Phase I Pharmacokinetic Study of Nivolumab in Korean Patients with Advanced Solid Tumors

Agent-Based Modelling Reveals the Role of the Tumor Microenvironment on the Short-Term Success of Combination Temozolomide/Immune Checkpoint Blockade to Treat Glioblastoma

Glioblastoma is the most common and deadly primary brain tumor in adults. All glioblastoma patients receiving standard-of-care surgery-radiotherapy-chemotherapy (i.e., temozolomide (TMZ)) recur, with an average survival time of only 15 months. New approaches to the treatment of glioblastoma, including immune checkpoint blockade and oncolytic viruses, offer the possibility of improving glioblastoma outcomes and have as such been under intense study. Unfortunately, these treatment modalities have thus far failed to achieve approval. Recently, in an attempt to bolster efficacy and improve patient outcomes, regimens combining chemotherapy and immune checkpoint inhibitors have been tested in trials. Unfortunately, these efforts have not resulted in significant increases to patient survival. To better understand the various factors impacting treatment outcomes of combined TMZ and immune checkpoint blockade, we developed a systems-level, computational model that describes the interplay between glioblastoma, immune, and stromal cells with this combination treatment. Initializing our model to spatial resection patient samples labeled using imaging mass cytometry, our model's predictions show how the localization of glioblastoma cells, influence therapeutic success. We further validated these predictions in samples of brain metastases from patients given they generally respond better to checkpoint blockade compared with primary glioblastoma. Ultimately, our model provides novel insights into the mechanisms of therapeutic success of immune checkpoint inhibitors in brain tumors and delineates strategies to translate combination immunotherapy regimens more effectively into the clinic. SIGNIFICANCE STATEMENT: Extending survival times for glioblastoma patients remains a critical challenge. Although immunotherapies in combination with chemotherapy hold promise, clinical trials have not shown much success. Here, systems models calibrated to and validated against patient samples can improve preclinical and clinical studies by shedding light on the factors distinguishing responses/failures. By initializing our model with imaging mass cytometry visualization of patient samples, we elucidate how factors such as localization of glioblastoma cells and CD8+ T cell infiltration impact treatment outcomes.

Increased death and exhaustion of CD69high T cells and NK cells are associated with PD-1 antibody application in the in vitro co-culture system

Background

The application of PD-1 monoclonal antibody (mAb) helps to treat non-small cell lung cancer, but acquired resistance has emerged in clinical practice. We tested the hypothesis that acquired resistance of anti-PD-1 immunotherapy is linked to death and exhaustion of activated T and NK cell.

Methods

The co-culture system of HCC827 cells and peripheral mononuclear cells (PBMCs) was established to evaluate the effect of PD-1 mAb on the death rate and exhaustion of T and NK cell. The predisposing role of CD69 for death and exhaustion was validated by using PHA-activated PBMCs of CD69^low NSCLC patients. The 10-colour/three laser flow cytometer was used to test related markers for cell activation, death and exhaustion.

Results

We found that PD-1 mAb increase the death and exhaustion of T cells and NK cells in a dose-dependent way when PBMCs from NSCLC patients whose the percentages of CD69⁺ cells in peripheral blood T cells were greater than 5% (CD69^high NSCLC patients). By analyzing PBMCs from healthy volunteers and CD69^low NSCLC patients, we found that T cells and NK cells can be induced to die by PD-1 mAb after PHA activation, and had a tendency to raise the rate of cell exhaustion.

Conclusions

Our findings imply that increased death and exhaustion of CD69^high T cells and NK cells are associated with ineffective anti-PD-1 immunotherapy in lung cancer. The CD69 expression of T cells and NK cells may be developed as a potential predictor for acquired resistance of anti-PD-1 immunotherapy. These data may provide ideas to guide individualized medication of PD-1 mAb in NSCLC patients.

