Efficacy and Safety of neoadjuvant stereotactic body radiotherapy plus adebrelimab and chemotherapy for triple-negative breast cancer: A pilot study

Background Emerging data have supported the immunostimulatory role of radiotherapy, which could exert a synergistic effect with immune checkpoint inhibitors (ICIs). With proven effective but suboptimal efficacy of ICI and chemotherapy in triple-negative breast cancer (TNBC), we designed a pilot study to explore the efficacy and safety of neoadjuvant stereotactic body radiotherapy (SBRT) plus adebrelimab and chemotherapy in TNBC patients. Methods Treatment-naïve TNBC patients received two cycles of intravenous adebrelimab (20mg/kg, every 3 weeks), and SBRT (24Gy/3f, every other day) started at the second cycle, then followed by six cycles of adebrelimab plus nab-paclitaxel (125 mg/m2 on days 1 and 8) and carboplatin (area under the curve 6 mg/mL per min on day 1) every 3 weeks. The surgery was performed within 3-5 weeks after the end of neoadjuvant therapy. Primary endpoint was pathological complete response (pCR, ypT0/is ypN0). Secondary endpoints included objective response rate (ORR), residual cancer burden (RCB) 0-I and safety. Results 13 patients were enrolled and received at least one dose of therapy. 10 (76.9%) patients completed SBRT and were included in efficacy analysis. 90% (9/10) of patients achieved pCR, both RCB 0-I and ORR reached 100% with 3 patients achieved complete remission. Adverse events (AEs) all-grade and grade 3-4 occurred in 92.3% and 53.8%, respectively. 1 (7.7%) patient had treatment-related serious AEs. No radiation-related dermatitis or death occurred. Conclusions Adding SBRT to adebrelimab and neoadjuvant chemotherapy led to a substantial proportion of pCR with acceptable toxicities, supporting further exploration of this combination in TNBC patients. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Clinical trial number NCT05132790. ### Competing Interest Statement Yan Xia and Huajun Li are the employee of Jiangsu Hengrui Pharmaceuticals Co., Ltd. No other potential conflicts of interest were reported ### Clinical Trial Clinical trial number: [NCT05132790][1] ### Clinical Protocols ### Funding Statement This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Not Applicable The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by Institutional Review Board of Shengjing Hospital, China Medical University and performed, according to the Declaration of Helsinki and Good Clinical Practice guidelines. Written informed consent was obtained from each patient. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Not Applicable I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Not Applicable I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Not Applicable [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT05132790&atom=%2Fmedrxiv%2Fearly%2F2023%2F08%2F17%2F2023.08.14.23294091.atom