The Combination of Icotinib Hydrochloride and Fluzoparib Enhances the Radiosensitivity of Biliary Tract Cancer Cells

Polyadenosine diphosphate-ribose polymerase inhibitors: advances, implications, and challenges in tumor radiotherapy sensitization

Polyadenosine diphosphate-ribose polymerase (PARP) is a key modifying enzyme in cells, which participates in single-strand break repair and indirectly affects double-strand break repair. PARP inhibitors have shown great potential in oncotherapy by exploiting DNA damage repair pathways, and several small molecule PARP inhibitors have been approved by the U.S. Food and Drug Administration for treating various tumor types. PARP inhibitors not only have significant antitumor effects but also have some synergistic effects when combined with radiotherapy; therefore they have potential as radiation sensitizers. Here, we reviewed the advances and implications of PARP inhibitors in tumor radiotherapy sensitization. First, we summarized the multiple functions of PARP and the mechanisms by which its inhibitors exert antitumor effects. Next, we discuss the immunomodulatory effects of PARP and its inhibitors in tumors. Then, we described the theoretical basis of using PARP inhibitors in combination with radiotherapy and outlined their importance in oncological radiotherapy. Finally, we reviewed the current challenges in this field and elaborated on the future applications of PARP inhibitors as radiation sensitizers. A comprehensive understanding of the mechanism, optimal dosing, long-term safety, and identification of responsive biomarkers remain key challenges to integrating PARP inhibition into the radiotherapy management of cancer patients. Therefore, extensive research in these areas would facilitate the development of precision radiotherapy using PARP inhibitors to improve patient outcomes.

PARP inhibitors combined with radiotherapy: are we ready?

PARP was an enzyme found in the nucleus of eukaryotic cells that played a crucial role in repairing damaged DNA. Recently, PARP inhibitors have demonstrated great potential in cancer treatment. Thus, the FDA has approved several small-molecule PARP inhibitors for cancer maintenance therapy. The combination of PARP inhibitors and radiotherapy relies on synthetic lethality, taking advantage of the flaws in DNA repair pathways to target cancer cells specifically. Studies conducted prior to clinical trials have suggested that the combination of PARP inhibitors and radiotherapy can enhance the sensitivity of cancer cells to radiation, intensify DNA damage, and trigger cell death. Combining radiotherapy with PARP inhibitors in clinical trials has enhanced the response rate and progression-free survival of diverse cancer patients. The theoretical foundation of PARP inhibitors combined with radiotherapy is explained in detail in this article, and the latest advances in preclinical and clinical research on these inhibitors for tumor radiotherapy are summarized. The problems in the current field are recognized in our research and potential therapeutic applications for tumors are suggested. Nevertheless, certain obstacles need to be tackled when implementing PARP inhibitors and radiotherapies in clinical settings. Factors to consider when using the combination therapy are the most suitable schedule and amount of medication, identifying advantageous candidates, and the probable adverse effects linked with the combination. The combination of radiotherapy and PARP inhibitors can greatly enhance the effectiveness of cancer treatment.

Development and internal validation of a nomogram for predicting survival of nonoperative EGFR-positive locally advanced elderly esophageal cancers

Purpose

This study aims to develop and validate a prediction model for non-operative, epidermal growth factor receptor (EGFR)-positive, locally advanced elderly esophageal cancer (LAEEC).

Methods

A total of 80 EGFR-positive LAEEC patients were included in the study. All patients underwent radiotherapy, while 41 cases received icotinib concurrent systemic therapy. A nomogram was established using univariable and multivariable Cox analyses. The model's efficacy was assessed through area under curve (AUC) values, receiver operating characteristic (ROC) curves at different time points, time-dependent AUC (tAUC), calibration curves, and clinical decision curves. Bootstrap resampling and out-of-bag (OOB) cross-validation methods were employed to verify the model's robustness. Subgroup survival analysis was also conducted.

