TONE: A Large, Prospective Post-Approval Study Investigating the Repigmentation of Stable Vitiligo Lesions Using a Point-of-Care Autologous Cell Harvesting Device
Authors: Pandya Amit G. 
Published: November 2024

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.