4598 Retraction The abstract by Yang et al entitled, “Cost effectiveness analysis of nadofaragene firadenovec for the treatment of high-risk, bacillus Calmette-Guerin–unresponsive, non-muscle invasive bladder cancer from a US third-party payer perspective,” ( Journal of Clinical Oncology 42, no. 16_suppl 4598; DOI 10.1200/JCO.2024.42.16_suppl.4598) published on May 29, 2024, has been retracted. The authors wish to retract this article as it is undergoing additional review and further updates are expected. They could not rule out that the current results may be incorrect, inaccurate, or misleading. It is important to provide the best estimate of nadofaragene’s cost effectiveness vs pembrolizumab in this space for healthcare decision making whereas uncertainty remains at this time. The authors are no longer able to endorse the work. This abstract was retracted on August 26, 2024. Background: Bladder cancer is the second most common cancer in the urinary tract in the United States (US), with 75% restricted to the superficial layers of the bladder and termed as non-muscle invasive bladder cancer (NMIBC). Bacillus Calmette-Guerin (BCG) is the standard of care for high risk NMIBC patients; however, bladder preserving treatments are limited after BCG failure. Nadofaragene firadenovec, an interferon-alfa-2b encoding gene therapy, is approved for the treatment of high-risk BCG-unresponsive NMIBC with carcinoma in situ (CIS) with or without papillary tumors (CIS ± Ta/T1). This study assessed cost-effectiveness of nadofaragene firadenovec compared to pembrolizumab from a US third-party payer perspective. Methods: A Markov model was developed to estimate total costs, quality-adjusted life-years (QALYs), and corresponding incremental cost per QALY ratios (ICER) over a lifetime time horizon for patients treated with nadofaragene firadenovec or pembrolizumab. In the absence of head-to-head data comparing nadofaragene firadenovec to pembrolizumab, the model population was based on Phase 3 trial for nadofaragene firadenovec (NCT02773849, data cut: July 8, 2019) and included adult patients (mean age of 71.0 years; 11.7% female) with high-risk, BCG unresponsive NMIBC with CIS ± Ta/T1. Pembrolizumab data was informed by the published KeyNote-057 trial (NCT02625961, data-cut: May 25, 2020). The model consisted of 7 mutually exclusive health states with a three-month model cycle: NMIBC disease-free, NMIBC recurrence, MIBC, metastatic disease, cystectomy, post-cystectomy, and death. Drug costs, adverse events (AEs) costs, and health state associated medical costs were included and discounted at 3% annually. The nadofaragene firadenovec and pembrolizumab prices were informed by 2023 U.S. pricing compendia. Sensitivity analyses were performed. Results: Compared to pembrolizumab, nadofaragene firadenovec resulted in an ICER of $123,725 per QALY gained. The incremental cost was $24,194 (nadofaragene firadenovec: $374,280; pembrolizumab: $350,086) and the incremental QALYs were 0.196 (nadofaragene firadenovec: 4.560; pembrolizumab: 4.364). The cumulative drug acquisition and administration costs for nadofaragene firadenovec and pembrolizumab were $181,134 and $141,954 respectively, and AE costs were $248 and $2,749 and medical costs associated with health states were $192,898 and $205,382, respectively. The ICERs for nadofaragene firadenovec remained cost-effective across a majority of the sensitivity analyses and simulations. Conclusions: The analysis suggests that nadofaragene firadenovec is cost-effective compared to pembrolizumab for the treatment of high-risk, BCG unresponsive NMIBC with CIS ± Ta/T1 at a willingness to pay of $150,000/QALY.