Volume 23, Number 11 575

Changing Times

Ifirst heard of β-aminoproprionitrile fumarate (BAPN)in 1996 at the Dubai International Symposium. DrRon Genovese was there to explain the research hehad been doing on this product for several years. Also,

Dr Virginia Reef explained her studies on the product. Itlooked very promising for improving healing of ten-donitis, providing that the proper exercise regimen wasfollowed over a 6- to 12-month period.

The theory of BAPN use was rather puzzling in thatits action was to retard development of cross-linking inthe collagen fibers of the scar tissue formed during heal-ing. The reasoning of those who sought to prove thevalue of BAPN use was that by retarding collagencross-linking at the proper time of healing and applyingstress in the direction that strength is needed, the fiberswould align end to end in the direction of stress ratherthan in a random direction. Random alignment of colla-gen fibers in scar tissue occurs when little or no stress isplaced on the injured tendon. The thought was that scartissue fibers aligned in the same direction as the origi-nal collagen fibers of the tendon would provide the moststrength and would make a much stronger tendon afterhealing.

Timing of BAPN administration and near-perfectcontrol of the horse’s exercise for the long period of heal-ing were absolutely essential for the treatment to be ofvalue. Dr Genovese, a Standardbred practitioner, devel-oped a system of monitoring the progress of tendon heal-ing with ultrasound. He found that the amount and typeof exercise were determined by the amount of healing

Copyright © 2003, Elsevier Inc. All rights reserved0737-0806/03/2312-0015 $30.00/0doi:10.1016/j.jevs.2003.11.005

The Story of BAPNWilliam E. Jones, DVM, PhD

that had occurred in the tendon, as observed with ultra-sound monitoring. In his hands, BAPN treatment seemedto be of value. It appeared that horses were less likely tohave recurrent tendon injury in the healed area with theproper monitoring and exercise control. As time went by,other researchers could not show any difference in thestrength of the healed tendon between horses that hadbeen treated with BAPN and those that had not—as longas monitoring and exercise control were the same.

The drug was approved by the Food and DrugAdministration (FDA) for use in horses, and it becameavailable for general use. It was not a drug that could beused by owners or trainers. Only experienced equinepractitioners were able to use it successfully, in mostcases. Trainers, owners, and many veterinarians did notfully appreciate the importance of ultrasound monitoringand controlled exercise, nor did they appreciate how im-portant the timing of the administration was.

The drug was quite expensive, and with the limitedsuccess experienced by many veterinarians, its use felloff. For a while it was pulled off the market. A new drugcompany purchased the license for the product and triedto make a go of selling it, but they eventually took it offthe market.

What has been learned from this experience? Thereare still those who believe the drug would be useful in se-lected cases, if it were available. Others have come to theconclusion that it was really the monitoring and con-trolled exercise that were responsible for success in thosecases that did not breakdown after rehabilitation.