Prognostic impact of pneumonitis after durvalumab therapy in patients with locally advanced non-small cell lung cancer

Background. Prognostic data on Japanese patients receiving durvalumab after chemoradiotherapy (CRT) for locally advanced non-small cell lung cancer (LA-NSCLC) are insufficient. Whether pneumonitis has prognostic implications in patients with LA-NSCLC who have received durvalumab also remains unclear. Methods. We retrospectively assessed the data of 82 consecutive patients who had received durvalumab after CRT at our institution between May 2018 and August 2020. A multi-state model was used to establish the associations between co-variables and progression-free survival (PFS). Results. The median observation period for all the censored cases was 14.5 months (5.7–28.9 months), the median PFS was 22.7 months, and the 12-month PFS rate was 62.3% (95% CI: 50.2%-72.3%). The median percentage of the lung volume receiving a radiation dose in excess of 20 Gray (V20) was 22% (4%-35%). Thirteen patients (16%) had Grade 1 pneumonitis before receiving durvalumab, and 62 patients developed pneumonitis after durvalumab (Grades 1, 2, and 3 in 25 [30%], 32 [39%], and 4 [5%], respectively). Twenty-four patients (29%) completed the 1-year durvalumab treatment period, 16 patients (20%) were continuing to receive treatment, and 42 (51%) had discontinued treatment. In a multi-state analysis, patients with pneumonitis before durvalumab therapy had a poorer PFS than those without pneumonitis (HR: 4.29, p = 0.002). The development of Grade 2 or higher pneumonitis after durvalumab was not a significant prognostic factor for PFS (HR: 0.71, p = 0.852). Conclusion. Grade 2 or higher pneumonitis after durvalumab was not a prognostic factor of PFS in LA-NSCLC patients received durvalumab.

Distribution of mucosal PD-1 expressing T cells in patients with colitis of different etiologies

BACKGROUND

Immunotherapy, targeting programmed death-1 (PD-1) enhances antitumor T-cell activity in patients with malignancies. Blocking PD-1 or its ligand may lead to fulminant colitis as serious adverse event in these patients. Since little is known of the presence and role of PD-1⁺T cells in colitis of different etiologies, we determined PD-1⁺T cells in mucosal specimens of patients with inflammatory bowel disease, infectious colitis (InfC), immunotherapy-related colitis (ImC) and healthy controls (HC).

METHODS

Newly diagnosed patients with ulcerative colitis (UC, n = 73), Crohn's disease (CD, n = 50), InfC (n = 5), ImC (n = 8) and HC (n = 8) were included. Baseline inflamed colonic biopsies were studied with immunohistochemistry and flowcytometry.

RESULTS

Using immunohistochemistry, PD-1 was not present on lymphocytes in the epithelium of all patients, nor in HC. The percentage PD-1⁺ of all lymphocytes in the lamina propria was 40% in UC, 5% in InfC, 3% in ImC and 0% in HC. Flowcytometry showed significant higher percentages of PD-1⁺T cells in inflamed biopsy specimens of UC patients (22%) compared to all other groups: CD patients (13%), InfC (12%), ImC (5%) and HC (6%).

CONCLUSION

There are relevant differences in distribution and frequencies of mucosal PD-1⁺ T-cell subsets in patients with UC, CD, InfC and ImC, supporting the hypothesis that these types of colitis are driven by different immunological pathways. The increased numbers of PD-1⁺ and PD-L1⁺ lymphocytes in the colonic mucosa of UC patients suggest that the PD-1/PD-L1 pathway might be more activated in UC than in CD.

Treatment-Related Serious Adverse Events of Immune Checkpoint Inhibitors in Clinical Trials: A Systematic Review

Background

Immune Checkpoint Inhibitors (ICI) have been progressively used in cancer treatment and produced unique toxicity profiles. This systematic review aims to comprehend the patterns and occurrence of treatment-related adverse events (trAEs) based on ICI.

Methods

PICOS/PRISMA methods were used to identify published English-language on PubMed, Web of Science, and Scopus from 2015 to 2020. Published clinical trials on ICI monotherapy, combined ICIs, and ICI plus other treatment with tabulated data on grade≥3 trAEs were included. Odds ratio (OR), χ² tests were used to analyze for effect size and associations.

