Juvenile rheumatoid arthritis (JRA) is a disease that results in chronic joint inflammation, and is the most common rheumatology disease in children.
The American College of Rheumatology classifies juvenile RA into 3 subtypes, one of which is systemic JRA. The news that the FDA just approved tocilizumab (Actemra®) from Roche for pediatric systemic JRA (SJRA) is therefore good news for several reasons:
1. Very few drug companies obtain pediatric indications for their drug since registration trials are more routinely undertaken with adult patients.
2. In several adult phase III clinical trials, tocilizumab was also shown to delay joint damage as measured by ACR20, ACR50 and ACR70 responses. An ACR 20 response requires a patient to have a 20% reduction in the number of swollen and tender joints.
If you look at the adult phase III clinical data that has been published for the AMBITION, LITHE, OPTION, TOWARD, RADIATE studies, what is noticeable to me is the high percentage of patients across the studies who had an ACR20 response within 24 weeks (70%, 56%, 59%, 61%, 50%); in all cases a significant improvement over placebo plus methatraxate or other disease modifying anti-arthritic drug (DMARD).
Source: Roche data on adult phase III trial results
However, it’s clear from the above data that fewer patients had deep responses e.g. ACR50, ACR70. Tocilizumab is a treatment option for those who have failed previous RA therapies, and while not a cure, can provide symptom relief and improve joint function in those suffering from moderate to severe RA.
According to the Roche press release, data from the pediatric study known as TENDER, showed that 64/75 children (85%) of children with SJRA experienced an ACR30 improvement. Given the fact the drug is already approved for adult use, and has extensive phase III trial data, a small pediatric sample size is not unexpected.
A pediatric approval is good news, as all too often pharma and biotech companies neglect this market. I plan to write more in future posts about RA drugs in development as I think this is a market that may continue to evolve new treatment options over the next few years.