The annual conference of the American Academy for Dermatology is the place to go whenever you want to engage in meaningful dialogue with researchers and clinicians at the top of their game. The 2019 Conference (March 1-5) in Washington DC was no exception. From a vitiligo perspective, the conference gave a glimpse into how novel therapies are evolving.
The approach to the treatment of vitiligo follows a proven pattern. Effective management of the disease requires:
1. arresting the spread of depigmentation, 2. promoting repigmentation in vitiligo lesions, and 3. the prevention of relapse.
To be successful, any treatment must address all three of these focal areas. These three approaches are central for both present and future attempts to permanently restore pigmentation to vitiligo affected skin.
Common treatments today The most popular approach to the treatment of vitiligo today combines steroids or calcineurin inhibitors to suppress the autoimmune component of the disease, with light therapy (typically UVB or laser) to promote the growth of melanocytes. To be effective, phototherapies tend to require 2-3 sessions per week over a prolonged period of time (often a year). Patients often find the commute to treatment centers to be highly time consuming and hard to justify. Relapses are common when realities of life create disruptions in the program. While home-located light treatment platforms require space, they tend to provide much greater flexibility, patient satisfaction, and even reduced out of pocket costs.
While steroids or calcineurin inhibitors may be used to arrest advanced disease, large lesions may prove difficult to depigment. In order to understand why, we need to see how melanocytes grow back into the repigmented areas. Repigmentation is dependent on available reserves and can take place either by the activation of stem cells in the center of the lesion or by the perimeter closing in on the depigmented area. The latter is limited by the fact that the growth seldom exceeds 10 mm. Repigmentation from the center tends to start from stem cells typically residing in hair follicles. These islands of pigmentation start out resembling freckles that often grow together, resulting in continuous depigmentation over time.
Whenever stem cells are depleted as a result of long-term vitiligo, transplants have proven to be an effective source to bring pigment cells to the center of large lesions. These transplants may be as small as 1mm in diameter, and they are transplanted equidistant from one another to form reservoirs from which melanocytes can spread to ultimately form a uniform layer. The spread of melanocytes is typically boosted with intensive light treatment.
Some treatments under development
In 2019 we see a strong focus on the development of complementary methodologies for the treatment of Vitiligo. TeVido Bio Devices is a recently funded startup that prepares cell extracts of a patient’s own skin to be transplanted to repigment vitiligo lesions. The methodology is minimally invasive and can cover 10 times the area of the original tissue. TeVido Bio Devices will offer its services to dermatologists in May 2019.
The laboratory of Dr. John Harris at the University of Massachusetts is working on using JAK inhibitors to shield melanocytes from being taken out by T cells. The methodology is very promising as JAK inhibitors already hold FDA approval for other applications. JAK inhibitors are in Phase II clinical studies and may be accepting patients to phase 3 clinical trials within a foreseeable future.
The laboratory of Professor Caroline Le Poole at Northwestern University, Chicago has developed a methodology based on a modified version of the heat shock protein HSP70i. By injecting DNA coding for the modified protein, the plasmid has been able to reverse vitiligo in both mice and swine. This well-published therapy is being developed towards clinical trials by Temprian Therapeutics Inc.
The fact that Vitiligo relapses in the same place time after time has led researchers to understand that the skin must hold a memory of past attacks. This hypothesis has led Prof. John Harris to investigate resident memory T Cells that stay embedded in vitiligo lesions. The resident memory T cells are subject to research that may very well hold future therapeutic value.
The beauty of the therapies under development is that they all support one another. When successful, these treatments would provide patients and clinicians with an effective tool kit to stop the progression, to stimulate the repigmentation, and to prevent relapse.
Disclaimer: The information on this blog is intended for orientation purposes only. For medical treatment options please consult your dermatologist.