Results

This review included 145 clinical trials involving 21786 patients. Grade 3-5 trAEs were more common with ICI when they were plused with other treatments compared with ICI monotherapy(54.3% versus 17.7%, 46.1%, p<0.05). Grade 3-5 trAEs were also more common with CTLA-4 mAbs compared with anti-PD-1 and anti-PD-L1 (34.2% versus 15.1%, 13.6%, p<0.05). Hyperthyroidism (OR 3.8, 95%CI 1.7–8.6), nausea (OR 3.7, 95%CI 2.5–5.3), diarrhea (OR 2.7, 95%CI 2.2–3.2), colitis (OR 3.4, 95%CI 2.7–4.3), ALT increase (OR 4.9, 95%CI 3.9–6.1), AST increase (OR 3.8, 95%CI 3.0–4.9), pruritus (OR 2.4, 95%CI 1.5–3.9), rash (OR 2.8, 95%CI 2.1–3.8), fatigue (OR 2.8, 95%CI 2.2–3.7), decreased appetite (OR 2.4, 95%CI 1.5–3.8), and hypophysitis (OR 2.0, 95%CI 1.2–3.3) were more frequent with combined ICIs. Diarrhea (OR 8.1, 95%CI 6.4–10.3), colitis (OR 12.2, 95%CI 8.7–17.1), ALT increase (OR 5.1, 95%CI 3.5–7.4), AST increase (OR 4.2, 95%CI 2.8–6.3), pruritus (OR 4.1, 95%CI 2.0–8.4), rash (OR 4.4, 95%CI 2.9–6.8), hypophysitis (OR 12.1, 95%CI 6.3–23.4) were more common with CTLA-4 mAbs; whereas pneumonitis (OR 4.7, 95% CI 2.1–10.3) were more frequent with PD-1 mAbs.

Conclusions

Different immune checkpoint inhibitors are associated with different treatment-related adverse events profiles. A comprehensive data in this systematic review will provide comprehensive information for clinicians.

Evaluating the efficacy and safety of immune checkpoint inhibitors by detecting the exposure-response: An inductive review

Immune checkpoint inhibitors (ICIs) have been demonstrated an effective treatment in multiple tumor type, which restore the immune response to against cancer cell. Currently, approved ICIs include anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4); anti-programmed cell death 1 (PD-1) and anti-programmed cell death ligand 1 (PD-L1) monoclonal antibodies (mAbs). In most these drugs, unique pharmacokinetic (PK) and pharmacodynamics (PD) have shown significant influence on clinical outcomes, which occurred by target-mediated drug concentration and time-varying drug clearance. An exposure-response (E-R) relationship has been used to describe the safety and efficacy of ICIs, and shown a plateaued E-R and time dependent changes in exposure. Using an enzyme linked immunosorbent assay (ELISA) or LC-MS/MS method to measure the peak concentration, trough concentration or area under the curve (AUC) of ICIs to assess the drug exposure. There are lots of covariates that have an influence on exposure, such as sex, clearance, body weight and tumor burden. In this review, we pooled data from studies of concentration or other pharmacokinetics parameter of mAbs to assess E-R in efficacy and safety.

Clinical Benefit-Risk Assessment of Nivolumab 240 mg Every 2 Weeks in Chinese Patients With Advanced and Metastatic Solid Tumors

Nivolumab 240 mg every 2 weeks is approved in China by the National Medical Product Agency for squamous cell carcinoma of the head and neck and gastric cancer, based on population pharmacokinetic (PPK) analyses and benefit-risk assessment of safety/efficacy in solid tumors, including Chinese and global populations. The aim of this assessment was to investigate exposure and risk for adverse events (AEs) with flat dosing compared with weight-based dosing. Nivolumab 240-mg and 3-mg/kg every-2-week exposures in Chinese patients were simulated using PPK modeling, and AEs in Chinese and pooled global populations were compared by dosing regimen, exposure, and weight. The 10-mg/kg every-2-week regimen was included because it is known to be well tolerated. Predicted nivolumab exposure in Chinese patients receiving 240 mg every 2 weeks was ∼25% higher versus 3 mg/kg every 2 weeks, but ∼60% lower versus 10 mg/kg every 2 weeks. Grade 3/4 AE incidence in Chinese patients receiving nivolumab 3 mg/kg every 2 weeks was similar with 240-mg every-2-week dosing and with patients from global populations treated with 3 or 10 mg/kg every 2 weeks. There was no trend toward increased AE incidence with high versus low nivolumab exposure or in global patients of varying body weight receiving 3 or 10 mg/kg every 2 weeks. Objective response rates were similar in Chinese and global patients with squamous and nonsquamous NSCLC. Results showed that benefit-risk profiles with nivolumab 240 mg every 2 weeks were similar to those of the 3-mg/kg every-2-week regimen in Chinese patients and global populations, providing an alternative treatment option to Chinese patients.

