Maggot Therapy: How Does It Really Work?

By Ron Sherman MD, MSC, DTM&H

As far back as 1930, clinicians and researchers had a pretty good understanding of what “the right kind of maggots” could do for a wound. Those maggots are now known generically as “medicinal maggots” or “medical grade maggots.” Largely as the result of careful observations by William Baer (Chief, Orthopedic Surgery, Johns Hopkins, Baltimore) and others, we now describe the beneficial effects of medicinal maggots as being: 1) debridement; 2) disinfection; and 3) growth promotion. What is the evidence for these effects, and why is it that the only brand of medicinal maggots cleared by U.S. Food and Drug Administration (FDA) for marketing in the US (Medical Maggots™ by Monarch Labs, Irvine, CA) lists only debridement among its indications?

Let’s tackle the last issue first, because it is the easiest to address, and because it sets the stage for the rest of this discussion. The FDA grants marketing clearance or approval only if the medical claims being made can be substantiated. In other words, the company or person seeking marketing clearance must claim a benefit of the product in question for each specific condition (indication) to be treated by that product. Additionally, data must be submitted to support each claim. These days, we demonstrate medical benefits the same way that we demonstrate other scientific proofs: we test our hypotheses by conducting controlled studies. This is usually achieved by comparing the outcomes of a group of subjects receiving the investigated treatment, against the outcomes of another group of subjects who receive a mock treatment or the “conventional” treatment.

In the early years of the 20th century, however, medical practices and products were not submitted to that sort of rigorous scientific testing. Until 1990, there were no controlled clinical studies of maggot therapy at all. In the past two decades, the majority of controlled studies that have been published have primarily addressed debridement rather than the antimicrobial or growth-promoting effects.

When FDA marketing clearance was requested for the Medical Maggots™ brand of medicinal maggots, data from several controlled clinical studies was available to demonstrate debridement, but the only controlled studies demonstrating antimicrobial and growth-promoting activity were laboratory studies, not clinical trials. Therefore, marketing clearance was not requested for the indications of antimicrobial or growth-promotion activity.

Since that time, clinical data has been increasing on all fronts. Future issues of this blog will examine those studies, and more.

Sources
Baer WS. The treatment of chronic osteomyelitis with the maggot (larva of the blow fly). J Bone Joint Surg Am. 1931;13:438–475.
Sherman R. Maggot versus conservative debridement therapy for the treatment of pressure ulcers. Wound Repair Regen. 2002;10(4):208-14.
Sherman R. Maggot therapy for treating diabetic foot ulcers unresponsive to conventional therapy. Diabetes Care. 2003;26(2):446-51.
Sherman R. Age-old therapy gets new approval. Adv Skin Wound Care. 2005;18(1):12-5.
Sherman RA, Wyle F, Vulpe M. Maggot therapy for treating pressure ulcers in spinal cord injury patients.J Spinal Cord Med. 1995;18(2):71-4.

About The Author
Ron Sherman MD, MSC, DTM&H has led a long career at the forefront of biotherapy, pioneering the development of medicinal maggots for over 25 years. He is now retired from his faculty position at the University of California, but continues to volunteer as Director and Board Chair of the BTER Foundation, and as Laboratory Director of Monarch Labs.

The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, Kestrel Health Information, Inc., its affiliates, or subsidiary companies.

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