New U.S. Clinical Trial of Neridronate

In the last fifteen years, only two randomized, placebo-controlled trials for CRPS have been conducted in the United States. Sadly, both were unsuccessful.

Our optimism is rising, however, with the U.S. Food and Drug Administration’s declaration in 2014 that Complex Regional Pain Syndrome (CRPS), also known as Reflex Sympathetic Dystrophy (RSD), is officially a rare disease. The designation is a strong catalyst for new drug development. Developers qualify for clinical trial tax incentives, may sell the drug without competition for seven years, and may enroll fewer patients in a trial (as recruiting is more difficult in small populations).

Four pharmaceutical companies are now considering clinical trials for CRPS in the United States.

The first out of the gates is Grunenthal, a Germany-based, family-owned company. The trial medication is neridronate, an amino-bisphosphonate. Attention mounted for neridronate after a startlingly successful small trial in Italy, which was was published in the journal Rheumatology at the turn of 2013. The Italian trial’s inclusion criteria were strict; individuals whose CRPS onset was greater than four months were excluded. The American trial inclusion criteria are not as strict, with the exception that individuals with CRPS Type 2 are excluded. (The diagnosis of CRPS Type 2 is made when specific nerve damage can be detected, whereas for Type 1 such damage is not evident.

Grunenthals’ recruitment for the neridronate trial started in early April 2015.

The bisphosphonate class of drugs has been used overseas to treat CRPS for years. Querying PubMed for bisphosphonates for CPRS will reveal a small trove of published research (more than 20 papers) dating back to 2002. (PubMed is a great website to bookmark to search the latest scientific research. Again, this search engine indexes published research, which may not prove fully accurate after deeper scientific investigation.)

Currently, two other pharmaceutical corporations are submitting plans to the FDA for clinical trials that will evaluate therapies for a CRPS indication. It’s an exciting time for all individuals affected by CRPS. Stay tuned!

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