836P Safety and efficacy of XMT-1536 in ovarian cancer: A subgroup analysis from the phase I expansion study of XMT-1536, a NaPi2b antibody-drug conjugate

Antibody-Drug Conjugates-Evolution and Perspectives

Antineoplastic therapy is one of the main research themes of this century. Modern approaches have been implemented to target and heighten the effect of cytostatic drugs on tumors and diminish their general/unspecific toxicity. In this context, antibody-drug conjugates (ADCs) represent a promising and successful strategy. The aim of this review was to assess different aspects regarding ADCs. They were presented from a chemical and a pharmacological perspective and aspects like structure, conjugation and development particularities alongside effects, clinical trials, safety issues and perspectives and challenges for future use of these drugs were discussed. Representative examples include but are not limited to the following main structural components of ADCs: monoclonal antibodies (trastuzumab, brentuximab), linkers (pH-sensitive, reduction-sensitive, peptide-based, phosphate-based, and others), and payloads (doxorubicin, emtansine, ravtansine, calicheamicin). Regarding pharmacotherapy success, the high effectiveness expectation associated with ADC treatment is supported by the large number of ongoing clinical trials. Major aspects such as development strategies are first discussed, advantages and disadvantages, safety and efficacy, offering a retrospective insight on the subject. The second part of the review is prospective, focusing on various plans to overcome the previously identified difficulties.

Clinical and translational advances in ovarian cancer therapy

Ovarian cancer is an aggressive disease that is frequently detected at advanced stages and is initially very responsive to platinum-based chemotherapy. However, the majority of patients relapse following initial surgery and chemotherapy, highlighting the urgent need to develop new therapeutic strategies. In this Review, we outline the main therapeutic principles behind the management of newly diagnosed and recurrent epithelial ovarian cancer and discuss the current landscape of targeted and immune-based approaches.

The evolving landscape of antibody-drug conjugates in gynecologic cancers

Despite significant advances in the treatment of cervical, ovarian, and uterine cancers with the approvals of checkpoint and PARP inhibitors into standard treatment, patients with recurrent metastatic gynecologic malignancies still experience poor outcomes, and most of these patients will experience disease relapse. Once standard preferred treatments are exhausted, options have historically been limited to treatments associated with poor outcomes and notable toxicities. Consequently, novel therapies that are effective and well-tolerated are needed for patients with recurrent and metastatic gynecologic malignancies. Antibody-drug conjugates (ADCs) are a class of targeted therapies that are well established in several cancers including hematologic malignancies and some solid tumors. Significant strides in ADC technology and design have led to improvements in efficacy and safety with newer-generation ADCs. Consequently, ADCs are gaining traction in gynecologic cancers with the recent US Food and Drug Administration approvals of tisotumab vedotin in cervical cancer and mirvetuximab soravtansine in ovarian cancer. Many additional ADCs against various targets are being explored in patients with metastatic or recurrent gynecologic malignancies. The purpose of this review is to summarize the nuanced structural and functional properties of ADCs, while outlining opportunities for innovation. Further, we highlight the ADCs in clinical development for gynecologic malignancies, exploring how ADCs may be able to address the clinical care gap for patients with gynecologic cancers.

Targeting NaPi2b in ovarian cancer

Novel biomarkers are needed to direct new treatments for ovarian cancer, a disease for which the standard of care remains heavily focused on platinum-based chemotherapy. Despite the success of PARP inhibitors, treatment options are limited, particularly in the platinum-resistant setting. NaPi2b is a cell surface sodium-dependent phosphate transporter that regulates phosphate homeostasis under normal physiological conditions and is a lineage marker that is expressed in select cancers, including ovarian, lung, thyroid, and breast cancers, with limited expression in normal tissues. Based on its increased expression in ovarian tumors, NaPi2b is a promising candidate to be studied as a biomarker for treatment and patient selection in ovarian cancer. In preclinical studies, the use of antibodies against NaPi2b showed that this protein can be exploited for tumor mapping and therapeutic targeting. Emerging data from phase 1 and 2 clinical trials in ovarian cancer have suggested that NaPi2b can be successfully detected in patient biopsy samples using immunohistochemistry, and the NaPi2b-targeting antibody-drug conjugate under evaluation appeared to elicit therapeutic responses. The aim of this review is to examine literature supporting NaPi2b as a novel biomarker for potential treatment and patient selection in ovarian cancer and to discuss the critical next steps and future analyses necessary to drive the study of this biomarker and therapeutic targeting forward.

A review of recent advances on single use of antibody-drug conjugates or combination with tumor immunology therapy for gynecologic cancer

Immune checkpoint inhibitors have made significant progress in the treatment of various cancers. However, due to the low ICI responsive rate for the gynecologic cancer, ICI two-drug combination therapy tends to be a predominant way for clinical treatment. Antibody-drug conjugates, a promising therapeutic modality for cancer, have been approved by the FDA for breast cancer, lymphoma, multiple myeloma and gastric cancer. On September 2021, the FDA granted accelerated approval to tisotumab vedotin for patients with recurrent or metastatic cervical cancer. Currently, the role of therapy of ADCs on gynecologic tumors was also included in medication regimens. Now more than 30 ADCs targeting for 20 biomarkers are under clinical trials in the field, including monotherapy or combination with others for multiple lines of therapy. Some ADCs have been proved to enhance the antitumor immunity effect on both pre-clinical models and clinical trials. Therefore, combination of ADCs and ICIs are expected in clinical trials. In this review, we discuss current development of ADCs in gynecologic oncology and the combination effects of ICIs and ADCs.

