Medivir presented the data on their Cathepsin K Inhibitor, MIV-711, at the OARSI conference over the weekend, and the results were a bit of a mixed bag but generally positive.

Most therapies that regenerate cartilage and/or bone consist of single or multiple injections into the affected joint, and are long acting. Many of these therapies use growth factors, stem cells, and/or genetically modified cells.

MIV-711 is unique, as it is a once a day oral medication that circulates throughout the body instead of the usual targeted approach. One upside is that this drug could promote cartilage growth throughout the body. The downside, as with many medicine 2.0 approaches, is side effects.

The phase 2 study consisted of patients with moderate to severe knee osteoarthritis, of an average age of 62 years old, and an average BMI of 31 ( this is considered obese ). Psoriasis and ‘cardiovascular events’ were listed as the most notable side effects. The company notes that this may have to do with the selected population – however the placebo arm experienced significantly less side effects.

However, the results in reduction of WOMAC pain scores was large compared to the placebo group. Of note, the upwards bump in WOMAC pain scores was due to the trial design – there was a gap of approximately 1-2 weeks where the patients were not taking the medication.

The most impressive aspect of this drug is that, versus the placebo arm, the cartilage growth/loss went in the opposite direction. The strange part is that some of the benefit waned after a full year of taking the medication.

CTX-I and CTX-II ( markers of cartilage breakdown ) were greatly reduced in the group that did not receive a placebo.

MIV-711 may not be the silver bullet for osteoarthritis sufferers are looking for, but it has received FDA fast track status and may be one of the first cartilage regenerating drugs to hit the market, and despite the potential for side effects. Perhaps Medivir may see better results in the phase 3 trial.

The study is titled ‘Safety and Efficacy of Six Months´ Open Label Extension Post-RCT Using the Novel Cathepsin K Inhibitor MIV-711 in Patients with Osteoarthritis’. The powerpoint presentation can be found here. And the press release can be found here.