Don, I am 6 yrs poz, treatment naive and last counts 200 plus and 200,000 plus. VL down from the previous three month test showing 500,000 plus. I suspect I may have been reinfected. Genotype done on the advent of therapy showed higly resistant to most drugs, except nNRTI's. Among the things being considered is T20. I know the resistance panel doesn't tell me about possible resistance to T20. I understand I can be tested for that. I live in Canada and I doubt we have that facility yet but am looking into that. Where in the US can this be done? Do you recommend it in my case? Can you recommend a lab? How much does it generally cost? Have you heard of GenoSure? I can't see the point in using T20 if the evidence suggests otherwise. Thanks for your help. Mike

Mike,

Current phenotypes and genotypes do not include testing for Fuzeon (T20). There is no cross resistance between NRTIs/NNRTIs/PIs and Fuzeon. So if you were resistant to all these drugs, you should expect activity from Fuzeon (but you would never want to go on Fuzeon as the only active drug; you need to use it in combination with at least a couple other active agents). If someone had a sexual or IVDU exposure to an individual with Fuzeon, they would likely inherit Fuzeon resistance as well. All this being said, if you were highly resistant to most drugs except NRTIs, I'd expect Fuzeon to be potentially active drug for you. If you were reinfected and your contact had Fuzeon resistance, you might not respond.

As far as I know, there are only two labs offering Fuzeon resistance testing: LabCorp and Virologic. I've not seen any Insurance companies reimburse for this test yet. I know of a couple of people who have paid for the test; I believe the cost is $400-600 for the Fuzeon panel). I have one patient who recently screened for a CCR5 inhibitor study. Because he has been on Fuzeon in the past, the study sponsor covered the cost of a genotype to look for Fuzeon resistance. Considering the cost of Fuzeon, you'd think resistance testing for this drug would be covered in an effort to make cost-effective decisions. I'm not sure how things are covered in the Canadian healthcare system.

I think the odds are in your favor that you are not resistant to Fuzeon. If you really think you were reinfected AND this person has a strong possibility of being resistant to Fuzeon, it might be worth the while to check a resistance test.

--dk