Nevirapine

Nevirapine
Systematic (IUPAC) name
11-cyclopropyl-4-methyl-5,11-dihydro-6H- dipyrido[3,2-b:2′,3′-e][1,4]diazepin-6-one
Clinical data
Trade names Viramune
AHFS/Drugs.com monograph
MedlinePlus a600035
  • B: (USA)
Oral
Pharmacokinetic data
Bioavailability 93% ± 9%
Metabolism Hepatic
Half-life 45 hours
Excretion Renal: <6% (Parent drug)
Biliary <5% (Parent drug)
Identifiers
129618-40-2 Yes
J05AG01
PubChem CID 4463
DrugBank DB00238 Yes
ChemSpider 4308 Yes
UNII 99DK7FVK1H Yes
KEGG D00435 Yes
ChEMBL CHEMBL57 Yes
NIAID ChemDB 001856
Chemical data
Formula C15H14N4O
266.888 g/mol
 Yes (what is this?)  (verify)

Nevirapine (NVP), also marketed under the trade name Viramune (Boehringer Ingelheim), is a non-nucleoside reverse transcriptase inhibitor (NNRTI) used to treat HIV-1 infection and AIDS.

As with other antiretroviral drugs, HIV rapidly develops resistance if nevirapine is used alone, so recommended therapy consists of combinations of three or more antiretrovirals.

It is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a basic health system.[1]

Medical uses

Nevirapine in triple combination therapy has been shown to suppress viral load effectively when used as initial antiretroviral therapy (i.e., in antiretroviral-naive patients).[2] Some clinical trials have demonstrated comparable HIV suppression with nevirapine-based regimens to that achieved with protease inhibitors (PIs)[3][4] or efavirenz.[5] Although concerns have been raised about nevirapine-based regimens in those starting therapy with high viral load or low CD4 count, some analyses suggest that nevirapine may be effective in these patients.[5]

Nevirapine may also form a useful component of salvage regimens after virological failure, usually in combination with one or more PIs as well as nRTIs, especially in those who have not previously taken an NNRTI.

Preventing mother-to-child transmission

A single dose of nevirapine given to both mother and child reduced the rate of HIV transmission by almost 50% compared with a very short course of zidovudine (AZT) prophylaxis, in a clinical trial in Uganda.[6] A subsequent study in Thailand showed that prophylaxis with single-dose nevirapine in addition to zidovudine is more effective than zidovudine alone.[7] These and other trials have led the World Health Organization to endorse the use of single-dose nevirapine prophylaxis in many developing world settings as a cost-effective way of reducing mother-to-child transmission. However, in the United States the Ugandan study was deemed flawed [8] and as of 2006 the FDA has not approved of such nevirapine prophylaxis.[9] However,supporters of HIVNET 012 experiment argued that the flaws in this experiment were largely due to bureaucratic incompetence, while the findings regarding the safety and efficacy of single-dose nevirapine from this study were scientifically solid and too important to discard. [10] Moreover, it was argued that holding African researchers who operated under resource-poor situations to the same moral and procedural standards to their Western counterparts was unrealistic, and would further marginalize African researchers' role in the science community and impede the progress of African science.[11]Another clinical trial, Using Nevirapine to Prevent Mother-to-Child HIV Transmission During Breastfeeding is scheduled for completion in March 2011.[12]

A major concern with this approach is that NNRTI resistance mutations are commonly observed in both mothers and infants after single-dose nevirapine,[13] and may compromise the response to future NNRTI-containing regimens.[14] A short course of maternal zidovudine/lamivudine is recommended by the U.S. Public Health Service Task Force to reduce this risk.[15]

Adverse effects

The most common adverse effect of nevirapine is the development of mild or moderate rash (13%).[16][17] Severe or life-threatening skin reactions have been observed in 1.5% of patients, including Stevens–Johnson syndrome, toxic epidermal necrolysis and hypersensitivity.[16]

Nevirapine may cause severe or life-threatening liver toxicity, usually emerging in the first six weeks of treatment.[16][18] In 2000, the U.S. Food and Drug Administration issued a black box label on nevirapine, warning that it could cause severe liver damage, including liver failure.[19] Unacceptably high risk of serious liver symptoms in certain patient groups (women with CD4 count >250 and men >400)[5][20] has led the U.S. DHSS to recommend the restriction of nevirapine use to those at lower risk, unless the benefit to the patient clearly outweighs the risk;[18] although in the 2NN study which found these CD4 limits, the effect was seen only in patients recruited from Thailand. More recent studies on the use of Nevirapine in people with higher CD4 cell counts have come to the following conclusion: Treatment-experienced patients who start NVP-based combination therapy with low pre–ART and high current CD4 cell counts and an undetectable VL have a similar likelihood for discontinuing NVP therapy because of hypersensitivity reactions (HSRs), compared with treatment-naive patients with low CD4 cell counts. This suggests that NVP-based combination therapy may be safely initiated in such patients. However, in similar patients with a detectable VL, it is prudent to continue to adhere to current CD4 cell count thresholds.[21] The U.S. Public Health Service Task Force advocates caution in the use of nevirapine in pregnancy due to toxicity issues, which may be exacerbated during pregnancy.[15]

