Background L provided a 19.4 month (mo) median PFS in the phase 3 Study of Lenvatinib in Differentiated Cancer of the Thyroid (SELECT) and an objective response rate of 60.2%; however, all patients (pts) experienced some toxicity. In Canada, a PSP was created to offer L to pts with rDTC prior to public funding. We report the prescription practices and treatment patterns of these pts. Methods Between August 2015 and January 2019, 223 pts with rDTC started L as part of the PSP. Prescriber information, patient demographics, start and discontinuation dates, starting doses and dose modifications and reasons for discontinuation were ascertained whenever possible. Pt and prescriber demographic and clinical characteristics were described using statistics. Kaplan-Meyer method was used to estimate persistency on L, defined as time from first prescription to discontinuation. Results Two-hundred twenty-three rDTC pts were analyzed (42% female, mean age 63.4 years). Median study follow-up was 15.8mo. Mean starting dose was 21.2mg and was 24mg for 158 pts (66%), 20mg for 35 pts (15%) and lower for 47 pts. Median KM estimate of persistency on L was 15.8mo and was similar for pts starting full or reduced dose. Treatment persistency was similar between all provinces but there was a trend favouring prescribers with more than one patient in the PSP versus those with only one patient (18.0mo vs 10.2mo, p=0.0922) and for pts treated by endocrinologists compared to other specialties. There was also a trend for longer persistency in pts who had dose modifications compared to pts treated with constant doses (19.0mo vs 9.8mo, p=0.0577). One hundred and twelve pts have discontinued L (39 deaths from disease, 23 progressive disease/palliation, 15 for medical reasons other than toxicity (including decision to pursue alternative therapy), 14 from toxicity and 21 undisclosed/other reasons). Conclusions To date, this is the largest presented real-world analysis of the treatment patterns of L in pts with rDTC and our estimates of treatment duration as proxy for effectiveness are comparable to the phase 3 SELECT trial. Toxicity led to a minor proportion of discontinuations. Legal entity responsible for the study The authors. Funding Eisai Supported the Patient Support Program, hosted by Innomar Strategies, Inc. Disclosure S.J. Hotte: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Eisai. E. Winquist: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Eisai. N. Chua: Honoraria (self), Advisory / Consultancy: Eisai. J..D. Ruether: Honoraria (self), Advisory / Consultancy: Eisai. N. Lamond: Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Eisai. S. Ezzat: Advisory / Consultancy: Eisai. M. Massicotte: Honoraria (self), Advisory / Consultancy: Eisai. R. Wong: Advisory / Consultancy: Eisai. P. Lam: Full / Part-time employment: Eisai. B. Yap: Full / Part-time employment: Eisai. M.K. Krzyzanowska: Honoraria (self), Research grant / Funding (institution): Eisai; Research grant / Funding (institution): Exilixis. All other authors have declared no conflicts of interest.