Dosage of anti-PD-1 monoclonal antibodies: a cardinal open question

Discovery and clinical development of monoclonal antibodies with the ability to interfere in the regulation of the immune response have significantly changed the landscape of oncology in recent years. Among the active agents licensed by the regulatory agencies, nivolumab and pembrolizumab are paradigmatic as the most relevant ones according to the magnitude of available data derived from the extensive preclinical and clinical experience. Although in both cases the respective data sheets indicate well-defined dosage regimens, a review of the literature permits to verify the existence of many issues still unresolved about dosing the two agents, so it must be considered an open question of potentially important consequences, in which to work to improve the effectiveness and efficiency of use.

HX008: a humanized PD-1 blocking antibody with potent antitumor activity and superior pharmacologic properties

Through reactivating tumor-infiltrating lymphocytes, therapeutics targeting programmed cell death protein 1 (PD-1) demonstrate impressive clinical efficacy in the treatment of multiple cancers. In this report, we characterize HX008, a humanized IgG4S228P anti-PD-1 monoclonal antibody with an engineered Fc domain, in a series of in vitro assays and in vivo studies. In vitro, HX008 binds to human PD-1 with high affinity and potently suppresses the interaction of PD-1 with PD-L1 and PD-L2. The lack of detectable binding to complement C1q and Fc gamma receptor III-a (FcγRIIIa) suggested that HX008 maintained reduced antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity. A comparable enhancement of cytokine production and NFAT-driven luciferase expression in cell-based assays confirmed that HX008 could promote T-cell function as effectively as Nivolumab. In vivo antitumor activity studies were carried out within two special tumor models: 1) the MiXeno model with an adoptive transfer of human peripheral blood mononuclear cells into HCC827 xenograft mice; and 2) HuGEMM with human PD-1 gene knock-in syngeneic MC38-bearing mice. In both models, HX008 significantly inhibits tumor growth and shows an effective antitumor response comparable to approved anti-PD-1 drugs. Furthermore, in a pharmacokinetics study performed in cynomolgus monkeys, HX008 induced no immune-related adverse events when administered at 10 mg/kg. Although some anti-drug antibody effects were observed in the primate PK study, the safety and favorable pharmacokinetics demonstrated in human clinical trials validate HX008 as a suitable candidate for cancer immunotherapy. Taken together, our studies provide a fairly thorough characterization of HX008 and strong support for its further clinical research and application.

Therapeutic Monoclonal Antibodies in Clinical Practice against Cancer

The importance of monoclonal antibodies in oncology has increased drastically following the discovery of Milstein and Kohler. Since the first approval of the monoclonal antibody, i.e. Rituximab in 1997 by the FDA, there was a decline in further applications but this number has significantly increased over the last three decades for various therapeutic applications due to the lesser side effects in comparison to the traditional chemotherapy methods. Presently, numerous monoclonal antibodies have been approved and many are in queue for approval as a strong therapeutic agent for treating hematologic malignancies and solid tumors. The main target checkpoints for the monoclonal antibodies against cancer cells include EGFR, VEGF, CD and tyrosine kinase which are overexpressed in malignant cells. Other immune checkpoints like CTLA-4, PD-1 and PD-1 receptors targeted by the recently developed antibodies increase the capability of the immune system in destroying the cancerous cells. Here, in this review, the mechanism of action, uses and target points of the approved mAbs against cancer have been summarized.

Efficacy and safety of nivolumab for renal cell carcinoma in patients over 75 years old from multiple Japanese institutes

PURPOSE

Despite nivolumab being increasingly used for treating metastatic renal cell carcinoma (mRCC), differing findings have been reported about its efficacy and safety in elderly patients. Thus, this study was aimed at evaluating nivolumab's efficacy and safety for treating mRCC in Japanese patients aged ≥ 75 years.

METHODS

From March 2013 to August 2019, 118 mRCC patients (89 men and 29 women) were treated with nivolumab. The objective response rates (ORRs) were compared between patients aged ≥ 75 and < 75 years. Progression-free survival (PFS), overall survival (OS), and adverse events (AEs) were also compared between the two age-groups.

