The anti-PD-L1/CTLA-4 bispecific antibody KN046 in combination with nab-paclitaxel in first-line treatment of metastatic triple-negative breast cancer: a multicenter phase II trial.

This multicenter, phase II study (NCT03872791) aims to evaluate the efficacy and safety of the anti-PD-L1/CTLA-4 bispecific antibody KN046 combined with nab-paclitaxel in the first-line treatment of patients with metastatic triple-negative breast cancer (TNBC). The primary endpoints included objective response rate (ORR) and duration of response (DoR), and secondary endpoints included progression-free survival (PFS), overall survival (OS) rate, safety, and the correlation of PD-L1 status with clinical efficacy. This trial met pre-specified endpoints. 27 female patients were enrolled sequentially to receive KN046 in two dose levels (3 mg/kg or 5 mg/kg). Among the 25 evaluable patients, the ORR achieved 44.0% (95% CI, 24.4% - 65.1%), and the median DoR was not mature. The median PFS reached 7.33 months (95%CI, 3.68 - 11.07 months), and the median OS was 30.92 months (95%CI, 14.75 - NE months). In PD-L1 positive patients, PFS was 8.61 months (versus 4.73 months) and the 2-year OS rate was 62.5% (versus 57.1%) compared to PD-L1 negative patients. Patients tolerated well the combination therapy. In general, KN046 combined with nab-paclitaxel showed favorable efficacy and survival benefits with tolerable toxicity in the first-line treatment of metastatic TNBC, especially PD-L1 positive, which is worth further investigation.

Phase I trial of KN046, a novel bispecific antibody targeting PD-L1 and CTLA-4 in patients with advanced solid tumors.

BACKGROUND: KN046 is a novel bispecific antibody targeting programmed death ligand 1 (PD-L1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4). This multicenter phase I trial investigated the safety, tolerability, pharmacokinetics (PK), and efficacy of KN046 in patients with advanced solid tumors. METHODS: Patients who failed standard treatment were included. KN046 was administered at doses of 1, 3, and 5 mg/kg every 2 weeks (Q2W), 5 mg/kg every 3 weeks (Q3W), and 300 mg Q3W based on the modified toxicity probability interval method in the dose-escalation phase; the recommended dose was used in the expansion phase. Primary objectives were maximum tolerated dose (MTD) and recommended phase II dose (RP2D) in escalation and preliminary efficacy in expansion. Secondary objectives included PK, pharmacodynamics, safety, and tolerability of KN046. We also explored biomarkers based on PD-L1 expression, multiplex immunofluorescence (mIF) staining, and RNAseq-derived nCounter platform. RESULTS: Totally, 100 eligible patients were enrolled, including 59 with nasopharyngeal carcinoma (NPC), 36 with epidermal growth factor receptor (EGFR)-mutated non-small-cell lung cancer (NSCLC), and those with other advanced solid tumors. The most common treatment-related adverse events (TRAEs) were rash (33.0%), pruritus (31.0%), and fatigue (20.0%). Grade ≥3 TRAEs were observed in 14.0% of participants. No dose-limiting toxicity occurred in the dose-escalation phase, and the MTD was not reached. The RP2D was determined as 5 mg/kg Q2W according to the pharmacokinetic-pharmacodynamic model, the preliminary exposure-response analysis, and the overall safety profile. Among 88 efficacy-evaluable participants, the objective response rate (ORR) was 12.5%, and the median duration of response was 16.6 months. In the NPC subgroup, the ORR was 15.4%, and the median overall survival (OS) was 24.7 (95% CI 16.3 to not estimable) months. In the EGFR-mutant NSCLC subgroup, the ORR was 6.3%. mIF analysis results showed patients with high CD8 expression showed longer median OS (27.1 vs 9.2 months, p=0.02); better prognosis was observed in patients with high CD8 and PD-L1 expression. CONCLUSIONS: KN046 was well tolerated and showed promising antitumor efficacy in advanced solid tumors, especially in patients with NPC. The combination of both CD8 and PD-L1 expression improved the prediction of KN046 response. TRIAL REGISTRATION NUMBERS: NCT03733951 .

Mitophagy-lysosomal pathway is involved in silver nanoparticle-induced apoptosis in A549 cells.

