# RP1 Combination Wins Accelerated Melanoma Approval

> The FDA authorized Tudriqev with nivolumab after anti-PD-1 progression, but the decision rests on tumor response and requires confirmatory evidence of clinical benefit.

_Source: FDA accelerated-approval notice, Replimune announcement, and independent oncology reporting · 2026-08-07 · 8 min read · Verified against primary sources_

Canonical: https://iyu.app/e/rp1-nivolumab-melanoma-accelerated-approval

## The 60-second version

The FDA granted accelerated approval to Tudriqev plus nivolumab for adults with unresectable or metastatic cutaneous melanoma after anti-PD-1 progression.

**Key points**

- The decision was based on objective response rate and duration of response in a 140-patient single-arm IGNYTE cohort.
- Independent review found confirmed responses in about one-third of patients, with a reported median response duration beyond 35 months.
- The study cannot by itself prove a comparative survival benefit or fully isolate RP1's contribution from nivolumab.
- Replimune must verify clinical benefit in post-approval trial work, and continued approval may depend on the outcome.

**Verdict.** This is a meaningful new option in a difficult treatment setting, but its accelerated status and confirmatory obligation are part of the result, not a footnote.

## Full explainer

> **⚑ Caveat:** This is an **accelerated approval**, not conventional approval based on a randomized survival benefit. Replimune must verify clinical benefit in post-approval trial work, and continued approval may depend on the result.


### Decision — What the FDA authorized

On August 6, 2026 in the United States, the FDA granted accelerated approval to **vusolimogene oderparepvec-wtpg**, marketed as **Tudriqev** and developed as RP1, in combination with nivolumab. The date was August 7 in Beijing.

The indication is limited to adults with **unresectable or metastatic cutaneous melanoma** whose disease progressed on a prior anti-PD-1-based regimen. It is an approval of the combination in this post-PD-1 setting, not RP1 monotherapy and not a first-line authorization for melanoma generally.

- **Product:** Tudriqev, formerly RP1, plus nivolumab.
- **Population:** Adults with unresectable or metastatic cutaneous melanoma after progression on an anti-PD-1-based regimen.
- **US decision date:** August 6, 2026; August 7 in Beijing.
- **Regulatory route:** Accelerated approval based on response rate and duration of response.
- **What follows:** Post-approval trial work must verify clinical benefit.


### Mechanism — A local injection paired with systemic immunotherapy

RP1 is an oncolytic immunotherapy administered by injection into tumors. It is designed to disrupt infected tumor cells and increase immune recognition of tumor material. Nivolumab blocks PD-1, removing one brake on T-cell activity.

The proposed logic is complementary: use the injected tumor as a site of immune activation while nivolumab supports a broader systemic response. Responses observed in non-injected lesions are consistent with that hypothesis, but biological consistency is not a substitute for controlled evidence of clinical benefit.


### Evidence — What the IGNYTE study showed

The registrational evidence came from the phase 1/2 IGNYTE study. Its relevant cohort included **140 patients** with advanced melanoma and confirmed progression on an anti-PD-1-based regimen who received intratumoral RP1 with intravenous nivolumab.

- **140** — patients in the registrational post-PD-1 cohort
- **33.6%** — confirmed response by independent review using modified RECIST
- **32.9%** — confirmed response using standard RECIST
- **>35 mo** — reported median duration of response

An objective response rate near one-third means that predefined tumor shrinkage was confirmed in roughly one of every three study participants. Duration of response asks a different question: among responders, how long did the response persist? Both were central to the accelerated approval decision.

> A durable response signal can support accelerated approval; it does not by itself prove that a treatment extends survival compared with another therapy.


### Limits — What the study cannot establish

IGNYTE was a **single-arm** study. Without a randomized comparator, it cannot directly measure the combination's advantage over another treatment, establish a causal overall-survival benefit, or fully isolate RP1's contribution from nivolumab.

- Response rate is a tumor-measurement endpoint, not the same as living longer or feeling better.
- Cross-study comparisons can mislead because eligibility, disease burden, prior treatment and follow-up differ.
- Results from a selected trial population may not reproduce exactly in broader clinical use.
- The approved label and safety information, rather than a news summary, govern clinical use.

> **i** The evidence described here applies at the study and regulatory level. Treatment decisions require patient-specific assessment by qualified oncology professionals; this article does not provide personal medical advice.


### Obligation — Why confirmatory evidence is decisive

Accelerated approval allows earlier access when an endpoint is considered reasonably likely to predict clinical benefit. The tradeoff is a binding evidence obligation after approval. The sponsor must complete trial work that verifies benefit, and the FDA may reconsider the indication if the evidence does not confirm it.

The next facts to watch are the confirmatory trial's comparator, endpoints, enrollment progress, completion date and public results. Those details will determine whether the initial response signal becomes robust evidence of clinical benefit.

> **→** The accurate takeaway: the combination is now an authorized US option for a defined post-PD-1 population, while its longer-term regulatory standing still depends on confirmatory evidence.


## Primary sources

- [FDA — accelerated approval notice (August 6, 2026)](https://www.fda.gov/drugs/resources-information-approved-drugs/fda-grants-accelerated-approval-vusolimogene-oderparepvec-wtpg-combination-nivolumab-melanoma)
- [Drugs@FDA — official approved-drug database](https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm)
- [Replimune — FDA accelerated approval announcement (August 6, 2026)](https://www.replimune.com/)
- [CancerNetwork — independent oncology report (August 6, 2026)](https://www.cancernetwork.com/view/fda-approves-rp1-nivolumab-for-progression-on-anti-pd-1-therapy-in-melanoma)
- [The Pharma Letter — independent industry report (August 7, 2026)](https://www.thepharmaletter.com/pharmaceutical/fda-reverses-course-with-accelerated-nod-for-tudriqev-in-melanoma)

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