Efficacy and safety of anlotinib plus camrelizumab in treating retroperitoneal soft tissue sarcomas: a single-center retrospective cohort study

BACKGROUND: Conventional chemotherapy has limited therapeutic effects in retroperitoneal soft tissue sarcomas (RSTs), while anlotinib emerged as a novel multi-target tyrosine kinase inhibitor (TKI) for sarcomas. TKIs in combination with immunotherapy have demonstrated clinical activity in a variety of solid tumors. This study retrospectively analyzed the efficacy and safety of anlotinib plus camrelizumab for the treatment of RSTs. METHODS: Patients with RSTs who received anlotinib plus camrelizumab at Peking University Cancer Hospital Sarcoma Center were enrolled. Response assessment was conducted every 3 cycles of treatment according to response evaluation criteria in solid tumors version 1.1 (RECIST v1.1). Treatment-related adverse events (TRAEs) were evaluated by Common Terminology Criteria for Adverse Events (CTCAE) v5.0. Patients who had at least 1 response evaluation were analyzed. RESULTS: In all, 57 RSTs cases including 35 males and 22 females were analyzed, with a median age of 55 years. The pathological subtypes included 38 cases of L-sarcoma (liposarcoma and leiomyosarcoma), and 19 cases of non-L-sarcoma. Two patients (3.5%) had complete response (CR) and 13 patients (22.8%) had partial response (PR), with an objective response rate (ORR) of 26.3%. There were 31 (54.4%) and 11 (19.3%) patients with stable and progressive disease, respectively, with a disease control rate of 80.7%. Patients with non-L-sarcoma had a significantly better response rate than those with L-sarcoma (ORR: 52.6% vs. 13.2%; P=0.0031). After a median follow-up of 15.8 months, the median progression-free survival (PFS) was 9.1 months, with 3- and 6-month PFS rates of 83.6% and 60.8%, respectively. Patients with non-L-sarcoma had a significantly longer median PFS than did those with L-sarcoma (median PFS: 11.1 vs. 6.3 months; P=0.0256). TRAEs occurred in 28 (49.1%) patients, and 13 (22.8%) patients had grade 3–4 TRAEs. Hypertension (24.6%), hypothyroidism (19.3%), and palmar-plantar erythrodysesthesia syndrome (12.3%) were the most common TRAEs. CONCLUSIONS: The combination of anlotinib and camrelizumab demonstrated possible therapeutic efficacy and safety in the treatment of RSTs, especially for non-L-sarcomas.