Results

Univariable and multivariable Cox analyses revealed that icotinib, stage, and ECOG score were independent prognostic factors for LAEEC patients. The AUCs of model-based prediction scoring (PS) for 1-, 2-, and 3-year overall survival (OS) were 0.852, 0.827, and 0.792, respectively. Calibration curves demonstrated that the predicted mortality was consistent with the actual mortality. The time-dependent AUC of the model exceeded 0.75, and the internal cross-validation calibration curves showed good agreement between predicted and actual mortality. Clinical decision curves indicated that the model had a substantial net clinical benefit within a threshold probability range of 0.2 to 0.8. Model-based risk stratification analysis demonstrated the model's excellent ability to distinguish survival risk. Further subgroup analyses showed that icotinib significantly improved survival in patients with stage III and ECOG score of 1 (HR 0.122, P<0.001).

Conclusions

Our nomogram model effectively predicts the overall survival of LAEEC patients, and the benefits of icotinib were found in the clinical stage III population with good ECOG scores.

Itraconazole interferes in the pharmacokinetics of fuzuloparib in healthy volunteers

OBJECTIVE

Fuzuloparib is an orally administered poly [ADP-ribose] polymerase 1 (PARP1) inhibitor and has potential anti-tumor effect on ovarian cancer (such as fallopian tube cancer and primary peritoneal cancer) in China. As fuzuloparib is metabolized mainly by CYP3A4, we explored the effect of itraconazole, a strong CYP3A4 inhibitor, on a single oral dose of fuzuloparib in healthy male subjects.

METHODS

An open-label, single-arm, fixed sequence study was conducted. Twenty healthy adult males received one single dose of fuzuloparib (20 mg) with one dose administered alone and the other dose coadministered with itraconazole. Subjects received 200 mg QD itraconazole for 6 days during the study. Serials of blood samples were collected pre-dose of each fuzuloparib capsule administration and 48 h post-dose, and were used to analyze the PK parameters of fuzuloparib.

RESULTS

Coadministration of repeated 200 mg QD oral doses of itraconazole for 6 days increased fuzuloparib exposure by 1.51-fold and 4.81-fold for peak plasma concentration and area under the plasma concentration-time curve (AUC), respectively. Oral administration of 20 mg fuzuloparib alone or together with itraconazole was safe and tolerable in healthy male subjects.

CONCLUSION

The CYP3A4 inhibitor itraconazole has a significant influence on the PK behavior of fuzuloparib, suggesting to avoid using strong CYP3A4 inhibitors simultaneously with fuzuloparib. If it is necessary to use a strong CYP3A4 inhibitor, fuzuloparib would be discontinued and be restored to the original dose and frequency of administration after 5-7 half lives of CYP3A4 inhibitor stopped.

TRIAL REGISTRATION

http://www.chinadrugtrials.org.cn/index.html , CTR20191271.

Targeting the EGFR signaling pathway in cancer therapy: What's new in 2023?

INTRODUCTION

Epidermal growth factor receptor (EGFR) is frequently amplified, overexpressed, and mutated in multiple cancers. In normal cell physiology, EGFR signaling controls cellular differentiation, proliferation, growth, and survival. During tumorigenesis, mutations in EGFR lead to increased kinase activity supporting survival, uncontrolled proliferation, and migratory functions of cancer cells. Molecular agents targeting the EGFR pathway have been discovered, and their efficacy has been demonstrated in clinical trials. To date, 14 EGFR-targeted agents have been approved for cancer treatments.

AREAS COVERED

This review describes the newly identified pathways in EGFR signaling, the evolution of novel EGFR-acquired and innate resistance mechanisms, mutations, and adverse side effects of EGFR signaling inhibitors. Subsequently, the latest EGFR/panEGFR inhibitors in preclinical and clinical studies have been summarized. Finally, the consequences of combining immune checkpoint inhibitors and EGFR inhibitors have also been discussed.

EXPERT OPINION

As new mutations are threatened against EGFR-tyrosine kinase inhibitors (TKIs), we suggest the development of new compounds targeting specific mutations without inducing new mutations. We discuss potential future research on developing EGFR-TKIs specific for exact allosteric sites to overcome acquired resistance and reduce adverse events. The rising trend of EGFR inhibitors in the pharma market and their economic impact on real-world clinical practice are discussed.