DTG + 3TC bitherapy
Jun 12, 2016
Dear Doc. A biiiig thanks for your time and advice. I recently read about the bi-therapy approach with DTG+3TC (basically the Triumeq without ABC) and it seems promising, hopefully I can participate and start now in July in Spain). How long does this approval usually take, since both drugs are already approuved and in use? Or most likely (if this approach confirmed), this two-drug regimen will also take years to reach the patients? For example 2020-ish, when hopefully the injectable LA treatement comes out? Thanks for your time.
Response from Dr. Young
Hello and thanks for posting.
Yes, the dual therapy regimen of lamivudine (3TC. Epivir) + the integrase inhibitor dolutegravir (DTG, Tivicay) has gotten quite a bit of recent attention since the presentation of the pilot PADDLE study. In this study, 20 treatment naive individuals began treatment with this two, rather than the conventional three drugs recommended for initial treatment.
The theoretical basis for the study is the observation that DTG is very potent, and HIV appears to have difficulty in developing resistance to the drug. A two drug regimen, especially one with the already generic, and very well tolerated 3TC should be less expensive than a three drug treatment. Moreover, the idea of avoiding both tenofovir (with incumbent risks of bone and kidney toxicity) and abacavir (with the need for genetic screening to avoid allergy, and possible risk of raising cardiovascular disease rates) is attractive.
The results of the small study were encouraging, with rapid viral load decline- indeed similar in rates to those seen in other three drug studies of DTG with 3TC and abacavir.
Two drug therapy has also shown promising results for maintenance therapy for patients already virologically suppressed in the phase 2 LATTE-2 study of injectable, long-acting ripivirine and the experimental integrase inhibitor cabotegravir. This regimen should be able to be dosed every month or every other month, avoiding the issues of daily pills and probably improving treatment adherence. A phase 3 (FDA registrational study) of this regimen is starting soon, and likewise, will take upwards of 2-3 years to see the final analysis (i.e, 2019-2020 timelines).
You ask when the treatment will reach patients. There is soon to be a fully powered (ie sized) study that compares this two to the usual three drug Triumeq (DTG containing) regimen. It will likely take upwards of 1.5 to 2 years to see the results of the study. But both 3TC and DTG are already FDA approved, so the issue isn't going to be FDA approval, per se, but rather when there is sufficient data to support using the regimen- and the endorsement of the smart men and women on US and international guideline committees. I do not recommend (in general) that patients or care providers venture too far of the very well proven ranch of the evidence-based treatment guidelines.
So stay tuned. The next years should prove to be very interesting from the drug discovery and treatment strategy perspective.
Be well, BY
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