520PA phase II study to evaluate abscopal effect by palliative radiation therapy in nivolumab treatment for pretreated non-small cell lung cancer (HANSHIN 0116)

Background While immune checkpoint inhibitors (ICIs) have been shown to be effective for non-small cell lung cancer (NSCLC), their monotherapeutic response rate (RR) is roughly 20%. It has been noted that local radiation therapy (RT) might potentially activate off-target antitumor effect, which is so called “abscopal effect” induced by immune-mediated mechanism. We evaluated whether palliative-RT induced abscopal effect, resulting in improvement of Nivolumab (Nivo) effectiveness. Methods Pretreated advanced NSCLC patients (pts) who were indicated for Nivo and scheduled for palliative-RT were started on RT within 10 days of administration of Nivo 3 mg/kg q2 weeks until attached document was revised to 240 mg/body q2 weeks. The primary endpoint was RR of non-irradiated tumor lesions. Results Twenty-eight pts were enrolled from May 2016 to January 2019. The study was terminated before completion of targeted initial sample size (n = 35), because of poor accrual. The median age was 67 years (range: 53-89). 15 pts were male. 21 pts had adenocarcinoma histology, 2 pts squamous histology, and 6 pts driver oncogene alterations. 25 pts were PS0/1, and 3 pts PS2. 14 pts were treated as 2nd-line, 2 pts as 3rd-line, and 12 pts as 4th-line or later. The median number of treatment cycles was 4 (range: 1-6). Median radiation dose was 30 Gy (range: 25-40), and 16 pts were irradiated on the bone, 5 pts on the adrenal grand, and 2 pts on the primary lesion. The objective RR of non-irradiated tumor lesions was 14.3% (95% CI: 1.3–27.2). Partial response (PR) was observed in 3 pts treated as 2nd-line (3/14, 21.4%), and 1 pt as 3rd-line (1/2, 50%). No PR was observed in pts treated as 4th-line or later (0/12, 0%). The median PFS was 2.7 months (95% CI: 1.0–3.5). No severe and specific adverse events (AEs) of Nivo in combination with RT were observed compared to historical data of Nivo monotherapy. Conclusions Although the sample size was small, cleared abscopal effect by palliative-RT was not observed in Nivo treatment. However, some pts well responded to Nivo with palliative-RT during early-lines of treatment (2nd/3rd-line). Further investigations in the early-lines are warranted to evaluate a substantial synergistic effect of RT with ICIs. Clinical trial identification UMI23646. Legal entity responsible for the study HANSHIN Oncology Group. Funding ONO Pharmaceutical Company. Disclosure A. Hata: Speaker Bureau / Expert testimony, Research grant / Funding (institution): Boehringer Ingelheim; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Eli Lilly; Speaker Bureau / Expert testimony, Research grant / Funding (institution): AstraZeneca; Speaker Bureau / Expert testimony: Chugai; Research grant / Funding (institution): MSD. M. Satouchi: Speaker Bureau / Expert testimony, Research grant / Funding (institution): AstraZeneca; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Boehringer Ingelheim; Speaker Bureau / Expert testimony, Research grant / Funding (institution): BMS; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Chugai; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Eli Lilly; Speaker Bureau / Expert testimony, Research grant / Funding (institution): MSD; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Novartis; Speaker Bureau / Expert testimony, Research grant / Funding (institution): ONO; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Pfizer; Research grant / Funding (institution): Takeda; Speaker Bureau / Expert testimony: Taiho. D. Harada: Honoraria (self): ONO; Honoraria (self): BMS. All other authors have declared no conflicts of interest.