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26 March 2024

The story of Resiniferatoxin (RTX)

The story of Resiniferatoxin (RTX)

“Our M&A strategy is designed to enrich our portfolio of brands. We achieve this through early or late-stage asset R&D deals in the therapeutic area of pain.”

Quentin Le Masne de Chermont

Head of Corporate Strategy and Portfolio Management

In April 2021, Grünenthal acquired the Swiss biotech company Mestex AG. This deal gave our company the global rights to resiniferatoxin (RTX), a late-stage investigational medicine developed by Mestex AG for the intra-articular treatment of pain associated with osteoarthritis of the knee.

This condition affects more than 360 million people worldwide1. RTX has the potential to deliver long-lasting pain relief for patients thanks to its innovative mechanism that targets the Transient Receptor Potential Vanilloid 1 (TRPV1) receptors.

Since acquiring this asset, our team has achieved some exciting milestones in the development process. In March 2022, we entered an agreement to advance the global clinical Phase III programme of RTX together with NovaQuest, a firm that funds biopharmaceutical innovation. NovaQuest will reimburse Grünenthal’s investments into the clinical phase III programme of RTX, while sharing the clinical development and approval risks with Grünenthal. If RTX successfully achieves marketing approval, NovaQuest will receive some payments from Grünenthal.

Grünenthal also signed a licensing agreement giving Shionogi the exclusive rights to commercialise RTX in Japan. We confirmed this agreement in August 2022, and the contract specifies that Grünenthal will manufacture and supply RTX to Shionogi. In the same month, we enrolled the first patients in our global clinical Phase III programme for RTX. The programme investigates the efficacy and safety of intra-articular injections of RTX in adults with moderate to severe pain, associated with knee osteoarthritis who have inadequate relief from available treatment options. We are going to conduct three trials across approximately 200 sites in Europe, the US, Latin America, South Africa and Japan.

1 Cieza, A., Causey, K., Kamenov, K., Hanson, S. W., Chatterji, S., & Vos, T. (2020). Global estimates of the need for rehabilitation based on the Global Burden of Disease study 2019: a systematic analysis for the Global Burden of Disease Study 2019. The Lancet, 396(10267), 2006-2017.


Grünenthal’s resiniferatoxin receives Breakthrough Therapy Designation from U.S. FDA for pain associated with osteoarthritis of the knee

Grünenthal starts Phase III trials for resiniferatoxin in osteoarthritis-related pain (PDF)

Grünenthal to license osteoarthritis pain treatment to Shionogi in Japan in deal of up to > $ 500 million (PDF)

Grünenthal and NovaQuest enter agreement to advance the resiniferatoxin global Phase III program in osteoarthritis

Grünenthal acquires Mestex AG and its Phase-III-ready investigational medicine MTX-071 for the treatment of pain associated with osteoarthritis of the knee (PDF)

Further details on our company can be found in our annual report.



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