Keenova's Xiaflex Meets Phase 3 Goals in Plantar Fibromatosis, Filing Planned Before Year-End

Keenova is hoping that its Xiaflex therapy can become the first approved therapy for plantar fibromatosis, a debilitating condition affecting the feet. The drugmaker said that Xiaflex (collagenase clostridium histolyticum) met its objectives in a phase 3 trial in plantar fibromatosis patients and will be filed for approval in the new indication before the end of the year.

Plantar fibromatosis, also known as Ledderhose disease, leads to the formation of small, hard, and non-cancerous growths along the plantar fascia, thick connective tissue that supports the arch of the foot. These growths can be painful, making it difficult for patients to walk, and in rare cases, can lead to the toes curling down into an awkward position that can severely restrict mobility. There is no cure for plantar fibromatosis. Current treatment options include custom insoles (orthotics), topical treatments, over-the-counter pain and anti-inflammatory medications, radiation therapy and steroid injections, and ultimately, surgery may be required to remove the nodules.

The 436-patient EN3835-309 PFI study, also known as STRIDE, is the first prospective clinical trial to support the efficacy of Xiaflex for this condition. It met its primary endpoint, with a statistically significant improvement in pain with Xiaflex versus placebo, as measured by the Average Daily Pain Intensity on the Numeric Rating Scale (NRS), which Keenova described as a "clinically meaningful" result. The injectable drug also met secondary endpoints related to difficulty and activity limitation as measured by the Foot Function Index (FFI) scale, FFI pain subscale, global assessments of improvement and disease severity, and nodule characteristics.

A separate peer-reviewed manuscript published in The Journal of Foot and Ankle Surgery reported real-world treatment patterns for plantar fibromatosis and highlighted persistent symptoms after conservative care. The findings showed that most patients receive treatments such as injectable corticosteroids, oral corticosteroids, and physical/occupational therapy. Although surgery is infrequent, conservative treatments often continue after surgery, which may suggest disease recurrence or persistent symptoms. The manuscript noted no FDA-approved nonsurgical options and called for more research on long-term outcomes and effective therapies.

Xiaflex is already approved to treat Dupuytren's contracture and Peyronie's disease and brought in sales of $546 million for Keenova last year, accounting for more than a third of the company's total turnover. Approval in plantar fibromatosis would add around 300,000 people a year to the potential population targeted by the drug. Xiaflex is also being developed for hammer toe, a common foot deformity where the toe bends abnormally at the middle joint, and completed a proof-of-concept study last year with a phase 3 trial due to start in the fourth quarter of this year.

Keenova — which was known as Mallinckrodt before merging with Endo and rebranding as Keenova last year — is headquartered in Dublin, Ireland.