Neoadjuvant chemoimmunotherapy combo shows promise in UTUC

An investigational regimen combining the PD-1 inhibitor toripalimab with chemotherapy showed promising clinical activity as a neoadjuvant treatment for patients with upper tract urothelial carcinoma (UTUC), according to data from a phase 2 trial presented at the 37th Annual European Association of Urology Congress.1

Among 11 patients who enrolled, 8 completed treatment and were preliminarily analyzed. Three of the 8 patients (37.5%) had a pathological complete response (pCR). The downstaging rate was 75% (6/8), and the disease control rate was 100%. All patients were alive and tumor free at the median follow-up of 5.8 months.

In this phase 2 multicenter study (NCT04099589), investigators planned to enroll 34 patients to receive toripalimab plus a gemcitabine/cisplatin chemotherapy regimen. Toripalimab was administered in 240 mg doses on day 1, and gemcitabine and cisplatin were administered in 1000 mg/m2 on day 1 and 8 and 75 mg/m2 on day 1, respectively. Each treatment cycle lasted 21 days. Neoadjuvant therapy was followed by radical nephroureterectomy and pelvic lymphadenectomy.

The primary end point of the study is pCR, and the secondary end points include downstaging rate, objective response rate, 3-year disease-free survival, 3-year overall survival, and safety. Patients were eligible to enroll in the study if their ureteroscopic biopsy confirmed a diagnosis of UTUC, their tumor tissue was PD-L1 positive, they had no previous chemotherapy or immunotherapy, they had no tumors in the bladder, they were between the ages of 18 and 75, and they had an ECOG performance score of 0 or 1.

The median age of the 8 patients was 64.5 years, and 62.5% (5/8) were men. Five of the 8 patients had ureteral cancer, 3 had renal pelvic cancer, and all 8 patients were considered high risk. All but 1 patient received 4 cycles of neoadjuvant therapy, and the remaining patient received 3 cycles. All patient tumors were unifocal. The median maximum tumor diameter was 2.5 cm (range, 1.5-5.1). Every patient had obstructed hydronephrosis. Multiparameter MRI confirmed clinical T staging, which found 7 patients were T3 and 1 patient was T2.

Seven patients had high-grade and 1 patient had low-grade urothelial carcinoma, according to the ureterorenoscopic biopsy. The median time from the end of neoadjuvant therapy to the start of radical nephroureterectomy was 7.3 weeks (range, 3.0-10.1).

Three patients (37.5%) had grade 3 chemotherapy-related adverse events (AEs) in the form of myelosuppression. No patients presented with grade 4 or grade 5 chemotherapy-related AEs. However, 2 patients had immune-related AEs in the form of grade 2 hypothyroidism and grade 2 adrenal insufficiency. No patients reported surgery-related complications, and the readmission rate was 0%.

The combination of toripalimab and chemotherapy displayed promising efficacy results. Safety was manageable, but immune-related AEs may occur and may result in prolonged treatment period.

Reference

1. Bi X, Shou J, Zhou A, et al. Neoadjuvant combined chemotherapy and immunotherapy for upper tract urothelial carcinoma: preliminary results of a phase II study. Presented at: 37th Annual European Association of Urology Congress; July 1-4, 2022; Amsterdam, Netherlands. Abstract A0301.