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Using RP1 to treat advanced skin cancers in organ transplant patients

An Open-Label, Multicenter, Phase 1B/2 Study of RP1 in Solid Organ and Hematopoietic Cell Transplant Recipients With Advanced Cutaneous Malignancies

PHASE1; PHASE2 · Replimune Inc. · NCT04349436

This study is testing a new treatment called RP1, which uses a modified virus to see if it can help organ transplant patients with advanced skin cancer that hasn’t responded to other treatments.

Quick facts

PhasePHASE1; PHASE2
Study typeInterventional
Enrollment65 (estimated)
Ages18 Years and up
SexAll
SponsorReplimune Inc. (industry)
Drugs / interventionsradiation
Locations23 sites (Phoenix, Arizona and 22 other locations)
Trial IDNCT04349436 on ClinicalTrials.gov

What this trial studies

This Phase 1B/2 study is a multicenter, open-label trial investigating the safety and effectiveness of RP1, a genetically modified herpes simplex virus, in treating advanced cutaneous malignancies in organ transplant recipients. The study aims to evaluate the objective response rate and tolerability of RP1 through intra-tumoral injections in patients with confirmed recurrent or metastatic skin cancers. A total of 65 patients will be enrolled, participating for up to three years, which includes a screening period, treatment phase, and follow-up. The trial specifically targets patients who have not responded to previous treatments and have stable organ transplants.

Who should consider this trial

Good fit: Ideal candidates include organ transplant recipients with advanced cutaneous malignancies who have not responded to prior treatments.

Not a fit: Patients with stable organ transplants who do not have advanced or metastatic cutaneous malignancies may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new therapeutic option for organ transplant patients suffering from advanced skin cancers.

How similar studies have performed: While the use of oncolytic viruses is an emerging field, this specific approach in organ transplant patients is novel and has not been extensively tested in prior studies.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion Criteria:

1. Voluntary agreement to provide written informed consent prior to any study procedures and the willingness and ability to comply with all aspects of the protocol and understand the risk to their organ allograft.
2. Patients with histologically or cytologically confirmed recurrent, locally advanced or metastatic (to skin, soft tissue or lymph nodes) cutaneous malignancies, including CSCC, basal cell carcinoma, Merkel cell carcinoma, and melanoma
3. Patients must have progressed following local resection, prior radiation, topical or systemic therapies.
4. Documentation from the patient's transplant physician confirming that the patient's allograft is stable.
5. Patients for whom surgical or radiation treatment of lesions is contraindicated.
6. At least 1 lesion that is measurable and injectable by study criteria (tumor of ≥1cm in longest diameter or ≥1.5 cm in shortest diameter for lymph nodes).
7. Eastern Cooperative Oncology Group (ECOG) performance status ≤1.
8. Anticipated life expectancy \> 6 months
9. Baseline ECG without evidence of acute ischemia.
10. All patients must consent to provide archived or newly obtained tumor material (either formalin-fixed, paraffin-embedded \[FFPE\] block or 20 unstained slides).

Key Exclusion Criteria:

1. Prior treatment with an oncolytic therapy.
2. Patients with visceral metastases.
3. Patients with active herpetic infections or prior complications of HSV-1 infection (e.g., herpetic keratitis or encephalitis).
4. Patients with a history of organ graft rejection within 12 months.
5. Had systemic infection requiring intravenous (IV) antibiotics or anti-virals, or other serious infection within 60 days prior to dosing.
6. Patients who require intermittent or chronic use of systemic (oral or intravenous) anti-virals with known anti-herpetic activity (e.g., acyclovir) unless for organ allograft preservation.
7. Patients requiring CTLA-4-Ig medications.
8. Ongoing or recent (within 5 years) evidence of significant autoimmune disease that required treatment with systemic immunosuppressive treatments beyond that required for maintenance allograft rejection prevention. The following are not exclusionary: vitiligo, childhood asthma that has resolved, type 1 diabetes, residual hypothyroidism that requires only hormone replacement, or psoriasis that does not require systemic treatment.
9. Active infection with hepatitis B virus (HBV), hepatitis C virus (HCV) or human immunodeficiency virus (HIV).
10. Any history of transplant-related viral infections, such as BKV, EBV or CMV, within 3 months of study entry. Patients with a history of hepatitis B or C virus must have undetectable viral load within 3 months of study entry.
11. Patients with a condition requiring an increase in the patient's usual immunosuppressive medications within 60 days of study treatment.
12. Known active CNS metastases and/or carcinomatous meningitis.

Where this trial is running

Phoenix, Arizona and 22 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Cutaneous Squamous Cell Carcinoma, Merkel Cell Carcinoma, Basal Cell Carcinoma, Melanoma

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.