Phase 2 Study of the PD-1 Inhibitor Serplulimab plus the Bevacizumab Biosimilar HLX04 in Patients with Previously Treated Advanced Hepatocellular Carcinoma

First-line serplulimab in metastatic colorectal cancer: Phase 2 results of a randomized, double-blind, phase 2/3 trial

BACKGROUND

Whether or not the addition of immunotherapy to current standard-of-care treatments can improve efficacy in proficient mismatch repair (pMMR)/microsatellite-stable (MSS) metastatic colorectal cancer (mCRC), the predominant type of mCRC, is unclear.

METHODS

This randomized, double-blind, phase 2 part of a phase 2/3 trial was conducted at 23 hospitals across China (ClinicalTrials.gov: NCT04547166). Patients with unresectable metastatic/recurrent colorectal adenocarcinoma and no prior systemic therapy were randomly assigned 1:1 to receive every-3-weeks intravenous serplulimab (300 mg) plus HLX04 (7.5 mg/kg) and XELOX (serplulimab group) or placebo (300 mg) plus bevacizumab (7.5 mg/kg) and XELOX (placebo group). The primary endpoint was independent radiology review committee (IRRC)-assessed progression-free survival (PFS). Secondary endpoints included other efficacy endpoints and safety.

FINDINGS

Between July 16, 2021, and January 20, 2022, 114 patients were enrolled and randomly assigned to the serplulimab (n = 57) or placebo (n = 57) group. All patients had stage IV CRC, and 95.7% of the patients with available microsatellite instability (MSI) status were MSS. With a median follow-up duration of 17.7 months, median PFS was prolonged in the serplulimab group (17.2 vs. 10.7 months; hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.31-1.14). Although the median overall survival (OS) was not reached for either group, a trend of an OS benefit was observed for the serplulimab group (HR, 0.77; 95% CI, 0.41-1.45). 36 (65.5%) and 32 (56.1%) patients in the serplulimab and placebo groups had grade ≥3 treatment-related adverse events, respectively.

CONCLUSIONS

Serplulimab plus HLX04 and XELOX exhibits promising efficacy and is safe and tolerable in patients with treatment-naive mCRC.

FUNDING

This work was funded by Shanghai Henlius Biotech, Inc.

Safety, Tolerability, and Preliminary Efficacy of Serplulimab, a Novel Anti-PD-1 Antibody, in Patients with Metastatic or Recurrent Solid Tumors: A Phase I Study

BACKGROUND

Serplulimab is a novel, recombinant, humanized, monoclonal, anti-programmed death 1 antibody with a similar or better affinity and pre-clinical antitumor activity than pembrolizumab and nivolumab.

OBJECTIVE

This phase I, open-label, dose-escalation study evaluated serplulimab in patients with advanced solid tumors. The second interim analysis of the dose-finding phase is reported here.

METHODS

Adult patients with histologically confirmed metastatic/recurrent solid tumors who had progressed on, or were intolerant to/clinically unsuitable for standard treatment, were enrolled. Four intravenous serplulimab dose levels were evaluated: 0.3, 1.0, 3.0, and 10.0 mg/kg every 2 weeks in 28-day cycles for up to 2 years. Primary endpoints were the incidence of treatment-emergent adverse events and the maximum tolerated dose.

RESULTS

By 27 July, 2020 (data cut-off), 29 patients with stage IV disease (34.5% with lung cancer) received one or more doses of serplulimab. One (3.4%) patient had completed treatment and 26 (89.7%) had discontinued from the study. The maximum tolerated dose was not reached. Twenty-two (75.9%) patients experienced treatment-emergent adverse events related to serplulimab, most frequently nausea (24.1%), with no notable differences in incidence between dose cohorts; of these, grade ≥ 3 events occurred in four (13.8%) patients. Pharmacokinetic data demonstrated minimal accumulation of serplulimab after repeated administration. Functional programmed death 1 blockade was observed across dose levels. Objective response and disease control rates were 8.0 and 60.0%, respectively.

CONCLUSIONS

Serplulimab was well tolerated and demonstrated antitumor activity. These data support further study of serplulimab in larger patient populations.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT03468751 (19 March, 2018).

Progress in the treatment of advanced hepatocellular carcinoma with immune combination therapy

Advanced hepatocellular carcinoma (HCC) is a severe malignancy that poses a serious threat to human health. Owing to challenges in early diagnosis, most patients lose the opportunity for radical treatment when diagnosed. Nonetheless, recent advancements in cancer immunotherapy provide new directions for the treatment of HCC. For instance, monoclonal antibodies against immune checkpoint inhibitors (ICIs) such as programmed cell death protein 1/death ligand-1 inhibitors and cytotoxic t-lymphocyte associated antigen-4 significantly improved the prognosis of patients with HCC. However, tumor cells can evade the immune system through various mechanisms. With the rapid development of genetic engineering and molecular biology, various new immunotherapies have been used to treat HCC, including ICIs, chimeric antigen receptor T cells, engineered cytokines, and certain cancer vaccines. This review summarizes the current status, research progress, and future directions of different immunotherapy strategies in the treatment of HCC.

