892P - Camrelizumab plus dalpiciclib in anti-PD-1 refractory recurrent or metastatic nasopharyngeal carcinoma

Background

Most patients with recurrent/metastatic nasopharyngeal carcinoma (RM-NPC) have undergone prolonged immunotherapy as part of their initial and first-line treatment, resulting in a significant number of patients develop resistance to PD-(L)1 mAbs. The management of such patients presents a significant clinical challenge that demands urgent attention. CDK4/6 inhibitors，besides their effects on cell-cycle progression, have emerged as potent modulators of T cell immunity. This observation has prompted investigations into whether these agents can synergize with established T cell–targeting immunotherapies, such as PD-1 inhibitors. Thus, we sought to assess the efficacy and safety of camrelizumab plus dalpiciclib in patients with RM-NPC who are refractory to PD-1 inhibitors.

Methods

This multicenter phase II study enrolled patients with RM-NPC refractory to at least one line of systemic platinum-containing chemotherapy and anti-PD-(L)1 immunotherapy. The patients received camrelizumab 200 mg every 3 weeks and dalpiciclib 150 mg once daily for 3 weeks, followed by 1 week off in each 4-week cycle. The primary endpoint was objective response rate (ORR). Key secondary endpoints included disease control rate (DCR), progression-free survival (PFS), duration of response (DoR), overall survival (OS), and safety.

Results

Between September 1, 2022, and November 11, 2023, 34 patients were enrolled. The ORR was 32.4% (95% CI, 17.4–50.5), with 3 patients achieving complete response (CR). The DCR was 79.4% (95% CI, 62.1–91.3). The median DoR was 10.4 months (95% CI, 3.1–17.6), and the median PFS was 6.7 months (95% CI, 5.4–8.0). Treatment-related adverse events (TRAEs) of grade ≥3 were reported in 26 (76.5%) patients, with the most common being neutropenia, leukopenia, thrombocytopenia, and anemia. Most AEs are manageable, and no treatment-related deaths occurred.

Conclusions

Camrelizumab plus dalpiciclib exhibited encouraging efficacy and manageable toxicity in patients with RM-NPC refractory to frontline immunotherapy.

Clinical trial identification

NCT05724355. First Posted: February 13, 2023.

Editorial acknowledgement

Funding

National Natural Science Foundation of China Jiangsu Hengrui Medicine Company.

Disclosure

All authors have declared no conflicts of interest.