Drug interactions

Significant lowering of nevirapine levels occurs with the anti-tuberculosis drug, rifampicin, and the drugs should not be administered together.[16]

Nevirapine is an inducer of cytochrome P450 isoenzymes CYP3A4 and CYP2B6. It reduces the levels of several co-administered drugs including the antiretrovirals efavirenz, indinavir, lopinavir, nelfinavir and saquinavir, as well as clarithromycin, ketoconazole, forms of hormonal contraception, and methadone.[16]

Mechanism of action

Nevirapine shown in ball and stick structure.

Nevirapine falls in the non-nucleoside reverse transcriptase inhibitor (NNRTI) class of antiretrovirals.[22] Both nucleoside and non-nucleoside RTIs inhibit the same target, the reverse transcriptase enzyme, an essential viral enzyme which transcribes viral RNA into DNA. Unlike nucleoside RTIs, which bind at the enzyme's active site, NNRTIs bind allosterically at a distinct site away from the active site termed the NNRTI pocket.

Nevirapine is not effective against HIV-2, as the pocket of the HIV-2 reverse transcriptase has a different structure, which confers intrinsic resistance to the NNRTI class.[23]

Resistance to nevirapine develops rapidly if viral replication is not completely suppressed.[2] The most common mutations observed after nevirapine treatment are Y181C and K103N, which are also observed with other NNRTIs.[16][24] As all NNRTIs bind within the same pocket, viral strains which are resistant to nevirapine are usually also resistant to the other NNRTIs, efavirenz and delavirdine. However, second generation NNRTIs like rilpivirine and etravirine are effective in treatment for HIV strains resistant to nevirapine and other first generation drugs in that same class.



Synthesis

Nevirapine can be synthesized from two pyridine derivatives. The reaction of cyclopropylamine with the dichloroamide, shown in step 2, is hazardous due to the potential for rapid pressure build up and a large exotherm.

Nevirapine synthesis:[25]

History

Nevirapine was discovered by Hargrave et al. at Boehringer Ingelheim Pharmaceuticals, Inc., one of the Boehringer Ingelheim group of companies. It is covered by U.S. Patent 5,366,972 and corresponding foreign patents. Nevirapine was the first NNRTI approved by the U.S. Food and Drug Administration (FDA). It was approved June 21, 1996 for adults and September 11, 1998 for children. It was also approved in Europe in 1997.

AIDS in Africa

Former U.S. President George W. Bush's PEPFAR funding of $500 million to help combat the African AIDS epidemic included nevirapine, among other medications and programs.