A global phase 3 study of serplulimab plus chemotherapy as first-line treatment for advanced squamous non-small-cell lung cancer (ASTRUM-004)

Combining immunotherapy with chemotherapy can provide improved survival in advanced squamous non-small-cell lung cancer (NSCLC) patients without targetable gene alterations. 537 previously untreated patients with stage IIIB/IIIC or IV squamous NSCLC without targetable gene alterations were enrolled and randomized (2:1) to receive serplulimab 4.5 mg/kg or placebo, both in combination with nab-paclitaxel and carboplatin, intravenously in 3-week cycles. The primary endpoint of progression-free survival (PFS) was met at the first interim analysis. At the second interim analysis, PFS benefit was maintained in serplulimab-chemotherapy group (hazard ratio [HR] 0.53, 95% confidence interval [CI] 0.42-0.67). At the final analysis, serplulimab-chemotherapy significantly improved median OS compared to placebo-chemotherapy (HR 0.73, 95% CI 0.58-0.93; p = 0.010). Grade ≥3 serplulimab or placebo-related adverse events occurred in 126 (35.2%) and 58 (32.4%) patients, respectively. Our results demonstrate that adding serplulimab to chemotherapy significantly improves survival in advanced squamous NSCLC patients, with manageable safety.

Efficacy and safety of serplulimab plus nab-paclitaxel in previously treated patients with PD-L1-positive advanced cervical cancer: a phase II, single-arm study

Objective

We report the efficacy and safety of serplulimab, a novel humanized anti-programmed death-1 antibody, plus nanoparticle albumin-bound (nab)-paclitaxel in previously treated patients with programmed death ligand-1 (PD-L1)-positive advanced cervical cancer.

Methods

Patients diagnosed with PD-L1-positive (combined positive score ≥1) cervical cancer were enrolled in this single-arm, open-label, phase II study. They were given serplulimab 4.5 mg/kg for up to 2 years (35 dosing cycles) plus nab-paclitaxel 260 mg/m² for up to six cycles once every 3 weeks. Primary endpoints were safety and objective response rate (ORR) assessed by independent radiological review committee (IRRC) per RECIST version 1.1. Secondary endpoints included ORR assessed by the investigator, duration of response (DOR), progression-free survival (PFS), and overall survival (OS).

Results

Between December 2019 and June 2020, 52 patients were screened and 21 were enrolled. IRRC-assessed ORR was 57.1% (95% confidence interval [CI] 34.0-78.2%); 3 (14.3%) patients achieved complete response and 9 (42.9%) partial response. The median DOR was not reached (NR) (95% CI 4.1-NR). IRRC-assessed median PFS was 5.7 months (95% CI 3.0-NR), and median OS was 15.5 months (95% CI 10.5-NR). Investigator-assessed ORR was 47.6% (95% CI 25.7-70.2%). Seventeen (81.0%) patients experienced grade ≥3 treatment-emergent adverse events. Grade ≥3 adverse drug reactions were reported in 7 (33.3%) patients. Immune-related adverse events occurred in 12 (57.1%) patients.

Conclusions

In previously treated patients with PD-L1-positive advanced cervical cancer, serplulimab plus nab-paclitaxel provided durable clinical activity and a manageable safety profile.

Clinical trial registration

ClinicalTrials.gov, identifier NCT04150575.

Advances in the structural characterization of complexes of therapeutic antibodies with PD-1 or PD-L1

Antibody-based immune checkpoint blockade (ICB)-based therapeutics have become effective clinical applications for cancers. Applications of monoclonal antibodies (mAbs) to de-activate the PD-1-PD-L1 pathway could effectively reverse the phenotype of depleted activated thymocytes (T cells) to recover their anti-tumoral activities. High-resolution structures of the complexes of the therapeutic monoclonal antibodies with PD-1 or PD-L1 have revealed the key inter-molecular interactions and provided valuable insights into the fundamental mechanisms by which these antibodies inhibit PD-L1-PD-1 binding. Each anti-PD-1 mAb exhibits a unique blockade mechanism, such as interference with large PD-1-PD-L1 contacting interfaces, steric hindrance by overlapping a small area of this site, or binding to an N-glycosylated site. In contrast, all therapeutic anti-PD-L1 mAbs bind to a similar area of PD-L1. Here, we summarized advances in the structural characterization of the complexes of commercial mAbs that target PD-1 or PD-L1. In particular, we focus on the unique characteristics of those mAb structures, epitopes, and blockade mechanisms. It is well known that the use of antibodies as anti-tumor drugs has increased recently and both PD-1 and PD-L1 have attracted substantial attention as target for antibodies derived from new technologies. By focusing on structural characterization, this review aims to aid the development of novel antibodies targeting PD-1 or PD-L1 in the future.