Purpose

Aim of this study was to analyze the safety of prostate-specific membrane antigen radioligand therapy (PSMA-RLT) in patients with metastatic castration-resistant prostate cancer (mCRPC) with preexisting moderate to severe thrombocytopenia (CTCAE ≥ 2).

Materials and methods

Seventeen mCRPC patients with preexisting thrombocytopenia (platelet count < 75 × 10⁹/L) were included in this study. Patients received a median of 3 cycles of [¹⁷⁷Lu]Lu-PSMA-617 (range 1–6). The course of platelet cell count was closely monitored within and after the PSMA-RLT and analyzed statistically and according to CTCAE.

Results

No significant difference in platelet counts was observed between baseline and follow-up after each PSMA-RLT cycle: first cycle (54.18 ± 16.07 at baseline vs. 59.65 ± 39.16 at follow up [in × 10⁹/L], p= 0.834), second cycle (58.56 ± 16.43 vs. 107.1 ± 56.44, p = 0.203), and third cycle (60.38 ± 16.57 vs. 132.1 ± 80.43, p = 0.148), respectively. Similarly, baseline and end of treatment values, irrespective of the number of administered cycles, did not reveal a significant difference (54.18 ± 16.07 vs. 72.06 ± 71.9, p = 0.741). After the end of therapy, irrespective of the number of administered cycles, 29.4% of patients remained stable in terms of CTCAE scoring, 41.2% changed to a higher score and 29.4% improved to a lower score. We observed no critical bleeding events due to thrombocytopenia.

Conclusion

Despite the common consideration of marked preexisting thrombocytopenia as a contraindication for RLT, this study indicates feasibility of PSMA-RLT in patients with preexisting thrombocytopenia of grade ≥ 2, as in our preliminary experience, there was no RLT-induced significant deterioration of platelet cell count. Thus, patients with thrombocytopenia should not be categorically excluded from receiving PSMA-RLT.

中文翻译：

---

PSMA 放射配体治疗在既往存在中度至重度血小板减少症的 mCRPC 患者中的安全性

 目的

本研究的目的是分析前列腺特异性膜抗原放射配体疗法 （PSMA-RLT） 在既往存在中度至重度血小板减少症 （CTCAE ≥ 2） 的转移性去势抵抗性前列腺癌 （mCRPC） 患者中的安全性。

 材料和方法

本研究纳入 17 例既往存在血小板减少症 （血小板计数 < 75 × 10⁹/L） 的 mCRPC 患者。患者接受 3 个周期的 [¹⁷⁷Lu]Lu-PSMA-617 （范围 1-6） 的中位治疗。在 PSMA-RLT 内和之后密切监测血小板细胞计数的进程，并根据 CTCAE 进行统计分析。

 结果

在每个 PSMA-RLT 周期后，基线和随访之间血小板计数未观察到显著差异：第一个周期 （基线时 54.18 ± 16.07 vs. 59.65 ± 39.16 [× 10⁹/L]，p= 0.834），第二个周期 （58.56 ± 16.43 vs. 107.1 ± 56.44，p = 0.203）和第三个周期 （60.38 ± 16.57 vs. 132.1 ± 80.43，p = 0.148） 的 S Package。同样，无论给药周期的数量如何，基线和治疗结束值都没有显示出显着差异 （54.18 ± 16.07 vs. 72.06 ± 71.9，p = 0.741）。 治疗结束后，无论给药周期数如何，29.4% 的患者在 CTCAE 评分方面保持稳定，41.2% 的患者变为较高评分，29.4% 的患者改善为较低评分。我们没有观察到血小板减少症引起的严重出血事件。

 结论

尽管普遍认为先前存在的显著血小板减少症是 RLT 的禁忌症，但这项研究表明 PSMA-RLT 在先前存在的 ≥ 级血小板减少症患者中是可行的，因为根据我们的初步经验，没有 RLT 诱导的血小板细胞计数显着恶化。因此，血小板减少症患者不应被明确排除在接受 PSMA-RLT 之外。