RESULTS

The median follow-up duration after nivolumab initiation was 10 months. At the time of nivolumab initiation, 22 and 96 patients were aged ≥ 75 and < 75 years, respectively. Intergroup differences in patient characteristics except for age were not significant. Furthermore, intergroup differences in ORR (14 vs 23%; P = 0.367), PFS (HR 0.74, 95% CI 0.37-1.51; P = 0.414), and median OS (HR 1.29, 95% CI 0.68-2.46; P = 0.433) were not significant. The incidence of nivolumab discontinuation due to AEs was significantly higher in the ≥ 75 years group (27% vs 7%; P = 0.028), although the intergroup difference in the AE incidence rate was not significant (55% vs 43.8%; P = 0.535).

CONCLUSIONS

Nivolumab's effectiveness was comparable between the two patient groups, except for early AE-related discontinuation in the ≥ 75 year group.

KEYNOTE-032: A Randomized Phase I Study of Pembrolizumab in Chinese Patients with Advanced Non-Small Cell Lung Cancer

LESSONS LEARNED

Results of the KEYNOTE-032 study showed that the safety and pharmacokinetic profiles of pembrolizumab in Chinese patients were comparable with those observed in international studies, and antitumor activity was encouraging. These data support further evaluation of pembrolizumab to improve clinical outcomes in Chinese patients with advanced non-small cell lung cancer.

BACKGROUND

The KEYNOTE-032 study evaluated pembrolizumab pharmacokinetics and clinical outcomes in Chinese patients with locally advanced and/or metastatic non-small cell lung cancer (NSCLC) and prior treatment failure and/or ineligibility for standard therapy.

METHODS

Patients were randomized 1:1:1 to pembrolizumab 2 mg/kg, 10 mg/kg, or 200 mg every 3 weeks (up to 35 cycles). Safety and pharmacokinetics were primary endpoints; antitumor activity was a secondary endpoint.

RESULTS

A total of 42 of 44 randomized patients received pembrolizumab treatment (2 mg/kg, n = 14; 10 mg/kg, n = 13; 200 mg, n = 15). Treatment-related adverse events (AEs) occurred in 29 of 42 (69%) patients (grade 3-4, 4/42 [10%]); 5 (12%) had immune-mediated AEs and infusion reactions. Pembrolizumab single dose half-life following 2 mg/kg, 10 mg/kg, and 200 mg was 15.1, 15.8, and 12.3 days, respectively. Serum exposure at the doses studied (range, 2-10 mg/kg) was approximately linear; steady-state area under the curve_0-21 days (95% confidence interval [CI]) was 730.9 (627.4-851.6), 2,819.2 (2,009.4-3,955.4), and 931.0 (724.4-1,196.6) μg•day/mL, respectively. After 7.9 (range, 0.7-13.1) months median follow-up overall, objective response rate was 14.3% (95% CI, 5.4%-28.5%); median progression-free survival was 2.1 (95% CI, 2.1-4.2) months, and median overall survival was not reached (95% CI, 6.6 months-not reached).

CONCLUSION

Pembrolizumab had manageable toxicity, linear serum exposure, and encouraging antitumor activity in Chinese patients with advanced NSCLC.

Modeling Oncolytic Viral Therapy, Immune Checkpoint Inhibition, and the Complex Dynamics of Innate and Adaptive Immunity in Glioblastoma Treatment

Oncolytic viruses are of growing interest to cancer researchers and clinicians, due to their selectivity for tumor cells over healthy cells and their immunostimulatory properties. The immune response to an oncolytic virus plays a critical role in treatment efficacy. However, uncertainty remains regarding the circumstances under which the immune system either assists in eliminating tumor cells or inhibits treatment via rapid viral clearance, leading to the cessation of the immune response. In this work, we develop an ordinary differential equation model of treatment for a lethal brain tumor, glioblastoma, using an oncolytic Herpes Simplex Virus. We use a mechanistic approach to model the interactions between distinct populations of immune cells, incorporating both innate and adaptive immune responses to oncolytic viral therapy (OVT), and including a mechanism of adaptive immune suppression via the PD-1/PD-L1 checkpoint pathway. We focus on the tradeoff between viral clearance by innate immune cells and the innate immune cell-mediated recruitment of antiviral and antitumor adaptive immune cells. Our model suggests that when a tumor is treated with OVT alone, the innate immune cells' ability to clear the virus quickly after administration has a much larger impact on the treatment outcome than the adaptive immune cells' antitumor activity. Even in a highly antigenic tumor with a strong innate immune response, the faster recruitment of antitumor adaptive immune cells is not sufficient to offset the rapid viral clearance. This motivates our subsequent incorporation of an immunotherapy that inhibits the PD-1/PD-L1 checkpoint pathway by blocking PD-1, which we combine with OVT within the model. The combination therapy is most effective for a highly antigenic tumor or for intermediate levels of innate immune localization. Extreme levels of innate immune cell activity either clear the virus too quickly or fail to activate a sufficiently strong adaptive response, yielding ineffective combination therapy of GBM. Hence, we show that the innate and adaptive immune interactions significantly influence treatment response and that combining OVT with an immune checkpoint inhibitor expands the range of immune conditions that allow for tumor size reduction or clearance.

