1255P - Impact of intralesional interleukin 2 (IL2) for in-transit melanoma in two Canadian centres

Abstract

Background: In-transit (IT) melanoma is a form of metastatic disease that is associated with high morbidity and is often refractory to treatment. Intralesional (IAL) IL2 has been increasingly utilized to obtain loco-regional control. This study utilizes a national registry to evaluate response and duration of response of standardized IAL therapy at tertiary centres in 2 provinces. Methods: Patients (pts) receiving IAL IL2 between 2000 and 2017 were included. Data regarding patient demographics, stage, extent of disease, and all treatments were collected. All pts received a median IL2 dose of 12 million IU given as an IAL injection every 2 to 4 weeks repeated 2 to 8 times to complete a session. Results: A total of 87 pts aged 21 to 94 (mean: 69 yrs) were included. IT disease was located in the following areas: limbs in 68 pts (79%), head and neck in 13 pts (15%) and trunk in 5 pts (6%). 20% of pts developed IT within 3 months of primary diagnosis, 69% developed IT after 6 months and 11% after 3 years. IT lesions per individual ranged from 1 to 40+; 45% had >10 lesions. Patients had a complete response rate of 32% (28 pts) and a partial response rate of 38% (33 pts). 27 (31%) pts experienced a recurrence after their 1st IL2 session, with a mean of 225 days (median: 204). Of these pts, 15 (56%) pts developed loco-regional recurrences, while 6 (22%) developed distant metastases and 6 (22%) had both distant and loco-regional recurrences. 27 pts (31%) received systemic treatment for metastatic disease. 18 (21%) pts died of disease, while 3% died of other causes while disease was present. 7 (8%) died of other causes with disease status unknown, and 25 (29%) and 34 (39%) are recorded alive with more than a year (1 to 11 yrs) or less than a year follow up, respectively. No grade 3 or 4 toxicity was experienced by pts who received IL2 therapy. On multi-variant analysis, age, extent of disease and prior systemic therapy did not impact overall response (X2 test, p > 0.05). Conclusions: IAL IL2 appears to be an effective therapeutic option for pts with advanced melanoma and IT disease, with an overall response rate of 70%. With further long-term follow up of these pts, the impact on overall survival can be determined. Legal entity responsible for the study: Global Melanoma Research Network. Funding: Global Melanoma Research Network. Disclosure: All authors have declared no conflicts of interest.