With the increasing use of silver nanoparticles (AgNPs) in biological materials, the cytotoxicity caused by these particles has attracted much attention. However, the molecular mechanism underlying AgNP cytotoxicity remains unclear. In this study, we aimed to systematically investigate the toxicity induced by AgNP exposure to the lung adenocarcinoma A549 cell line at the subcellular and signaling pathway levels and elucidate the related molecular mechanism. The survival rate of cells exposed to AgNPs at 0, 20, 40, 80, and 160 µg/mL for 24 or 48 h decreased in a dose- and time-dependent manner. AgNPs induced autophagy and mitophagy, determined by the transmission electron microscopy investigation and upregulation of LC3 II/I, p62, PINK1, and Parkin expression levels. AgNP treatment induced lysosomal injury, including the decline of lysosomal membrane integrity and increase in cathepsin B level. The decreased in mitochondrial membrane potential, along with upregulation of cytochrome c, caspases 9 and 3, and BAX/BCL2, further suggested that mitochondrial injury were involved in AgNP-induced apoptosis. In addition, mitochondrial injury may further lead to excessive production of reactive oxygen species and oxidative/ antioxidant imbalance. The results suggested that AgNPs could regulate autophagy via mitochondrial and lysosome injury in A549 cells. The information of the molecular mechanism will provide an experimental basis for the safe application of nanomaterials.

Silver nanoparticles modulate mitochondrial dynamics and biogenesis in HepG2 cells.

Silver nanoparticles (AgNPs) are inevitably released into the environment owing to their widespread applications in industry and medicine. The potential of their toxicity has aroused a great concern. Previous studies have shown that AgNPs exposure in HepG2 cells is primarily related to the damage of mitochondria, which includes induction of mitochondrial swelling and increase of intracellular levels of reactive oxygen species (ROS), the collapse of mitochondrial membrane potential and induction of apoptosis through a mitochondrial pathway. In this study, the effects of AgNPs exposure in HepG2 cells on mitochondrial dynamics and biogenesis were investigated. AgNPs were found to induce mitochondrial morphological and structural alterations. The expressions of key proteins (Drp1, Fis1, OPA1, Mff, Mfn1, and Mfn2) related to mitochondrial fission/fusion event were changed. Especially the expression of fission-related protein 1 (p-Drp1) (Ser616) was significantly up-regulated, whereas the expression of mitochondrial biogenesis protein (PGC-1α) was reduced in AgNP-treated cells. Concomitantly, the expression of autophagy marker proteins (LC3B and p62) was increased. The results suggested that AgNPs could trigger cytotoxicity by targeting the mitochondria, resulting in the disruption of mitochondrial function, damage to the mitochondrial structure and morphology, interfering in mitochondrial dynamics and biogenesis. The mitochondria could be a critical target of AgNPs in cells. The functions of mitochondria could be used for assessing the cytotoxic effects associated with AgNPs in cells.

Cytotoxicity and apoptosis induced by silver nanoparticles in human liver HepG2 cells in different dispersion media.

Silver nanoparticles (Ag NPs) have been widely used in medical and healthcare products owing to their unique antibacterial activities. However, their safety for humans and the environment has not yet been established. This study evaluated the cellular proliferation and apoptosis of Ag NPs suspended in different solvents using human liver HepG2 cells. The ionization of Ag NPs in different dispersion media [deionized water, phosphate-buffered saline (PBS), saline and cell culture] was measured using an Ag ion selective electrode. The MTT assay was used to examine the cell proliferation activities. The effects of Ag NPs on cell cycle, induction of apoptosis, production of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were analyzed using flow cytometry. The degree of Ag NPs ionization differed with dispersion media, with the concentrations of silver ions in deionized water being the highest in all suspensions. Ag NPs could inhibit the viability of HepG2 cells in a time- and concentration-dependent manner. Ag NPs (40, 80 and 160 µg ml(-1)) exposure could cause cell-cycle arrest in the G2/M phase, significantly increasing the apoptosis rate and ROS generation, and decreasing the MMP in HepG2 cells more sensitive to deionized water than in cell culture. These results suggested that the cellular toxicological mechanism of Ag NPs might be related to the oxidative stress of cells by the generation of ROS, leading to mitochondria injury and induction of apoptosis. It also implies that it is important to assess the physicochemical properties of NPs in the media where the biological toxicity tests are performed.