Effect of different HER2 expression on the efficacy of immunotherapy for advanced urothelial carcinoma who failed the previous chemotherapy / 中华泌尿外科杂志

ABSTRACT

Objective:To explore the effect of different HER2 expression levels and gene amplification on the efficacy of immunotherapy in metastatic urothelial carcinoma (UC).Methods:The clinical data of 77 patients with metastatic UC who received immunotherapy from June 2017 to April 2021 after failure to the previous chemotherapy were analyzed retrospectively, including 49 males and 28 females with the median age of 62 years. The primary tumors located in bladder in 28 cases (36.4%), renal pelvis in 25 cases (32.5%) and ureter in 24 cases (31.2%). The common metastatic sites included lymph nodes (n = 45, 58.4%), lung (n = 40, 51.9%), bone (n = 20, 26.0%) and liver (n = 16, 20.8%). 27 patients with bladder UC received surgery on the primary tumors including radical cystectomy (n = 18), partial cystectomy (n = 4) and transurethral resection (n = 5). 43 patients with renal pelvis or ureteral UC received surgery on the primary tumors including radical nephroureterectomy (n = 38), local resection (n = 3) and palliative resection (n = 2). Postoperative intravesical chemotherapy was performed in 15 cases, adjuvant radiotherapy was performed in 6 cases. 3 patients who emerged postoperative bladder recurrence received local radiotherapy. 7 patients received radiotherapy and 1 case received microwave ablation to their metastatic sites. All patients had received first-line chemotherapy and 30 patients (40.0%) had received at least second-line treatment including 70 cases (90.9%) with platinum containing chemotherapy. All 77 patients received anti-PD-1 treatment. 38 patients received sequential regimen after failed to the anti-PD-1 therapy, including antibody-drug conjugate (n = 17), chemotherapy (n = 18) and chemotherapy combined with anti-angiogenesis drugs (n = 12). Immunohistochemical (IHC) staining was used to detect the expression level of HER2 protein in the tumor tissues (74 cases from primary tumors and 3 cases from metastatic tumors) obtained from the initial diagnosis. For patients with HER2 IHC (+ + ), the copy number (CN) of HER2 gene was detected by next-generation sequencing (NGS). HER2 copy number amplification [CN (+ )] was defined as CN ≥ 4, and HER2 copy number non-amplification [CN(-)] was defined as CN < 4. HER2 IHC (0) was defined as HER2 negative, IHC (+ ) or IHC (+ + ) / CN (-)was defined as HER2 low expression, while IHC (+ + ) / CN(+ ) and IHC (+ + + ) were defined as HER2 high expression. Chi-square test or Fisher exact test were used to evaluate the correlation between HER2 expression and objective response rate (ORR) after anti-PD-1 treatment. Kaplan-Meier method and log-rank test were used to compare the differences of median progression free survival (PFS) and overall survival (OS) under different HER2 expression status.Results:All the 77 patients received a median of 11 (range 2 - 45) doses of anti-PD-1 treatment with a median duration of treatment of 6.4 (range 1.5 - 47.8) months and the ORR was 33.8% (26/77). The median follow-up time was 30.9 months. The overall median PFS time was 5.8 (95% CI 3.0 - 8.6) months and the median OS time was 23.6 (95% CI 8.5 - 38.7) months. HER2 IHC tests were performed in 77 patients. HER2 IHC levels of (0), (+ ), (+ + ) and (+ + + ) were found in 33 (42.9%), 19 (24.7%), 20 (26.0%) and 5 (6.5%) patients, respectively. HER2 copy number was detected in 20 patients with IHC (+ + ), while 1 CN(+ ) and 19 CN(-) were found. The ORR of HER2 negative, low expression and high expression patients were 42.4% (14/33) vs. 31.6% (12/38) vs. 0 (0/6) ( P = 0.08), respectively. The median PFS of the three groups were 11.0 months, 3.7 months and 1.8 months, respectively, with significant differences in overall and pairwise comparison( P=0.001). The median OS of patients with HER2 negative and low expression after anti-PD-1 treatment were 23.6 months and 22.7 months, respectively, while the median OS of patients with HER2 high expression had not been reached, with no significant difference in the overall comparison ( P=0.623). Conclusions:For patients with metastatic UC received anti-PD-1 treatment, the PFS of patients with high HER2 expression was significantly worse than that of patients with low or negative HER2 expression. HER2 expression may have potential value in predicting the efficacy of immunotherapy for metastatic UC who failed the previous chemotherapy, which needs further research.