PI Perspective #18

  Antiviral Potency

MODEST: In current form; less than 0.5 log drop if used alone; significant only in 3-drug combination therapy. Strongest effect when combination includes an antiviral not previously taken.

  Cell Potency

MODEST: Average less than 50 CD4+ cell increase when used alone or in combination.

  Clinical Effects

None yet reported from current trials; may require longer trials to measure benefit; similar lab marker changes in other trials have shown clinical effect, however.

  Side Effects

Very low rate; primarily nausea and diarrhea; low rate may be due to the drug’s poor absorption. Higher doses may have a different result.

  Resistance

Resistance can develop rapidly if used alone; partially cross-resistant to ritonavir and indinavir in test tubes; development of low level resistance after one year.

  Cost

HIGH: $5,700 per year wholesale, or about $16 per day.

  Antiviral Potency

VERY STRONG: Greater than 1.5 log drop when used alone, up to 2.5 log drop in 3-drug combination therapy, in some cases viral load has been reduced below detectability .

  Cell Potency

SIGNIFICANT: Average 50–100 CD4+ cell increase alone or in combination; proportional effect on CD8+ cells; results may be sustained with longer study.

  Clinical Effects

About a 50% drop in short-term mortality and progression to advanced disease; no data yet on results in early or intermediate stage disease; reports of OI and KS clearance.

  Side Effects

Moderate to high rate of nausea and diarrhea in early formulation, new formula may have reduced rate; widespread interaction with many other drugs used in treatment of HIV disease.

  Resistance

Resistance can develop rapidly if used alone; cross-resistant with indinavir (and possibly nelfinavir), partial cross-resistance to saquinavir.

  Cost

HIGHEST: $6,500 per year wholesale, or about $18 per day.

  Antiviral Potency

VERY STRONG: Greater than 2 log drop when used alone, in 2-drug, or 3-drug combination; highest percentage of users with viral load dropping below detectability .

  Cell Potency

SIGNIFICANT: Average 100 to 150 CD4+ rises alone and in combination; benefit may be sustained in longer study; no data reported on CD8+ cells.

  Clinical Effects

No clinical data in advanced, intermediate or early disease; clinical data expected soon from on-going studies.

  Side Effects

Low rate of nausea, vomiting, elevated liver functions test; very small incidence of manageable “kidney stones” in advanced patients with dehydration.

  Resistance

Resistance can develop rapidly if used alone; cross-resistant with ritonavir (and possibly nelfinavir); partial cross-resistance to saquinavir.

  Cost

LOWEST: $4,380 per year wholesale, or about $12 per day.

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