Neoadjuvant apatinib plus camrelizumab in renal cell carcinoma with inferior vena cava tumor thrombus: Results of a phase II study.

4536 Background: Renal cell carcinoma (RCC) with inferior vena cava tumor thrombus (IVCTT) remains a surgically challenging condition, and evidence supporting neoadjuvant systemic therapy is still evolving. We conducted a phase II study to evaluate the efficacy and safety of apatinib combined with camrelizumab as neoadjuvant treatment in this population. Methods: This single-arm phase II trial enrolled patients with histologically confirmed, resectable RCC with IVCTT (cT3b-T4, N0-1, M0-1; ECOG performance status 0-1). Patients received camrelizumab 200 mg i.v. every 2 weeks for six cycles plus oral apatinib 250 mg once daily, followed by surgical resection when feasible. The primary endpoint was downgrading of Mayo level of tumor thrombus (TT). Secondary endpoints included TT response (RECIST 1.1), response of primary renal tumor, safety (CTCAE v5.0), progression-free survival, and overall survival. Results: Nine patients were included in the intention-to-treat analysis. TT response was observed in 4 patients (44.4%), with disease control achieved in 8 patients (88.9%); one patient (11.1%) experienced progression. Mayo level downgrading occurred in 3 patients (33.3%), all of whom subsequently underwent surgery. Overall, 7 of 9 patients (77.8%) successfully completed neoadjuvant therapy and underwent robotic-assisted radical nephrectomy with thrombectomy. For primary renal tumor, partial response was observed in 1 patient (11.1%), and stable disease in 8 patients (88.9%), resulting in a disease control rate of 100%. Treatment-related adverse events were manageable and consistent with known safety profiles, with grade ≥3 events including hypertension, proteinuria, pneumonitis, and immune-related myasthenia gravis. At a median follow-up of 45 weeks, survival outcomes remain immature. Conclusions: Neoadjuvant apatinib plus camrelizumab demonstrated promising antitumor activity and acceptable safety in patients with RCC and IVCTT, achieving meaningful TT response and Mayo level downgrading, thereby facilitating surgical resection. These findings support further investigation of neoadjuvant combination therapy in this high-risk population. Clinical trial information: ChiCTR2300069990. Patient baseline characteristics. Characteristic N=9 Median age, years, (IQR) 58 (54-66) Sex, n (%) Male 6 (67) Female 3 (33) ECOG PS, n (%) 0 7 (78) 1 2 (22) Clinical T stage, n (%) cT3b 2 (22) cT3c 3 (33) cT4 4 (44) Clinical N stage, n (%) cN0 3 (33) cN1 6 (67) Clinical M stage, n (%) cM0 3 (33) cM1 6 (67) Primary tumor size, cm (IQR) 12.4 (7.3-17.3) Length of the tumor thrombus, cm (IQR) 11.3 (7.2-13.8) Histological subtype on baseline biopsy, n (%) Clear cell RCC 8 (89) TFE3 translocation RCC 1 (11) Mayo level of TT at baseline I 0 II 4 (44) III