I assume this man has been told to reduce simple sugars as a first and necessary step to reducing his triglycerides. Given that, I think you have three options:
1. You could switch from LPV/RTV to atazanavir/ritonavir. There are data to suggest this switch will lead to a reduction in trigloycerides. There are no such data with darunavir. There could be a bit of an increased risk of virologic breakthrough with boosted atazanavir so I would watch the viral load closely - checking it 2 weeks after the switch and again 2 weeks after that. IF virus pops up you could go back to LPV/RTV or try darunavir/RTV.
2. You could drop the dose of LPV/RTV to the standard 400/100 twice a day (2 tablets twice a day). This should be fine and may well reduce his triglycerides. I favor this option.
3. Add fish oil to the fenofibrate. A dose of 4 to 6 grams a day of combined DHA and EPA (the active ingredients of fish oil) should reduce triglycerides but probably not to below 400.
Please let us know what you do and how it works.
DW