Trial on Efficacy and Safety of Pritelivir Tablets for Treatment of Acyclovir-resistant Mucocutaneous HSV (Herpes Simplex Virus) Infections in Immunocompromised Adults (PRIOH-1)

Randomized, open-label, multi-center, comparative trial to assess the efficacy and safety in immunocompromised subjects with acyclovir resistant mucocutaneous HSV infection, treated with pritelivir 100 mg qd (following a loading dose of 400 mg as first dose to rapidly reach steady-state plasma concentration) or foscarnet 40 mg/kg iv tid/60mg/kg iv bid.

Inclusion Criteria: 

1. Immunocompromised (due to conditions including HIV infection, hematopoietic cell or solid organ transplantation, and chronic glucocorticoid use) men and women of any ethnic group aged >16 years.

2. ACV-R mucocutaneous HSV infection based on clinical failure requiring switch to foscarnet treatment or positive genotypic/phenotypic ACV resistance testing for current lesion. Clinical failure is defined as no improvement after at least 7 days with local agency approved high doses with acyclovir, valacyclovir or famciclovir.

3. Lesions accessible for visual inspection to allow assessment of lesion healing including visualization by endoscopy or pharyngoscopy. 4. Willingness to abstain from the application of lotions and/or creams to the area with HSV lesions. Wet/dry saline dressings or bandages at lesion site are allowed.

5. Willing to use highly effective birth control: Male subjects must be surgically sterile (eg, vasectomy at least for the 26 weeks before starting treatment) or must agree to use an adequate method of contraception (see definition below) during sexual intercourse with women of childbearing potential to make sure the fathering of a child will be ruled out during treatment and for at least 1 complete month after the final dose of trial medication. Female subjects of non-childbearing potential must be either surgically sterile (hysterectomy, bilateral tubal ligation, salpingectomy, and/or bilateral oophorectomy at least 26 weeks before starting treatment) or postmenopausal (defined as spontaneous amenorrhea for at least 2 years, with follicle-stimulating hormone (FSH) in the postmenopausal range at start of treatment based on the laboratory’s ranges). Female subjects of childbearing potential must use an adequate method of contraception (see definition below). An adequate method of contraception is defined as a highly effective method of contraception plus use of a condom during participation in this trial and for at least 1 complete month after the final dose of trial medication. A highly effective method of contraception is defined as: o copper intrauterine device, o the levonorgestrel-releasing intrauterine system, o the progestogen implant, o combined (estrogen and progestogen containing) hormonal contraception (oral, intravaginal, transdermal) associated with inhibition of ovulation, o progestogen-only hormonal contraception (oral, injectable, implantable) associated with inhibition of ovulation.

6. Subject, and/or their legally authorized representative, must be willing and able (in the opinion of the Investigator) to understand the Informed Consent Form.

7. Negative serum β-HCG (beta-human chorionic gonadotropin) test for women of child[1]bearing potential at Screening and a negative urine pregnancy test at Day 1.

8. Subject must give written informed consent. For subjects, who are unable to provide informed consent for whatever reason, written consent must be obtained from the legal representative

Exclusion Criteria: 

1. Known resistance/intolerance to pritelivir and/or foscarnet or any of the excipients.

2. Previous treatment in PRIOH-1

3. Need to use warfarin, phenytoin, paclitaxel.

4. Baseline safety laboratory abnormalities: o ANC 5 x ULN o bilirubin >2.5 x ULN

5. History or current evidence of gastrointestinal malabsorption which, in the opinion of the Investigator, may affect the extent of absorption of pritelivir.

6. Severe renal insufficiency (eGFR ≤29).

7. History or current evidence of significant cardiovascular, pulmonary, hepatic, renal, gastrointestinal, hematological, endocrinological, metabolic, neurological, psychiatric, or other diseases, which, in the opinion of the Investigator, may affect the subject’s safety or interfere with the trial.

8. Abnormalities in hematological, clinical chemical or any other laboratory variables at Screening measured by the central or local laboratory regarded as clinically relevant by the Investigator unless they are due to underlying disease or condition.

9. Not able to communicate meaningfully with the Investigator and site staff.

10. Any other condition which in the opinion of the Investigator would interfere with successful completion of this clinical trial.

11. Any other local condition including bacterial superinfection which in the opinion of the Investigator would interfere with the efficacy evaluation.

12. Pregnant and/or breastfeeding women.

13. Having received an investigational drug in an investigational drug trial within 7 half-lives after the last administration of this drug before initiating trial medication. Current participation in a clinical trial without receiving other investigational drugs (eg, follow-up phase of a trial, observational study) is permitted.