Benefit-risk assessment of nivolumab 240 mg flat dose relative to 3 mg/kg Q2W regimen in Japanese patients with advanced cancers

Nivolumab 3 mg/kg every 2 weeks (Q2W) has been approved in Japan for various cancers; however, use of a flat dose is expected to simplify dosing and administration. A quantitative clinical pharmacology approach was used to assess the benefit-risk profile of nivolumab 240 mg Q2W relative to the approved dose of nivolumab 3 mg/kg Q2W in Japanese patients. Three exposure-response safety analyses were performed for adverse events that led to discontinuation/death, were grade 3 or higher, and were immune-mediated and grade 2 or higher for Japanese patients diagnosed with one of multiple tumor types. Exposure-response analyses of efficacy were evaluated for overall survival and objective response rate. Exposures of nivolumab 240 mg Q2W were 37% higher than those of nivolumab 3 mg/kg Q2W in Japanese patients across the tumor types analyzed. Predicted safety profiles at the two doses differed by less than 2% across tumor types for adverse events leading to discontinuation/death, adverse events of grade 3 or higher, or immune-mediated adverse events of grade 2 or higher. In addition, the predicted 1-year and 2-year overall survival rates, the mean overall survival and the objective response rates were comparable between the doses regardless of the tumor type analyzed. Overall, these results demonstrated that the benefit-risk of nivolumab 240 mg Q2W was comparable to that of the previously approved 3 mg/kg Q2W dosing regimen, and was the basis for the approval of the 240 mg Q2W as an alternative dosing regimen for treatment in Japanese patients across multiple tumor types.

A Phase I/II Open-Label Study of Nivolumab in Previously Treated Advanced or Recurrent Nasopharyngeal Carcinoma and Other Solid Tumors

LESSONS LEARNED

Nivolumab treatment at doses of 3 mg/kg once every 2 weeks (Q2W), 240 mg Q2W, and 360 mg once every 3 weeks was well tolerated in the Chinese population, with no new safety signals identified.Comparison of intensive pharmacokinetic profiles of nivolumab at 3 mg/kg Q2W in Chinese versus global populations revealed no ethnic differences of nivolumab treatment.Nivolumab shows promising preliminary antitumor activity in nasopharyngeal carcinoma.

BACKGROUND

This phase I/II study investigated the safety and pharmacokinetics (PK) of nivolumab (anti-programmed cell death-1 monoclonal antibody) in Chinese patients with nasopharyngeal carcinoma (NPC) and other solid tumors.

METHODS

A dose evaluation phase (3 mg/kg once every 2 weeks [Q2W]) was followed by a cohort expansion phase (3 mg/kg Q2W or flat doses of 240 mg Q2W or 360 mg once every 3 weeks).

RESULTS

In the dose evaluation phase, 8/8 patients completed one cycle with no dose-limiting toxicities. At data cutoff, 46/51 patients were evaluable for safety (all cohorts). Treatment-related adverse events (TRAEs) occurred in 35 (76%) patients and were primarily grade 1-2; one patient (3 mg/kg Q2W) discontinued because of study drug toxicity. Intensive PK profiles at 3 mg/kg, 240 mg, and 360 mg were well characterized at single and multiple doses of nivolumab. An objective response was determined in six (6/46) patients, four (4/32) of whom had NPC tumors.

CONCLUSION

Nivolumab monotherapy at 3 mg/kg and flat doses of 240 mg and 360 mg were well tolerated in this Chinese patient population, with PK profiles at 3 mg/kg being similar to those of global patients. Preliminary efficacy results showed promising antitumor activity of nivolumab in advanced NPC.