Revisiting antibody-drug conjugates and their predictive biomarkers in platinum-resistant ovarian cancer

Until to date, platinum derived drugs are still the backbone of treating ovarian cancer (OC). Most patients treated with platinum-based chemotherapy develop resistance during the course of their management. The treatment of platinum-resistant ovarian cancer (PROC) is challenging. Few therapeutic options are available for patients with this aggressive disease. Besides, there are liminal advances regarding new anticancer drugs as well as validated predictive biomarkers of clinical outcomes in this setting. The enrollment of PROC patients in interventional studies is limited as compared to newly launched clinical trials for platinum-sensitive OC. Enthusiastically, the emergence of antibody-drug conjugates (ADCs) has provided promising findings for further clinical development in PROC. ADCs have the advantage to selectively deliver cytotoxic drugs to cancer cells expressing several of antigens using specific monoclonal antibodies based on the concept of immune bioconjugation. This innovative class of therapeutics showed encouraging early signs of clinical efficacy in PROC particularly mirvetuximab soravtansine that has been successfully introduced into three randomized and controlled phase III studies. In this review, the evidence from clinical trials supporting the development of ADCs targeting folate receptor alpha, sodium-dependent phosphate transporter 2B, dipeptidase 3, mesothelin, mucin 16, and tissue factor using various cytotoxic payloads in PROC is reviewed.

Antibody-Antineoplastic Conjugates in Gynecological Malignancies: Current Status and Future Perspectives

In the last decade, antibody-drug conjugates (ADCs), normally formed by a humanized antibody and a small drug via a chemical cleavable or non-cleavable linker, have emerged as a potential treatment strategy in cancer disease. They allow to get a selective delivery of the chemotherapeutic agents at the tumor level, and, consequently, to improve the antitumor efficacy and, especially to decrease chemotherapy-related toxicity. Currently, nine antibody-drug conjugate-based formulations have been already approved and more than 80 are under clinical trials for the treatment of several tumors, especially breast cancer, lymphomas, and multiple myeloma. To date, no ADCs have been approved for the treatment of gynecological formulations, but many formulations have been developed and have reached the clinical stage, especially for the treatment of ovarian cancer, an aggressive disease with a low five-year survival rate. This manuscript analyzes the ADCs formulations that are under clinical research in the treatment of gynecological carcinomas, specifically ovarian, endometrial, and cervical tumors.

The promising role of antibody drug conjugate in cancer therapy: Combining targeting ability with cytotoxicity effectively

Introduction

Traditional cancer therapy has many disadvantages such as low selectivity and high toxicity of chemotherapy, as well as insufficient efficacy of targeted therapy. To enhance the cytotoxic effect and targeting ability, while reducing the toxicity of antitumor drugs, an antibody drug conjugate (ADC) was developed to deliver small molecular cytotoxic payloads directly to tumor cells by binding to specific antibodies via linkers.

Method

By reviewing published literature and the current progress of ADCs, we aimed to summarize the basic characteristics, clinical progress, and challenges of ADCs to provide a reference for clinical practice and further research.

Results

ADC is a conjugate composed of three fundamental components, including monoclonal antibodies, cytotoxic payloads, and stable linkers. The mechanisms of ADC including the classical internalization pathway, antitumor activity of antibodies, bystander effect, and non‐internalizing mechanism. With the development of new drugs and advances in technology, various ADCs have achieved clinical efficacy. To date, nine ADCs have received US Food and Drug Administration (FDA) approval in the field of hematologic tumors and solid tumors, which have become routine clinical treatments.

Conclusion

ADC has changed traditional treatment patterns for cancer patients, which enable the same treatment for pancreatic cancer patients and promote individualized precision treatment. Further exploration of indications could focus on early‐stage cancer patients and combined therapy settings. Besides, the mechanisms of drug resistance, manufacturing techniques, optimized treatment regimens, and appropriate patient selection remain the major topics.

Advances in the treatment of platinum resistant epithelial ovarian cancer: an update on standard and experimental therapies

Introduction: Platinum-resistant ovarian cancer (PROC) is broadly defined as disease recurrence within 6 months of completing platinum-based chemotherapy, either in the primary or recurrent setting. Although there is significant heterogeneity, PROC is generally associated with poor outcomes and low response rates to standard chemotherapy. There have been novel developments in therapeutics for PROC based on biomarkers and a more nuanced understanding of DNA repair and immunologic pathways.Areas covered: This review provides a summary of standard of care and experimental therapies for patients with PROC. Recent advances in our understanding of the DNA damage response and immunobiology of ovarian cancer have paved the way for single agent and combinatorial strategies involving PARP inhibitors, cell cycle checkpoint inhibitors, and immune checkpoint inhibitors to overcome PARP resistance, capitalize on high replication stress, and promote effective anti-tumor immunity, respectively. Furthermore, novel agents including antibody drug conjugates, bispecific antibodies, and recombinant fusion proteins show promise as experimental treatment options.Expert opinion: Standard and experimental treatment options available to patients with PROC have expanded. Testing for BRCA status, tumor mutational burden, and mismatch repair deficiency is recommended to guide therapy. Clinical trial participation is strongly encouraged with a focus on biomarker-driven trials targeting specific patient populations. Novel approaches such as ADCs, bispecific antibodies, targeting the GAS6/AXL and Notch pathways, and oncolytic virotherapy show considerable promise as emerging therapies.