ABSTRACT
BACKGROUND: The role of immune checkpoint inhibitor (ICI) maintenance therapy in metastatic renal cell carcinoma (mRCC) is undefined. OBJECTIVE: To determine whether switch maintenance therapy with nivolumab improves clinical outcomes in patients with mRCC with tyrosine kinase inhibitor (TKI) sensitivity. DESIGN, SETTING, AND PARTICIPANTS: This open-label phase 2 trial randomized patients with a partial response or stable disease after 10-12-wk TKI induction therapy to either TKI or nivolumab maintenance. Key inclusion criteria were measurable disease, clear cell histology, Eastern Cooperative Oncology Group performance status (ECOG PS) 0-2, and adequate organ function. INTERVENTION: Intravenous nivolumab 8 × 240 mg every 2 wk, followed by 480 mg every 4 wk or sunitinib 50 mg (4-2 regimen) or pazopanib 800 mg once daily orally. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSES: The primary endpoint was overall survival (OS). Secondary endpoints were the objective response rate (ORR; Response Evaluation Criteria in Solid Tumors v1.1), progression-free survival (PFS), safety (Common Terminology Criteria for Adverse Events v4.03), and patient-reported outcomes (Functional Assessment of Cancer Therapy Kidney Symptom Index). The Kaplan-Meier method, two-sided log-rank tests, and Cox regression models were used for statistical analysis. RESULTS AND LIMITATIONS: Maintenance therapy was nivolumab for 25 patients (51.0%) and TKI for 24 (48.9%). The median age was 65 yr (range 35-79). Nine patients (18.4%) were female, 31 (63.3%) had ECOG PS of 0, and 15 (30.6%) had favorable risk. OS data are immature (17 deaths, 34.7%). The ORR was 20.0% (n = 5) for nivolumab and 52.2% (n = 12) for TKI. PFS was worse with nivolumab (hazard ratio 2.57, 95% confidence interval 1.36-4.89; p = 0.003). Grade ≥3 adverse events occurred in 14 patients (56.0%) with nivolumab and 17 (70.8%) with TKI. A major limitation is early termination of our study. CONCLUSIONS: TKI treatment achieved superior ORR and PFS in comparison to nivolumab maintenance therapy. Our data do not indicate a role for nivolumab switch maintenance in mRCC. PATIENT SUMMARY: Patients with metastatic kidney cancer who experienced a tumor response or disease stabilization after a short period of targeted treatment with a tyrosine kinase inhibitor did not benefit from a switch to the immunotherapy drug nivolumab. Patients who continued their original treatment achieved better responses and a longer time without disease progression. This trial is registered on EudraCT as 2016-002170-13 and on ClinicalTrials.gov as NCT02959554.
Subject(s)
Carcinoma, Renal Cell , Kidney Neoplasms , Aged , Female , Humans , Male , Carcinoma, Renal Cell/pathology , Kidney Neoplasms/pathology , Nivolumab/adverse effects , Protein Kinase Inhibitors/adverse effects , Adult , Middle AgedABSTRACT
Lactate metabolism variations are frequently encountered in mammalian cell culture processes, especially during process scale-up. In this study, we took a multipronged approach to investigate the impact of pH, pCO2 , osmolality, base addition, and mixing conditions on the observed lactate variations in a Chinese Hamster Ovary (CHO) fed-batch process at 2,000 L scale. Two cultivating methods, CO2 -controlled and pH-controlled, were used to decouple the individual and synergistic effects from those factors. The individual effects from pH, pCO2 , and osmolality on lactate consumption/reproduction in the stationary phase were insignificant in the ranges studied though the initial lactate production rates varied. In contrast, lactate metabolism was found to be impacted by an interaction between mixing conditions and CO2 accumulation. High CO2 accumulation and poor mixing led to lactate reproduction, whereas either low CO2 or improved mixing were sufficient to result in lactate consumption. Base addition was not required for pH control in the low CO2 conditions, and therefore lactate reproduction was correlated with base addition under poor mixing conditions. Under good mixing conditions, CO2 -triggered base addition did not significantly impact lactate reproduction. It is reasonable to postulate that increased mixing times further promoted lactate production during base addition. As lactate reproduction results in more base addition to maintain pH, a cycle could be formed between lactate production and base addition. As a remediation, we showed that such lactate reproduction could be eliminated by improving CO2 removal at 2,000 L scale. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:756-766, 2018.