Spotlight on ideal target antigens and resistance in antibody-drug conjugates: Strategies for competitive advancement

Antibody-drug conjugates (ADCs) represent a novel and promising approach in targeted therapy, uniting the specificity of antibodies that recognize specific antigens with payloads, all connected by the stable linker. These conjugates combine the best targeted and cytotoxic therapies, offering the killing effect of precisely targeting specific antigens and the potent cell-killing power of small molecule drugs. The targeted approach minimizes the off-target toxicities associated with the payloads and broadens the therapeutic window, enhancing the efficacy and safety profile of cancer treatments. Within precision oncology, ADCs have garnered significant attention as a cutting-edge research area and have been approved to treat a range of malignant tumors. Correspondingly, the issue of resistance to ADCs has gradually come to the fore. Any dysfunction in the steps leading to the ADCs' action within tumor cells can lead to the development of resistance. A deeper understanding of resistance mechanisms may be crucial for developing novel ADCs and exploring combination therapy strategies, which could further enhance the clinical efficacy of ADCs in cancer treatment. This review outlines the brief historical development and mechanism of ADCs and discusses the impact of their key components on the activity of ADCs. Furthermore, it provides a detailed account of the application of ADCs with various target antigens in cancer therapy, the categorization of potential resistance mechanisms, and the current state of combination therapies. Looking forward, breakthroughs in overcoming technical barriers, selecting differentiated target antigens, and enhancing resistance management and combination therapy strategies will broaden the therapeutic indications for ADCs. These progresses are anticipated to advance cancer treatment and yield benefits for patients.

Bevacizumab, olaparib, and durvalumab in patients with relapsed ovarian cancer: a phase II clinical trial from the GINECO group

Most patients with advanced ovarian cancer (AOC) ultimately relapse after platinum-based chemotherapy. Combining bevacizumab, olaparib, and durvalumab likely drives synergistic activity. This open-label phase 2 study (NCT04015739) aimed to assess activity and safety of this triple combination in female patients with relapsed high-grade AOC following prior platinum-based therapy. Patients were treated with olaparib (300 mg orally, twice daily), the bevacizumab biosimilar FKB238 (15 mg/kg intravenously, once-every-3-weeks), and durvalumab (1.12 g intravenously, once-every-3-weeks) in nine French centers. The primary endpoint was the non-progression rate at 3 months for platinum-resistant relapse or 6 months for platinum-sensitive relapse per RECIST 1.1 and irRECIST. Secondary endpoints were CA-125 decline with CA-125 ELIMination rate constant K (KELIM-B) per CA-125 longitudinal kinetics over 100 days, progression free survival and overall survival, tumor response, and safety. Non-progression rates were 69.8% (90%CI 55.9%-80.0%) at 3 months for platinum-resistant relapse patients (N = 41), meeting the prespecified endpoint, and 43.8% (90%CI 29.0%-57.4%) at 6 months for platinum-sensitive relapse (N = 33), not meeting the prespecified endpoint. Median progression-free survival was 4.1 months (95%CI 3.5-5.9) and 4.9 months (95%CI 2.9-7.0) respectively. Favorable KELIM-B was associated with better survival. No toxic deaths or major safety signals were observed. Here we show that further investigation of this triple combination may be considered in AOC patients with platinum-resistant relapse.

Mirvetuximab soravtansine in ovarian cancer therapy: expert opinion on pharmacological considerations

ImmunoGen developed mirvetuximab soravtansine as an antibody-drug conjugate comprising of a humanized anti-folate receptor-α (FRα) monoclonal antibody of IgG1k subtype, a cleavable linker, and a cytotoxic payload, DM4. Mirvetuximab soravtansine was granted accelerated approval by the US FDA on November 14, 2022, for the treatment of adult patients with FRα positive, platinum-resistant epithelial ovarian, fallopian tube or primary peritoneal cancer who have received 1-3 prior systemic treatment regimens. The approval of mirvetuximab soravtansine represents a breakthrough for addressing the unmet medical needs of ovarian cancer, especially for up to 80% of patients who relapse and become resistant to platinum-based chemotherapy, resulting in poor prognosis and limited treatment options. However, it is my impression that addressing several pharmacological factors could improve the safety and efficacy of mirvetuximab soravtansine. This article summarizes the current pharmacological profile of mirvetuximab soravtansine and provides an expert opinion on pharmacological strategies for optimizing its safety and efficacy profile for the treatment of platinum-resistant ovarian cancer.

