In the Peyronie's disease clinical studies, at 6 weeks after the first treatment cycle of XIAFLEX mg, approximately 75% of patients had antibodies against AUX-I and approximately 55% of patients had antibodies against AUX-II. Six weeks after the eighth injection (fourth treatment cycle) of XIAFLEX, >99% of XIAFLEX-treated patients developed high titers of antibodies to both AUX-I and AUX-II. Neutralizing antibodies were assayed for a subset of 70 samples selected to be representative of high and low titer binding antibody responses at week 12 of treatment. For each subject in whom a Week 12 sample was selected, the corresponding Week 6, 18, 24, and 52 samples were assayed if they were also binding antibody positive. Neutralizing antibodies to AUX-I or AUX-II, were detected in 60% and %, respectively, of patients tested.
A comprehensive review of the results of needle aponeurotomy in 1,013 fingers was performed by Gary M. Pess, MD, Rebecca Pess, DPT and Rachel Pess, PsyD and published in the Journal of Hand Surgery April 2012. Minimal followup was 3 years. Metacarpophalangeal joint (MP) contractures were corrected at an average of 99% and proximal interphalangeal joint (PIP) contractures at an average of 89% immediately post procedure. At final follow-up, 72% of the correction was maintained for MP joints and 31% for PIP joints. The difference between the final corrections for MP versus PIP joints was statistically significant. When a comparison was performed between people aged 55 years and older versus under 55 years, there was a statistically significant difference at both MP and PIP joints, with greater correction maintained in the older group. Gender differences were not statistically significant. Needle aponeurotomy provided successful correction to 5° or less contracture immediately post procedure in 98% (791) of MP joints and 67% (350) of PIP joints. There was recurrence of 20° or less over the original post-procedure corrected level in 80% (646) of MP joints and 35% (183) of PIP joints. Complications were rare except for skin tears, which occurred in % (34) of digits. This study showed that NA is a safe procedure that can be performed in an outpatient setting. The complication rate was low, but recurrences were frequent in younger people and for PIP contractures. 
The spiral cord, shown by the white arrow in Figure A, can displace the neurvascular bundle (blue arrow) and places it at risk during surgical resection. Dupuytren's contracture is a rare and progressive condition characterized by contractures of the fascia of the hand as seen in Illustration A. The fascial components involved in the disease include the pretendinous bands, spiral bands, natatory bands, lateral digital sheets, and Grayson's ligament. The offending cell is the myofibroblast which causes the normal structures to become fibrosed. Once these normal bands become pathologically involved in the disease process, they are termed cords. An easy way to remember this is that bands are normal, and cords are abnormal. The spiral cord travels dorsal to the NVB and displaces it volarly, placing it at risk during surgical resection. Example is shown in Illustrations B. Of note, Cleland's ligament is not involved in this disease process.