A phase II study of penpulimab, an anti-PD-1 antibody, in patients with relapsed or refractoryclassic Hodgkin lymphoma (cHL)

Characteristics of clinical trials of new oncology drugs approved in China

BACKGROUND

Since reforms were introduced to incentivize drug innovation in 2015, the Chinese pharmaceutical market has experienced unprecedented prosperity, with more new drugs than ever before, especially anticancer treatments. In 2021, Chinese regulatory agencies issued the new guideline for clinical research and development of antitumor drugs, triggering a series of responses on the drug market. Limited research has outlined the nature of the original new drugs in China to understand the dynamic response of the market.

METHODS

The objective of this article was to map the clinical development of approved new oncology drugs in China from 2015 to 2021 and differed from previous studies by focusing on original new drugs, using the United States as a benchmark, and elaborating the endogenous features of clinical trials.

RESULTS

Clinical trials conducted in China have risen to a level similar to that of the United States in many aspects of trial design, but there is still distance between the implementation and operational details of clinical trials. In the meantime, China has made significant breakthroughs in drug approval. Greater than 60% of novel anticancer drugs in China received accelerated approved for their first listing. Approximately 90% of the pivotal clinical trials supporting initial drug approval used surrogate measures as end points, and one half were nonrandomized or did not have a control group. However, duplicate development without evidence of a clinical advantage compared with current therapies was widely observed.

CONCLUSIONS

By presenting a multidimensional landscape of clinical trials and approvals in the real world, this review allows interested researchers, developers, and even regulators to understand what has been done and what should be done next in anticancer drug development in China.

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.

Pre-clinical efficacy of CD20-targeted chimeric antigen receptor T cells for non-Hodgkin's lymphoma

BACKGROUND

A 4-1BB/CD3-ζ-costimulated CAR-T against CD20 (CAR-T20) was subjected to a systemic efficacy evaluation in a cell co-culture model, and NOD-SCID IL-2 receptor gamma null mice (short for NSG mice) were xenografted with human Burkitt's lymphoma Raji cells.

METHODS

CAR-T20 cells were incubated with target cells (K562, K562 CD20 or Raji cells) at ratios of 10:1 and 5:1 for 24 h, and the killing rate was estimated by an LDH cytotoxicity assay. To evaluate the effect of CAR-T20 on the survival time of tumor-bearing animals, 30 NSG mice were employed, and Raji-Luc cells (5 × 10⁵ cells per mouse) were administered prior to CAR-T20 administration. The survival time, optical intensity of Raji-Luc cells, clinical symptoms, and body mass of the animals were observed. Another 144 male NSG mice were employed to investigate the proliferation and antitumor effects of CAR-T20. Human cytokine and murine cytokines were detected at 1, 7, 14, 21, 28, 42, 56 and 90 days post-CAR-T administration, while biochemistry index analysis, T-cell and CAR-T-cell detection in peripheral blood, and histopathological examination were performed at 14, 28, 56 and 90 days post-administration.

RESULTS

CAR-T20 cells had a specific killing effect on CD20-expressing cells in vitro. At a dose of 1 × 10⁶ per mouse or above, CAR-T20 prolonged the median survival time from 14 days to more than 3 months, inhibited the proliferation of Raji cells in mice, and alleviated the clinical manifestations and weight loss caused by the Raji-Luc cell load. CAR-T20 at a dose of 2 × 10⁶ per mouse or above inhibited the proliferation of Raji cells in mice for up to 111 days post-administration without recurrence. The numbers of T cells and CAR-T cells in the animals administered CAR-T20 increased significantly when Raji cells were markedly proliferated and subsequently decreased when Raji cells were predominantly inhibited. CAR-T20 increased human IFN-γ, murine TNF and murine IL-6 levels and decreased human IL-10 levels in tumor-bearing mice. The incidences of xenografted tumors in organs/tissues were also reduced effectively by CAR-T20.

CONCLUSION

The effective dose of CAR-T20 in mice starts from 1 × 10⁶ per mouse, equivalent to a clinical dose of 5 × 10⁶/kg. Together, our data support the clinical translation of CAR-T20 for R/R B-cell NHL patients.

Novel Agents For Relapsed and Refractory Classical Hodgkin Lymphoma: A Review

Classical Hodgkin lymphoma (cHL) is the most common type of HL that occurs mainly in people aged between 15–30 and over 55 years. Although its general prognosis is favorable, 10%–30% of patients with cHL will ultimately develop relapsed or refractory disease (r/r cHL). Improving the cure rate of r/r cHL has proven to be challenging. Some novel agents, such as brentuximab vedotin and immune checkpoint inhibitors, which have been used in conventional regimens for patients with r/r cHL in the past decade, have been shown to have good curative effects. This paper reviews the conventional regimens for patients with r/r cHL and focuses on the newest clinical trials and treatment measures to prolong prognosis and reduce adverse events. The evaluation of prognosis plays a vital role in analyzing the risk of relapse or disease progression; thus, finding new predictive strategies may help treat patients with r/r cHL more efficaciously.

Penpulimab, an Fc-Engineered IgG1 Anti-PD-1 Antibody, With Improved Efficacy and Low Incidence of Immune-Related Adverse Events

Background

IgG4 anbibodies are deficient in stability and may contribute to tumor-associated escape from immune surveillance. We developed an IgG1 backbone anti-programmed cell death protein-1 (PD-1) antibody, penpulimab, which is designed to remove crystallizable fragment (Fc) gamma receptor (FcγR) binding that mediates antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP) and proinflammatory cytokine release.

Methods

Aggregation of different anti-PD-1 antibodies was tested by size exclusion chromatography, and melting temperature midpoint (Tm) and aggregation temperature onset (Tagg) were also determined. The affinity constants of penpulimab for PD-1 and human FcγRs were measured by surface plasmon resonance and biolayer interferometry. ADCC and ADCP were determined in cellular assays and antibody-dependent cytokine release (ADCR) from human macrophages was detected by ELISA. Binding kinetics of penpulimab to human PD-1 was determined by Biacore, and epitope/paratope mapping of PD-1/penpulimab was investigated using x-ray crystallography. Additionally, patients from six ongoing trials were included for analysis of immune-related adverse events (irAEs).

Results

Penpulimab demonstrated better stability and a lower level of host-cell protein residue compared with IgG4 backbone anti-PD-1 antibodies. As expected, penpulimab exhibited no apparent binding to FcγRIa, FcγRIIa_H131, FcγRIIIa_V158 and FcγRIIIa_F158, elicited no apparent ADCC and ADCP activities, and induced no remarkable IL-6 and IL-8 release by activated macrophages in vitro. Penpulimab was shown in the co-crystal study to bind to human PD-1 N-glycosylation site at N58 and had a slower off-rate from PD-1 versus nivolumab or pembrolizumab. Four hundred sixty-five patients were analyzed for irAEs. Fifteen (3.2%) patients had grade 3 or above irAEs. No death from irAEs was reported.

Conclusions

IgG1 backbone anti-PD1 antibody penpulimab has a good stability and reduced host cell protein residue, as well as potent binding to the antigen. Fc engineering has eliminated Fc-mediated effector functions of penpulimab including ADCC, ADCP and reduced ADCR, which may contribute to its more favorable safety profile.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier: AK105-101: NCT03352531, AK105-201: NCT03722147, AK105-301: NCT03866980, AK105-202:NCT03866967, AK105-203: NCT04172571, AK105-204: NCT04172506.

Autoimmune hemolytic anemia in patients with relapsed Hodgkin's lymphoma after treatment with penpulimab, a monoclonal antibody against programmed death receptor-1

In August 2021, penpulimab, an anti-programmed cell death 1 (PD-1) monoclonal antibody, was approved in China for the treatment of adult patients with relapsed or refractory classic Hodgkin's lymphoma who completed at least second-line chemotherapy. Penpulimab is currently in clinical trials in China and Australia for the treatment of nasopharyngeal cancer and non-small cell lung cancer. Several clinical studies have shown that penpulimab is safe and effective, and no immune-related adverse events (irAEs) above grade 3 were observed. A 60-year-old woman with relapsed Hodgkin's lymphoma developed nausea and fatigue after receiving penpulimab monotherapy (200 mg every 2 weeks). Ten days after the second injection, the patient's condition worsened, and biochemical test results confirmed autoimmune hemolytic anemia (AIHA), with a hemoglobin level of 70 g/L (normal range, 115-150 g/L), an unconjugated bilirubin level of 19.08 µmol/L (normal range, 0-17 µmol/L), and positive direct antiglobulin test (DAT) results. On the same day, we treated her with prednisone (2 mg/kg), but her hemoglobin level continued to decline to 51 g/L one day after hormone therapy, so she received an intravenous infusion of washed red blood cells and underwent plasmapheresis, which eventually resolved the AIHA. Considering that the hemoglobin level was < 65 g/L and the irAE was grade 4, penpulimab was discontinued, and the symptoms of AIHA disappeared. From this event, we know that severe AIHA can occur after penpulimab use similar to other PD-1 antibodies. In this case, plasmapheresis showed a good therapeutic effect and should be used as a supplementary means when hormonal and immunosuppressive therapies cannot provide rapid symptom relief. In addition, we recommend regular direct antiglobulin testing, as well as haptoglobin, lactate dehydrogenase and other hemolysis-related laboratory tests, in patients prescribed penpulimab and similar drugs for the early diagnosis and treatment of AIHA.

Antibodies to watch in 2022

In this 13th annual installment of the annual 'Antibodies to Watch' article series, we discuss key events in commercial antibody therapeutics development that occurred in 2021 and forecast events that might occur in 2022. Regulatory review of antibody therapeutics that target the SARS-CoV-2 coronavirus proceeded at an unprecedented pace in 2021, resulting in both emergency use authorizations and full approvals for sotrovimab, regdanvimab, REGEN-COV2, as well as others, in numerous countries. As of November 1, a total of 11 antibody therapeutics had been granted first approvals in either the United States or European Union in 2021 (evinacumab, dostarlimab loncastuximab tesirine, amivantamab, aducanumab, tralokinumab, anifrolumab, bimekizumab, tisotumab vedotin, regdanvimab, REGEN-COV2). The first global approvals of seven products, however, were granted elsewhere, including Japan (pabinafusp alfa), China (disitamab vedotin, penpulimab, zimberelimab), Australia (sotrovimab, REGEN-COV2), or the Republic of Korea (regdanvimab). Globally, at least 27 novel antibody therapeutics are undergoing review by regulatory agencies. First actions by the Food and Drug Administration on the biologics license applications for faricimab, sutimlimab, tebentafusp, relatlimab, sintilimab, ublituximab and tezepelumab are expected in the first quarter of 2022. Finally, our data show that, with antibodies for COVID-19 excluded, the late-stage commercial clinical pipeline of antibody therapeutics grew by over 30% in the past year. Of those in late-stage development, marketing applications for at least 22 may occur by the end of 2022.

Penpulimab: First Approval

Penpulimab (^®) is a humanised anti-programmed cell death 1 (PD-1) monoclonal antibody developed by Akeso Biopharma, in collaboration with Chia Tai Tianqing (a subsidiary of SinoBiopharm), for the treatment of various cancers, including Hodgkin's lymphoma, nasopharyngeal cancer, non-small cell lung cancer (NSCLC) and solid tumours. Penpulimab is an immunoglobulin G1 monoclonal antibody engineered to completely eliminate Fcγ receptor binding and Fc-mediated effector functions that can compromise anti-tumour activity. In August 2021, penpulimab received its first approval in China for the treatment of adult patients with relapsed or refractory classic Hodgkin's lymphoma who have undergone at least second-line chemotherapy. Penpulimab is under regulatory review for nasopharyngeal cancer and NSCLC in China. Clinical studies of penpulimab are underway for various cancers in China and Australia. This article summarizes the milestones in the development of penpulimab leading to this first approval for relapsed or refractory classic Hodgkin's lymphoma.