Simcere Zaiming Pharmaceutical Co., Ltd.

Simnotrelvir is a small-molecule highly specific 3C-like protease inhibitor for anti-SARS-CoV-2 and was approved as a combination drug with ritonavir (simnotrelvir/ritonavir) in China. Simnotrelvir is a substrate of cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp), and a weak inhibitor of CYP3A. Ritonavir is a substrate and inhibitor of CYP3A and an inhibitor of P-gp. Hence, the drug-drug interaction potential of simnotrelvir/ritonavir should be investigated.

This drug-drug interaction study was an open-label, fixed-sequence, two-period phase I clinical trial in Chinese healthy adult subjects, divided into three cohorts, including simnotrelvir/ritonavir co-administrated with a strong CYP3A and P-gp inhibitor (itraconazole) and inducer (rifampicin), and with a specific CYP3A substrate (midazolam).

The results demonstrated that compared with administration of simnotrelvir/ritonavir alone, the co-administration with itraconazole increased the geometric least-square mean ratio (GMR) of the expose (area under the plasma concentration-time curve from time zero to the lowest detectable plasma concentration [AUC_0-t]) of simnotrelvir by 25% (GMR 125%, 90% CI 114-137%), whereas co-administration with rifampicin significantly decreased the AUC_0-t of simnotrelvir by 81.5% (GMR 18.5%, 90% CI 16.4-20.9%). Notably, simnotrelvir/ritonavir increased the AUC_0-t of midazolam by 16.69-fold (GMR 1769%, 90% CI 1551-2018%). The co-administration of simnotrelvir/ritonavir and rifampicin caused the increased amount and severity of treatment-emergent adverse events, especially hepatotoxicity.

The co-administration of simnotrelvir/ritonavir with CYP3A and P-gp inhibitors can be safely used, whereas the co-administration with CYP3A and P-gp strong inducer should be avoided to minimize the risk of under-exposure. Co-administration of midazolam with simnotrelvir/ritonavir increased systemic exposure of midazolam.

gov Identifier: NCT05665647.

Precise measurement of the binding activity changes of therapeutic antibodies is important to determine the potential critical quality attributes (CQAs) in developability assessment at the early stage of antibody development. Here, we report a surface plasmon resonance (SPR)-based relative binding activity method, which incorporates both binding affinity and binding response and allows us to determine relative binding activity of antibodies with high accuracy and precision. We applied the SPR-based relative binding activity method in multiple forced degradation studies of antibody developability assessment. The current developability assessment strategy provided comprehensive, precise characterization of antibody binding activity in the stability studies, enabling us to perform correlation analysis and establish the structure-function relationship between relative binding activity and quality attributes. The impact of a given quality attribute on binding activity could be confidently determined without isolating antibody variants. We identified several potential CQAs, including Asp isomerization, Asn deamidation, and fragmentation. Some potential CQAs affected binding affinity of antibody and resulted in a reduction of binding activity. Certain potential CQAs impaired antibody binding to antigen and led to a loss of binding activity. A few potential CQAs could influence both binding affinity and binding response and cause a substantial decrease in antibody binding activity. Specifically, we identified low abundance Asn33 deamidation in the light chain complementarity-determining region as a potential CQA, in which all the stressed antibody samples showed Asn33 deamidation abundances ranging from 4.2% to 27.5% and a mild binding affinity change from 1.76 nM to 2.16 nM.

The use of bevacizumab has been hampered by safety concerns despite demonstrable progression-free survival (PFS) benefit in subjects with platinum-resistant ovarian cancer, highlighting the need for novel effective and safe antiangiogenic agents. This study aimed to characterize the tolerability, safety, and antitumor activities of escalating doses of anti-VEGF antibody suvemcitug plus chemotherapy in platinum-resistant ovarian cancer patients.

This open-label, dose-escalation trial enrolled adult patients (≥18 years) with platinum-resistant histologically or cytologically-confirmed epithelial ovarian, fallopian tube and primary peritoneal cancer. Eligible patients received paclitaxel or topotecan plus escalating doses of suvemcitug 0.5, 1, 1.5, or 2 mg/kg once every two weeks. The primary endpoints were safety and tolerability, and antitumor activities of suvemcitug.

Twenty-nine subjects received paclitaxel (n = 11) or topotecan (n = 18). No dose-limiting toxicities occurred. The most common adverse events of special interest were proteinuria (41.4%), hypertension (20.7%) and epistaxis (10.3%). No gastrointestinal perforations occurred. Nine subjects (31.0%, 95% CI 15.3-50.8) demonstrated investigators-confirmed objective response, including complete response in 1 and partial response in 8. The median PFS was 5.4 months (95% CI 2.2-7.4).

Suvemcitug demonstrated an acceptable safety profile and promising antitumor activities in platinum-resistant ovarian cancer patients, supporting its further clinical development.