The FDA granted accelerated approval on August 6, 2026, to vusolimogene oderparepvec-wtpg (RP1; Tudriqev, Replimune) in combination with nivolumab (Opdivo, Bristol Myers Squibb) for adults with unresectable advanced cutaneous melanoma who have experienced disease progression on an anti-PD-1 antibody-based regimen. The approval follows a protracted regulatory journey that included two prior complete response letters (CRLs) and a contentious advisory committee review.

Clinical Takeaway

Tudriqev plus nivolumab is now an FDA-approved option for adults with unresectable advanced cutaneous melanoma that has progressed on anti-PD-1 therapy—a setting with historically limited treatment options. Approval was based on objective response rate (ORR) and duration of response (DoR), and continued approval may be contingent upon verification of clinical benefit in a confirmatory trial.

Drug Profile & Mechanism

  • Generic name: vusolimogene oderparepvec-wtpg (RP1)
  • Brand name: Tudriqev
  • Drug class: Engineered viral immunotherapeutic (oncolytic virus)
  • Developer: Replimune
  • Combination partner: nivolumab (Opdivo, Bristol Myers Squibb), an anti-PD-1 checkpoint inhibitor
  • Mechanism: Tudriqev is a genetically modified herpes simplex virus type 1 (HSV-1) engineered to preferentially replicate within tumors, resulting in tumor lysis and release of tumor and viral antigens. It also expresses GM-CSF and a fusogenic glycoprotein (GALV-GP-R–) designed to enhance tumor killing and immune activation. In combination with nivolumab, the regimen may promote an antitumor immune response in the anti-PD-1–resistant setting.

Approved Indication & Target Population

  • Approved indication: Unresectable advanced cutaneous melanoma in adults who experienced disease progression on a prior anti-PD-1 antibody-based regimen
  • Approval basis: Accelerated approval, based on ORR and DoR; post-approval confirmatory trial(s) required to verify and describe clinical benefit
  • Regulatory context: This represents a high unmet need population; as noted by Karim Mikhail, acting director of the FDA’s Center for Biologics Evaluation and Research, patients whose melanoma has stopped responding to PD-1 blockade face a “devastating prognosis” with “far too limited” options

Supporting Study: IGNYTE Trial

  • Trial name: IGNYTE
  • Phase: Phase 1/2, single-arm, registrational
  • Enrollment: 140 adults with stage IIIB, IIIC, or IV unresectable advanced melanoma who experienced disease progression after at least 8 consecutive weeks of prior anti-PD-1–based therapy; 91 patients with at least one noninjected lesion comprised the efficacy-evaluable population
  • Regimen: Tudriqev (RP1) plus nivolumab
  • Regulatory challenges: FDA reviewers initially described the trial data as “not interpretable,” citing concerns that the response assessment methodology used in IGNYTE “confounds interpretation of the reported efficacy results” and limits the agency’s ability to verify outcomes; RECIST criteria application was a central point of contention throughout the review process

Efficacy Outcomes

  • Objective Response Rate (ORR): 24.2% (95% CI, 15.8%-34.3%) in the 91-patient efficacy-evaluable population
  • Median Duration of Response (DoR): 14.1 months (95% CI, 10.7 months-not reached)

Safety

  • Tudriqev plus nivolumab was generally well tolerated in IGNYTE, with most treatment-related adverse reactions reported as grade 1 or 2 and transient.
  • The most common nonlaboratory adverse reactions occurring in more than 10% of patients included fatigue, pyrexia, infections, chills, musculoskeletal pain, nausea, diarrhea, injection-site reactions, headache, cough, influenza-like illness, rash, vomiting, pruritus, arthralgia, constipation, decreased appetite, dizziness, dyspnea, hemorrhage, edema, and abdominal pain.
  • The prescribing information includes warnings and precautions regarding accidental exposure, herpetic infection or reactivation, injection-procedure complications, and immune-mediated events.

Regulatory History

  • First CRL (July 2025): FDA reviewers indicated they “would not recommend” approval based on results from a single-arm study
  • Second CRL (April 2026): FDA again declined approval, citing issues with the design of the IGNYTE study
  • Advisory Committee (July 30, 2026): The FDA’s Cellular, Tissue and Gene Therapies Advisory Committee (CTGTAC) voted 10–3 in favor of Tudriqev plus nivolumab; the panel acknowledged meaningful efficacy signals but raised concerns about RECIST criteria application and data interpretability; committee member Lawrence Schwartz, MD (Memorial Sloan Kettering Cancer Center) described the data as “messy” while ultimately voting yes; patient representative Diane Aronson voted no, citing the RECIST criteria as “confounding”
  • Accelerated Approval (August 6, 2026): FDA granted accelerated approval to Tudriqev plus nivolumab following the 10–3 advisory committee vote, with continued approval potentially contingent upon verification of clinical benefit in confirmatory trial(s).

Key Clinical Implications

✔ Tudriqev plus nivolumab is now an approved option for adults with unresectable advanced cutaneous melanoma who have progressed on anti-PD-1 therapy, a population with historically poor prognosis and few effective alternatives.

✔ The approval was accelerated based on ORR and DoR, not overall survival; oncologists should counsel patients that confirmatory trial data will be required to verify clinical benefit, and continued approval may be contingent on those results.

✔ The ORR of 24.2% with a median DoR of 14.1 months represents a clinically meaningful signal in an anti-PD-1–refractory population, though the single-arm trial design limits direct comparison to other regimens.

✔ The safety profile of Tudriqev appears manageable, with mostly mild-to-moderate adverse events reported in IGNYTE; however, real-world safety data in broader patient populations will be important to monitor as the drug enters clinical practice.

Bottom Line

After two complete response letters and a closely watched advisory committee vote, Tudriqev (vusolimogene oderparepvec-wtpg) plus nivolumab has secured FDA accelerated approval for adults with unresectable advanced cutaneous melanoma progressing on anti-PD-1 therapy. The drug’s journey through an unusually contentious regulatory process—marked by debates over data interpretability and RECIST methodology—underscores both the challenges of developing oncolytic viral immunotherapies and the urgent unmet need in this patient population. Oncologists should familiarize themselves with the IGNYTE trial data and monitor for results from the required confirmatory trial designed to verify clinical benefit and support continued approval.

Sources: