A Phase I Dose Escalation Study of the Safety, Tolerability, and Pharmacokinetics of Ipilimumab in Chinese Patients with Select Advanced Solid Tumors

Preclinical investigations and a first-in-human phase 1a trial of JS007, a novel anti-CTLA-4 antibody, in patients with advanced solid tumors

BACKGROUND

Blocking cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) shows substantial antitumor efficacy. Here, we report the preclinical data and outcomes of a first-in-human phase 1a trial of JS007, a novel anti-CTLA-4 antibody, in advanced solid tumors.

METHODS

In preclinical studies, both in vitro characteristics and in vivo characteristics of JS007 were investigated. The clinical trial included a dose escalation phase and a dose expansion phase. Eligible patients with previously treated advanced solid tumors were enrolled. In the dose escalation phase, JS007 was administered intravenously every 3 weeks at doses of 0.03, 0.3, 1, 3, and 10 mg/kg. Then, 3 and 10 mg/kg were chosen for the dose expansion phase. The primary endpoints included the maximum tolerated dose (MTD) of JS007 based on dose-limiting toxicities (DLTs) and safety.

RESULTS

JS007 could effectively bind to CTLA-4 and induce an immune response in vitro. Potent in vivo antitumor activity of JS007 was observed. Increased T cell infiltration and T regulatory (Treg) cell depletion in tumor microenvironment of cancer cell xenografts were detected after treated with JS007. Pharmacological analysis in experimental animals showed a dose-proportional increase in exposure. In the clinical trial, a total of 28 patients were treated with JS007 across 5 dose levels. No DLTs occurred. The MTD did not reach at the highest dose tested (10 mg/kg). Twenty-three (82.1%) patients experienced at least one treatment-related adverse event (TRAE). The incidence of Grade ≥ 3 TRAEs was 28.6% (8/28) with alanine aminotransferase increase (7.1%, 2/28) being the most frequently reported TRAE. No severe immune-related adverse event (irAE) occurred. Pharmacological profiles of JS007 in patients were similar to those in animal models. Serum concentration of JS007 showed a dose-dependent escalation, and the half-life of JS007 was 9.4 ~ 12.2 days. Treatment-induced anti-drug antibody was detected in 2 patients. The disease control rate was 50% (14/28), and the median overall survival was 14.7 months.

CONCLUSIONS

JS007 preliminarily demonstrates good tolerance and encouraging antitumor activity in patients with previously treated advanced solid tumors.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT05049265 (Sep 20, 2021).

Remodeling the tumor-immune microenvironment by anti-CTLA4 blockade enhanced subsequent anti-PD-1 efficacy in advanced nasopharyngeal carcinoma

Sequential immunotherapy has shown certain advantages in malignancy. Here, we aim to evaluate the efficacy of sequential anti-CTLA-4 and anti-PD-1 treatment for recurrent or metastatic nasopharyngeal carcinoma patients (R/M NPC). We retrospectively analysis 2 phase I trial of ipilimumab and camrelizumab in Chinese R/M NPC patients. These patients were initially treated with ipilimumab, a CTLA4 blockade, followed by anti-PD-1 treatment. We observed a durable tumor remission in these patients (mPFS: 12.3 months; mDoR: 20.9 months). Multimodal investigations of biopsy samples disclosed remodeling of tumor-immune microenvironment triggered by ipilimumab. In responders, we found increased tumoral PD-L1/PD-L2 expression and T-cell infiltration after ipilimumab treatment, accompanied by reduced stroma and malignant cell components. In contrast, non-responders exhibited increased B-cell infiltration and increased peripheral CD19 + B cells, suggesting a defective transition from memory B cells to plasma cells. This study proposes that sequential therapy can potentially enhance treatment efficacy in chemotherapy-resistant NPC patients and provides insights into how preexisting anti-CTLA4 blockade can influence subsequent anti-PD-1 efficacy by remodeling the TME. Additionally, our results highlight the need for therapeutic strategies targeting naïve/memory B cells.

Treatment-emergent antidrug antibodies related to PD-1, PD-L1, or CTLA-4 inhibitors across tumor types: a systematic review

BACKGROUND

Increased understanding of how the immune system regulates tumor growth has innovated the use of immunotherapeutics to treat various cancers. The impact of such therapies, including programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors, on the production of antidrug antibodies (ADAs) and their impact on outcomes, is poorly understood. This study aims to evaluate the clinical trial evidence on ADA incidence associated with PD-1, PD-L1, and CTLA-4 inhibitors in the treatment of cancer and to assess associations between treatment administered, ADA incidence, and treatment outcomes.

METHODS

Embase®, Medline®, and EBM Reviews were searched via the OVID® platform on February 15, 2022. Conference proceedings, clinical trial registries, and global regulatory and reimbursement body websites were also searched. Eligible publications included clinical trials enrolling patients receiving cancer treatment with either PD-1, PD-L1, or CTLA-4 reporting outcomes including incidence or prevalence of ADAs and the impact of immunogenicity on treatment safety and efficacy. Reference lists of eligible publications were also searched. The review was conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and evidence quality assessment was conducted using the appropriate Joanna Briggs Institute Critical Appraisal tool.

RESULTS

After screening 4160 records and reviewing 97 full publications, a total of 34 publications reporting on 68 trials were included. A further 41 relevant clinical trials were identified on ClinicalTrials.gov and a further 32 from searches of packaging inserts. In total, 141 relevant trials covering 15 different checkpoint inhibitors and 16 different tumor types were included. Across the included trials, atezolizumab was associated with the highest incidence of ADAs (29.6% of 639 patients), followed by nivolumab (11.2% of 2,085 patients). Combination checkpoint inhibitor treatment appeared to increase the rate of ADAs versus monotherapy. Only 17 trials reported on the impact of ADAs on treatment outcomes with mixed results for the impact of ADAs on treatment efficacy, safety, and pharmacokinetics.

CONCLUSIONS

Checkpoint inhibitors for the treatment of cancer are immunogenic, with the incidence of treatment-emergent ADAs varying between individual therapies. It remains unclear what impact ADAs have on treatment outcomes.