TONE: A Large, Prospective Post-Approval Study Investigating the Repigmentation of Stable Vitiligo Lesions Using a Point-of-Care Autologous Cell Harvesting Device

Abstract

Introduction: Vitiligo is a depigmenting autoimmune skin disorder caused by loss of melanocytes, impacting 0.5% to 2% of the global population.^1-3  For patients with stable vitiligo, surgery allows for physical transplantation of healthy melanocytes to a lesion lacking functional melanocytes.^1,4 A combination approach incorporating vitiligo surgery with pharmacotherapy may be recommended in some patients, as employing multiple modalities can improve repigmentation response.⁴ A point-of-care Autologous Cell Harvesting Device, FDA-approved for the repigmentation of stable vitiligo lesions, prepares autologous skin cell suspension (ASCS) to be applied onto laser-ablated lesions.⁵ Previously reported, the randomized, within-subject controlled pivotal trial found that 36% of ASCS-treated lesions achieved ≥80% repigmentation at 24 weeks post-treatment, versus 0% of control lesions.⁶ Here, we report on TONE, a post-approval trial using this device.

Objective: This multi-center, prospective study was conducted to evaluate repigmentation response following the application of ASCS in patients with stable vitiligo lesions in a large study population.

Methods: Enrolled patients had to have a previous unsatisfactory response to topical treatments or phototherapy, have vitiligo comprising <30% body surface area, and remain on their current use of concomitant vitiligo treatment (if applicable) for the duration of the study. A vitiligous area was identified for laser ablation and ASCS treatment, followed by at-home narrowband ultraviolet-B (NB-UVB) phototherapy. Repigmentation response at 24 weeks post-treatment was assessed by a Central Review Committee of three blinded, independent dermatologists. 

Results: A total of 107 patients were treated across 17 U.S. sites (14 in-office, 3 hospital outpatient). Enrolled patients had a mean age of 47 (SD±14.6), and half were female. Most patients had non-segmental vitiligo (n=68, 64%), while 17% (n=18) had segmental vitiligo and 20% (n=21) had focal vitiligo.​The majority (n=74, 68%) were White, followed by 14% Asian (n=16), and 4% Black or African American (n=5); 29% (n=32) of patients identified as Hispanic or Latino. Three percent (n=3) of patients were Fitzpatrick type I, with 23% (n=25) type II, 43% (n=46) type III, 20% (n=21) type IV, 9% (n=10) type V, and 2% (n=2) type VI. Fifty-two (49%) patients reported using concomitant medication(s) for their vitiligo throughout the study. At Week-24, 42% (n=42) of assessed treated areas achieved ≥80% repigmentation. No serious or severe device-related adverse events were reported.

Conclusion: These results are consistent with findings previously reported in the randomized controlled pivotal trial.⁶ This study provides further evidence confirming the safety and effectiveness of ASCS for the repigmentation of stable vitiligo lesions, as demonstrated in a large patient population. A diverse population was represented in the large patient sample with an even distribution of male and female patients, inclusion of various vitiligo sub-types, representation of all Fitzpatrick skin types I-VI, and incorporation of concomitant therapies into the protocol. This diversity among subjects is in-line with reported vitiligo patient population data,^3,4 indicating potential for generalizability of study findings in practical real-world applications.