What Is Going on?
Jun 24, 2002
It seems almost daily we read about a new drug or treatment that has been found for HIV/AIDS. But where are they? I mean how soon can we expect these "wonder drugs" to reach the hands of the patients who desperately need them to survive? I refer drugs such TMC120, TMC126 and the PI TMC114. Then there are other new classes of drugs namely the Integrase Inhibitors that Merck and other pharmacutical companies are developing. There is T-20 and her cousin T-1249 they I thought were moving quickly through the process but where are they? I am not complaining the medical and pharmacutical industry has made great strides over the past several years in the treatment of HIV/AIDS tens of thousanda are alive today that might not be had it not been for gallant efforts of dedicated professionals like yourself. What is needed though is more and better meds. Onces that can be tolerated over a lifetime and that can thwart resistance. Another thing that I sense is needed is better testing. We need blood level monitoring to be standard care because its been shown that if the drugs are absorbed in the system at a substandard level resistance will be quick to develop. What about a test that more accurately measures resistance to the drugs. Perhaps one that can better measure minority mutation populations? Or test that can show which drugs are working and which are not accurately even with out stopping the medications first? Finally I have learned that in Australia physicans at Monash Unversity Medical School in Melbourne have succesfully utilized epithelium stem cells in mice to grow a new thymus. Dr Jason Gill and Dr Richard Boyd stated that could use this technique to generate a complete funtioning thymus. Regaurding their research which is published in the most recent issue of The Journel of Nature Immunology, they pointed out that you could use "gene therapy to make the whole thing resistant to HIV or even chemotherapy" This seems very exciting to me. Could you let us know what is coming out as far as new drugs and when you guestimatate them to be available to the public. Thank you again for all your wonderful work.
Response from Dr. Cohen
You have listed the research agenda for many of us for these coming years. There are new fusion inhibitors, integrase inhibitors, new generation nonnucleosides, and so on. So what's the holdup?
Well, it turns out that a few of the meds you ask about are in fact pretty close to becoming available. The reason however you can hear about promising new drugs, and then wait for years before someone can use them, is that we have in the US and Europe a multiyear process of testing meds prior to allowing them for sale. And this process occurs in stages. So let's take for an example the fusion inhibitor T20. About 4 years ago a few people were among the first to take this new fusion inhibitor as an intravenous (IV) drug. That worked, meaning their viral load did suppress about 1.5 logs. And the news was shared and it was then you might have started to hear about it as a promising new drug. But the next year was spent in trials, learing about how to use this drug given not IV but by subcutaneous self-injection, like with insulin. And that worked. And we shared the news. And it then went into studies to improve the sub-q formulation. And we now have one. But then the FDA requires the third and final step - to show what T20 adds to standard of care therapy not just for a month, but for at least 4 to 6 months. Because any new drug needs to be show it is more than a briefly active agent -- it must do something substantive that would be clinically important. And so those trials were done - Now, if it takes 6 months to enroll a trial where you need to watch everyone for 6 months, that takes a year in total. And those results, from two large trials just ended. And again, T20 worked well - adding about a log drop in viral load at week 24. So then finally these last 6 months or so are spent by the company summarizing the study data and presenting it to the FDA. And the FDA reviews it very carefully, since as you may know, there have been a few drugs approved by the FDA (for non-HIV treatment) in the past few years that were then taken off the market because of some side effect issues that became a problem noted after drug approval. So they review the data to ensure there won't be any surprises that might put people at risk. And that review takes about 6 months or so. And that's why we expect approval of T20 early next year even though we've talked about this new active drug for a few years now.
This process is the same for all the drugs you hear about at early phases. In fact, sometimes what you read of is publicity from test tube studies before a person even takes the med. Such as the TMC protease inhibitors. And so that adds another step - one in which we first need to find out what dose someone can take and tolerate and if we can find a dose someone can both tolerate and have it work against HIV. Some drugs are very active, but not well absorbed, or too toxic at doses that work. So some drugs are leads that never make it...
These steps are in place to ensure that a drug that is approved is worth taking. But in order to do these steps, there is a collaboration of researchers and people with HIV. So all of this time is spent with a few hundred, if not a thousand people having access to the medication in a research trial setting. Which is one way of providing earlier access - at least for those who are near a trial site, and eligible and willing. Which clearly is not everyone - nor a substitute for approval. But it is one reason to consider noting what is of interest to you and seeing if the research is near enough - since for example for those at our site and others like us, T20 has been very helpful for the past few years even though it is not yet an approved drug. As for a timetable for the drugs you ask about - T20 is next year, along with atazanavir, the new PI from BMS. I think that these are likely the only ones expect to be approved next year. The others are still more than a year away for all the reasons noted above...
Blood level monitoring is a similar issue, with one important difference. Yes, there are studies showing some impact of these tests. But there is also some controversy about these data, and work continues to ensure these tests are truly helpful. But unlike with meds, these tests can be available to those who can afford them - or whose insurance will cover them. At least that's the status here in the US. In Europe I understand there are clinics where drug level monitoring is already in widespread use. Here it is still undergoing testing to clarify when we need it. As for an improved resistance test, you are right that this is needed - and there are some companies working on it. Suffice it to say that it isn't easy improving these tests -if it were, we'd have switched to them by now. This is more a challenge in science, rather than a concern for restricted access prior to approval - it is just not easy to do the things needed to make the tests more sensitive.
Finally, gene therapy. The claims and potential are substantial. However you may also know again that in the US, in other treatment research for gene therapy, there was at least one death when this otherwise important approach was tried. And so there can be a profound difference in the simple press release of building a new thymus in mice, and showing it works safely in people. And that means years to test it to ensure we don't do more harm along the way.
As for claiming we can build a new thymus that doesn't allow HIV infection - again, a great goal. Perhaps achievable. But just know that we've also been hearing from gene therapy research in HIV for the past decade - and still they are at the earliest stages of testing -- as there are just so many hurdles in that type of approach, and no guarantee that we learn to jump them all along the way. However, the hurdles and failures are rarely made into a press release so it may be less clear what's not progressing, nor why. That takes more digging...
So - thanks for your interest and words of encouragement. The field of HIV research I assure you is still very active and motivated to find new drugs and new targets and better drugs. And yes there are some on the way. I think next year we will see some approvals. And more treatments in early and later phases of testing -- as proof that our field is still looking to make it better. Stay tuned...
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