey Jefferies BScPharm
  • Daniel McKennitt MD MPH(c) CCFP
  • G. Michael Allan MD CCFP

1. Fonner VA, Dalglish SL, Kennedy CE, et al. AIDS. 2016; 30(12):1973-83.

2. Jiang J, Yang X, Ye L, et al. PLoS ONE. 2014; 9(2):e87674.

3. Okwundu CI, Uthman OA, Okoromah CAN. Cochrane Database Syst Rev. 2012; 7:CD007189.

4. Grant RM, Lama JR, Anderson PL, et al (iPrEx). N Engl J Med. 2010; 363:2587-99.

5. McCormack S, Dunn DT, Desai M, et al (PROUD). Lancet. 2016; 387:53-60.

6. Baeten JM, Donnell D, Ndase P, et al (Partners PrEP). N Engl J Med. 2012; 367:399-410.

7. Thigpen MC, Kebaabetswe PM, Paxton LA, et al (TDF2). N Engl J Med. 2012; 367:423-34.

8. Choopanya K, Martin M, Suntharasamai P, et al (Bangkok Tenofovir). Lancet. 2013; 381:2083-90.

9. Van Damme L, Corneli A, Ahmed K, et al (FEM-PrEP). N Engl J Med. 2012; 367:411-22.

10. Marrazzo JM, Ramjee G, Richardson BA, et al (VOICE). N Engl J Med. 2015; 372:509-18.

11. US Public Health Service. Preexposure prophylaxis for the prevention of HIV infection in the United States. CDC 2014. Available from: https://www.cdc.gov/hiv/pdf/prepguidelines2014.pdf. Last accessed July 2, 2016.

12. Gomez GB, Borquez A, Case KK, et al. PLoS Med. 2013; 10(3):e1001401.

13. Smith DK, Herbst JH, Rose CE. Sex Transm Dis. 2015; 42:88-92.

14. Volk JE, Marcus JL, Phengrasamy T, et al. Clin Infect Dis. 2015; 61:1601-3.

Authors do not have any conflicts of interest to declare.

Les auteurs n’ont aucun conflit d’intérêts à déclarer.