References

  1. ↑ "WHO Model List of EssentialMedicines". World Health Organization. October 2013. Retrieved 22 April 2014.
  2. ↑ 2.0 2.1 Montaner JS, Reiss P, Cooper D (Mar 1998). "A randomized, double-blind trial comparing combinations of nevirapine, didanosine, and zidovudine for HIV-infected patients: the INCAS Trial. Italy, The Netherlands, Canada and Australia Study". JAMA 279 (12): 930–7. doi:10.1001/jama.279.12.930. PMID 9544767.
  3. ↑ van Leeuwen R, Katlama C, Murphy RL (May 2003). "A randomized trial to study first-line combination therapy with or without a protease inhibitor in HIV-1-infected patients". AIDS 17 (7): 987–99. doi:10.1097/00002030-200305020-00007. PMID 12700448.
  4. ↑ Podzamczer D, Ferrer E, Consiglio E. "A randomized clinical trial comparing nelfinavir or nevirapine associated to zidovudine/lamivudine in HIV-infected naive patients (the Combine Study)". Antiviral Ther 7: 81–90.
  5. ↑ 5.0 5.1 5.2 van Leth F, Andrews S, Grinsztejn B (Mar 2005). "The effect of baseline CD4 cell count and HIV-1 viral load on the efficacy and safety of nevirapine or efavirenz-based first-line HAART". AIDS 19 (5): 463–71. doi:10.1097/01.aids.0000162334.12815.5b. PMID 15764851.
  6. ↑ Guay LA, Musoke P, Fleming T (Sep 1999). "Intrapartum and neonatal single-dose nevirapine compared with zidovudine for prevention of mother-to-child transmission of HIV-1 in Kampala, Uganda: HIVNET 012 randomised trial". Lancet 354 (9181): 795–802. doi:10.1016/S0140-6736(99)80008-7. PMID 10485720.
  7. ↑ Lallemant M, Gonzague Jourdain G, Sophie Le Coeur S, et al. (2004) Single-Dose Perinatal Nevirapine plus Standard Zidovudine to Prevent Mother-to-Child Transmission of HIV-1 in Thailand. N Engl J Med 351: 217-28
  8. ↑ The HIVNET 012 Study and the Safety and Effectiveness of Nevirapine in Preventing Mother-to-Infant Transmission of HIV, http://www3.niaid.nih.gov/news/newsreleases/2004/hivnet012.htm
  9. ↑ Celia Farber, "Out of Control: AIDS and the Corruption of Science" http://www.harpers.org/archive/2006/03/0080961
  10. ↑ Crane, J 2010, 'Adverse events and placebo effects: African scientists, HIV, and ethics in the 'global health sciences, Social Studies Of Science, 40, 6, pp. 843-870 http://sss.sagepub.com.ezp.lib.unimelb.edu.au/content/40/6/843.full.pdf+html
  11. ↑ Lock, M. & Nguyen, V 2010, an Anthropology of Biomedicine, Malden, Wiley-Blackwell.
  12. ↑ http://clinicaltrials.gov/show/NCT00074412
  13. ↑ Johnson JA, Li JF, Morris L (Jul 2005). "Emergence of drug-resistant HIV-1 after intrapartum administration of single-dose nevirapine is substantially underestimated". J Infect Dis. 192 (1): 16–23. doi:10.1086/430741. PMID 15942889.
  14. ↑ Jourdain G, Ngo-Giang-Huong N, Le Coeur S (Jul 2004). "Intrapartum exposure to nevirapine and subsequent maternal responses to nevirapine-based antiretroviral therapy". N Engl J Med. 351 (3): 229–40. doi:10.1056/NEJMoa041305. PMID 15247339.
  15. ↑ 15.0 15.1 Recommendations for Use of Antiretroviral Drugs in Pregnant HIV-1-Infected Women for Maternal Health and Interventions to Reduce Perinatal HIV-1 Transmission in the United States. Public Health Service Task Force. (November 17, 2005) (Available for download from AIDSInfo)
  16. ↑ 16.0 16.1 16.2 16.3 16.4 16.5 Viramune (nevirapine) tablets; Viramune (nevirapine) oral suspension prescribing information
  17. ↑ "Facts sheet from the AIDS Treatment Data Network". Retrieved 2006-01-16.
  18. ↑ 18.0 18.1 DHHS panel. Guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents (May 4, 2006). (Available for download from AIDSInfo)
  19. ↑ Viramune (nevirapine) letter (November 2000)
  20. ↑ Stern JO, Robinson PA, Love J, Lanes S, Imperiale MS, Mayers DL (2003). "A comprehensive hepatic safety analysis of nevirapine in different populations of HIV-infected patients". J Acquir Immune Defic Syndr 34 (Suppl 1): S21–S33. doi:10.1097/00126334-200309011-00005.
  21. ↑ Wit FW, Kesselring AM, Gras L (Mar 2008). "Discontinuation of nevirapine because of hypersensitivity reactions in patients with prior treatment experience, compared with treatment-naive patients: the ATHENA cohort study". Clin Infect Dis. 46 (6): 933–40. doi:10.1086/528861. PMID 18271750.
  22. ↑ Patel SS, Benfield P (Oct 1996). "New drug profile: nevirapine". Clinical Immunotherapeutics 6 (4): 307–317.
  23. ↑ Ren J, Bird LE, Chamberlain PP, Stewart-Jones GB, Stuart DI, Stammers DK (Oct 2002). "Structure of HIV-2 reverse transcriptase at 2.35-A resolution and the mechanism of resistance to non-nucleoside inhibitors". Proc Natl Acad Sci USA. 99 (22): 14410–5. doi:10.1073/pnas.222366699. PMC 137897. PMID 12386343.
  24. ↑ Conway B, Wainberg MA, Hall D (Jul 2001). "Development of drug resistance in patients receiving combinations of zidovudine, didanosine and nevirapine". AIDS 15 (10): 1269–74. doi:10.1097/00002030-200107060-00008. PMID 11426071.
  25. ↑ Hargrave, K. D.; Proudfoot, J. R.; Grozinger, K. G.; Cullen, E.; Kapadia, S. R.; Patel, U. R.; Fuchs, V. U.; Mauldin, S. C.; Vitous, J. (1991). "Novel non-nucleoside inhibitors of HIV-1 reverse transcriptase. 1. Tricyclic pyridobenzo- and dipyridodiazepinones". Journal of Medicinal Chemistry 34 (7): 2231. doi:10.1021/jm00111a045.