INCB009471

INCB009471, an investigational CCR5 antagonist, appears to be potent and well tolerated, according to results of a small phase IIa study presented in 2007.¹

The drug is being developed by US biotech company Incyte and is the first of two CCR5 antagonists under development by the company. Test-tube studies have demonstrated that INC9471 has potent activity against several clades of HIV-1 and against virus that is resistant to the four established classes of antiretrovirals. Phase I studies have shown the drug to be rapidly absorbed, with a long half-life of around 60 hours.

In a randomised, dose-ranging, two-week trial, 19 participants received INCB9471 monotherapy (200mg once daily) and four received placebo. Trial participants were either treatment-naive or ARV-experienced but off therapy for at least three months. At baseline, the cohort’s mean CD4 cell count was 565 cells/mm³ and mean viral load was 4.7 log₁₀ copies/ml. Five individuals, all of whom took active drug, had viral loads above 100,000 copies/ml. At day 20, six days after the last dose, there was a mean viral load reduction of nearly two logs. At two weeks after the last dose of INCB9471, mean viral load decline was still nearly one log.

Overall, INCB9471 appeared to be safe and well-tolerated with no serious adverse events or therapy discontinuations. A 200mg once-daily dose was due to be studied in phase IIb trials but Incyte has released no further information on the product since 2007.