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Multidrug resistance - update from 2007
Sep 10, 2009


A phenotype resistance test showed multidrug resistance in May of 2006. This includes all the active ingredients of Atripla.

A few months later, I had genotype and phenotype tests repeated and they showed minimal resistance.

In June 2007, after a viral load spike, my doctor allowed me to try Atripla. Within 3 months I was undetectable and have stayed undetectable for the last 2 years and counting.

If we had taken the initial resistance test as fact, I would never have tried the amazingly simple and well-tolerated Atripla.

Mistakes can happen in any test, but do you think it is worthwhile to repeat resistance testing, as a standard procedure, immediately after getting an unfavorable result? The time after that first resistance test up until the regimen proved successful were much more difficult than dealing with the initial diagnosis itself, and I can't help but wonder how many people are on treatment that is unnecessarily complex and harsh because of following the standard procedure of resistance testing. I know now there are more treatment options than just a few years ago, but for a population looking at lifelong treatment, the unnecessary elimination of effective treatment options could be a problem several years down the road when it may be necessary to switch.

Thanks for your time. I greatly appreciate your dedication and support to the community.


Response from Dr. Sherer

There are many important considerations in the story that you tell, but I would not conclude that repeat resistance tests are always needed when adverse results are received. Better to conclude that there are MANY good reasons to quickly repeat resistance tests, such as discordant results between a genotype and phenotype test (In your case, you didn't mention that a genotype was done in May, 2006), or wildly unexpected or unusual results. Because it is somewhat unusual to find complete resistance to all three components of Atripla in an untreated patient, if you were untreated at the time of the May, 2006 resistance test, it would have been prudent to repeat the test, as your doctor did.

Your story is incomplete, so I can't judge clearly what happened and why. I would need to know whether or not the May 2006 test was a baseline test, before you ever were treated, or if it was a test conducted for the possible virolgoic failure of the regimen you were receiving. If you were on ART, it would be important to know what that regimen was, as well as any past regimens that you had received, and the clinical, immunologic, and virologic outcome. And, if you were on ART in May, 2006, did you and your doctor switch your regimen at that time? And to what drugs?

I am also unable to judge whether your doctor at that time misinterpreted the results, but that is one possibility. I say this with no intent to criticize your doctor, as ART resistance tests are complex. A resistance test is like an MRI, or a biopsy specimen, or an EKG for an HIV clinician, in that the clinician should interpret them directly, but also should seek the opinion of an expert, i.e. a radiologist, a pathologist, or a cardiologist, i.e. an expert who interprets the test on a regular basis.

In sum, great care is required in the interpretation of resistance test results, and complete information is needed to understand the resistance pattern and to determine the best course of action and next regimen, in the event that a change is warranted. Clinicians with relatively less experience should seek assistance with the interpretation of complex resistance tests.

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