Phase I Dose Volume Escalation of Rectally Administered PC-1005 to Assess Safety, Pharmacokinetics, and Antiviral Pharmacodynamics as a Multipurpose Prevention Technology (MTN-037).

Background: On demand, topical PrEP is desired by those preferring episodic, nonsystemic PrEP. PC-1005 gel (MIV-150, zinc, and carrageenan) exhibits in vitro antiviral HIV-1, human papillomavirus (HPV), and herpes simplex virus type 2 (HSV-2) activity, attractive for a multipurpose prevention technology candidate. We evaluated the safety, pharmacokinetics, and antiviral effect of rectally applied PC-1005.

Methods: HIV-uninfected adults received a series of 3 rectal PC-1005 doses-4, 16, and 32 mL separated by 2-week washout periods. Following each dose, plasma, rectal fluid and tissue, and vaginal fluid were collected over 48 hours.

Results: Thirteen adults enrolled; 12 completed all 3 doses. All 13 adverse events reported were grade 1 or 2; 5 were judged study drug related. Plasma MIV-150 peaked 1-2 h after dosing with a median peak concentrations range of 0.07-0.23 ng/mL and median half-life range of 4.9-7.4 hours across dose volumes; median concentrations were below assay quantitation limits (BLQ) 24 hours after dosing. Rectal tissue MIV-150 peaked 0.5-1 hours after dosing at 1.4 ng/g (ng/mL) (0.8, 1.9), 46.0 (30.7, 831.0), and 79.7 (11.9, 116.0), respectively, after each dose volume; median tissue concentrations were BLQ beyond 5 hours for all doses. All vaginal fluid samples were BLQ. Ex vivo antiviral assays showed 5 hours of antiviral HPV and HSV effects but no anti-HIV activity.

Conclusions: MIV-150 rectal tissue concentrations were below the 100 ng/g target concentration and transient. Ex vivo assays demonstrated antiviral HSV and HPV effects but not against HIV. PC-1005 requires a more potent antiviral and longer-lasting formulation for further consideration as a multipurpose prevention technology candidate.

Clinical trials: NCT03408899.