Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a rising threat for immunocompromised cancer patients. The reduced immune defense may be a result of the malignancy itself or a side effect of therapy. While many chemotherapies can severely diminish the effect of vaccines against SARS-CoV-2, the effect of radioligand therapy has not yet been studied so far. Methods: In our database, 64 patient records of patients with metastatic castration-resistant prostate cancer that were treated with PSMA-directed radioligand therapy (PRLT) were randomly selected and checked for specific information (vaccination status, past corona virus disease 2019 (COVID-19) infections, the period between PRLT and vaccination, and antibody titers). A total of 30 patient records had sufficient information to examine the interference between PRLT and the vaccination against SARS-CoV-2. Results: In the analyzed cohort, 96.7% of the patients achieved seroconversion after receiving-on average-the third (booster) vaccination against SARS-CoV-2 and two PRLT cycles with average administered activities of 16.1 ± 7.2 GBq (435.1 ± 194.6 mCi) of lutetium-177 and 13.7 ± 6.6 MBq (0.37 ± 0.18 mCi) of actinium-225 (as part of 'TANDEM therapies') per patient. Conclusions: In the reviewed population, neither the initial response nor the maintenance of a positive immune response against the SARS-CoV-2 virus was undesirably affected by PRLT. The seroconversion rate and the absolute immune titers (in many cases >25,000 BAU/mL) are comparable to the normal population. This result implies the clinically important conclusion that neither an initial nor a booster vaccination against COVID-19 must be postponed if a PRLT is planned (and vice versa).

Keywords: COVID-19; PSMA; SARS-CoV-2; clinical care; humoral response; immunization; prostate cancer; radioligand therapy; vaccination.

背景：严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）已成为免疫功能低下的癌症患者的日益威胁。降低的免疫力可能是由恶性肿瘤本身或治疗的副作用引起的。虽然许多化疗药物可以显著削弱针对 SARS-CoV-2 的疫苗效果，但放射配体治疗的影响尚未进行研究。方法：在我们的数据库中随机选取了 64 名接受 PSMA 导向放射配体治疗（PRLT）的转移性去势抵抗性前列腺癌患者的记录，并检查这些记录中的特定信息（疫苗接种状态、过去感染新冠病毒的情况、PRLT 和疫苗接种之间的时间间隔以及抗体滴度）。共有 30 名患者的记录提供了足够的信息以研究 PRLT 与 SARS-CoV-2 疫苗之间的相互作用。结果：在分析的队列中，96.7% 的患者在接受平均第三次（加强剂）SARS-CoV-2 疫苗接种和两轮平均施用剂量为 16.1 ± 7.2 GBq (435.1 ± 194.6 mCi) 镧系-177 和 13.7 ± 6.6 MBq (0.37 ± 0.18 mCi) 锎系-225（作为“TANDEM 疗法”的一部分）后的患者中实现了血清转化。结论：在回顾的群体中，PRLT 并未对初始反应或针对 SARS-CoV-2 病毒的积极免疫反应的维持产生不利影响。血清转化率和绝对免疫滴度（许多情况下 >25,000 BAU/mL）与正常人群相当。这一结果意味着临床重要的结论是，如果计划进行 PRLT，则不必推迟初始或加强剂 COVID-19 疫苗接种（反之亦然）。

关键词：Covid-19；PSMA；SARS-CoV-2；临床护理；体液反应；免疫化；前列腺癌；放射配体治疗；疫苗接种。