Keenova eyes Xiaflex as first drug for plantar fibromatosis

Ireland's Keenova is hoping that its Xiaflex therapy can become the first approved therapy for plantar fibromatosis, a debilitating condition affecting the feet.

The drugmaker – which was known as Mallinckrodt before merging with Endo and rebranding as Keenova last year – 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. Treatment for plantar fibromatosis is orthotics, physical therapy and some off-label drug treatments, with severe and unresponsive cases requiring surgery.

There have been some off-label uses and case reports of Xiaflex for the condition, but the 436-patient EN3835-309 PFI study, also known as STRIDE, is the first prospective clinical trial to support its efficacy.

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 said was a "clinically meaningful" result.

The injectable drug also met secondary endpoints in the study 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.

It 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, causing it to curl downward like a hammer, and completed a proof-of-concept study last year with a phase 3 trial due to start in the fourth quarter of this year.

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