The promise and challenges of combination therapies with antibody-drug conjugates in solid tumors

Antibody-drug conjugates (ADCs) represent an important class of cancer therapies that have revolutionized the treatment paradigm of solid tumors. To date, many ongoing studies of ADC combinations with a variety of anticancer drugs, encompassing chemotherapy, molecularly targeted agents, and immunotherapy, are being rigorously conducted in both preclinical studies and clinical trial settings. Nevertheless, combination therapy does not always guarantee a synergistic or additive effect and may entail overlapping toxicity risks. Therefore, understanding the current status and underlying mechanisms of ADC combination therapy is urgently required. This comprehensive review analyzes existing evidence concerning the additive or synergistic effect of ADCs with other classes of oncology medicines. Here, we discuss the biological mechanisms of different ADC combination therapy strategies, provide prominent examples, and assess their benefits and challenges. Finally, we discuss future opportunities for ADC combination therapy in clinical practice.

The ever-expanding landscape of antibody-drug conjugates (ADCs) in solid tumors: A systematic review

BACKGROUND

The advent of targeted therapies signaled novel avenues for more optimal oncological outcomes. Antibody-drug conjugates (ADCs) have risen as a cornerstone of the ever-expanding targeted therapy era. The purpose of this systematic review is to delineate the rapidly evolving clinical landscape of ADCs for solid tumors.

METHODS

A literature search was performed in Medline, Embase and Cochrane databases for phase II and III clinical trials. Outcomes of interest were the objective response rate, overall survival, progression-free survival and adverse events.

RESULTS

A total of 92 clinical trials (76 phase II and 16 phase III) evaluated the efficacy and safety of ADCs for a plethora of solid tumors. Out of the 30 investigated ADCs, 8 have received approval by regulatory organizations for solid tumors. Currently, 52 phase III clinical trials for ADCs are ongoing.

CONCLUSION

ADCs have shown promising results for several solid tumors and various cancer settings.

Mirvetuximab Soravtansine in Platinum-Resistant Ovarian Cancer

Ovarian cancer is the second leading cause of death from gynecologic malignancies worldwide. Management of platinum-resistant disease is challenging and clinical outcomes with standard chemotherapy are poor. Over the past decades, significant efforts have been made to understand drug resistance and develop strategies to overcome treatment failure. Antibody drug conjugates (ADCs) are a rapidly growing class of oncologic therapeutics, which combine the ability to target tumor-specific antigens with the cytotoxic effects of chemotherapy. Mirvetuximab soravtansine is an ADC comprising an IgG1 monoclonal antibody against the folate receptor alpha (FRα) conjugated to the cytotoxic maytansinoid effector molecule DM4 that has shown promising clinical activity in patients with FR-α-positive ovarian cancer. This review summarizes current evidence of mirvetuximab soravtansine in platinum-resistant ovarian cancer, focusing on clinical activity, toxicity, and future directions.

Mirvetuximab soravtansine for platinum-resistant epithelial ovarian cancer

INTRODUCTION

Mirvetuximab soravtansine (mirvetuximab) is an antibody drug conjugate (ADC) comprised of a humanized folate receptor alpha (FRα)-binding monoclonal antibody attached via a cleavable linker to the cytotoxic maytansinoid molecule, DM4. FRα is expressed in several epithelial cancers, including high grade serous ovarian cancer (HGSOC). Mirvetuximab received accelerated approval by the United States Food and Drug Administration (FDA) in November 2022 based on the results of the SORAYA trial, which tested mirvetuximab for the treatment of patients with recurrent platinum resistant HGSOC with high FRα expression and showed an overall response rate (ORR) of 32.4% and a median duration of response of 6.9 months. Mirvetuximab toxicities included low grade ocular and gastrointestinal toxicities. The National Comprehensive Cancer Network (NCCN) ovarian cancer 2023 guidelines adopted mirvetuximab as 2A, and mirvetuximab combined with bevacizumab as 2B, recommendations.

AREAS COVERED

This manuscript will review the preclinical and clinical development of mirvetuximab, the toxicities associated with mirvetuximab and mitigation strategies, and future applications of mirvetuximab.

EXPERT OPINION

Mirvetuximab represents the first biomarker-directed therapy with an indication specifically for the treatment of PROC. The efficacy and favorable safety profile support further development of mirvetuximab and mirvetuximab combinations in platinum sensitive and newly diagnosed ovarian cancer.

Antibody-drug conjugates: in search of partners of choice

Antibody-drug conjugates (ADCs) have become a credentialled class of anticancer drugs for both solid and hematological malignancies, with regulatory approvals mainly as single agents. Despite extensive preclinical and clinical efforts to develop rational ADC-based combinations, to date only a limited number have demonstrated survival improvements over standard of care. The most appealing partners for ADCs are those that offer additive or synergistic effects on tumor cells or their microenvironment without unacceptable overlapping toxicities. Coadministration with antiangiogenic compounds, HER2-targeting drugs, DNA-damage response agents and immune checkpoint inhibitors (ICIs) represent active forerunners. Through the identification of targets with tumor-specific expression, improved conjugation technologies, and novel linkers and payloads offering superior therapeutic indices, the next generation of ADCs brings optimism to combinatorial approaches.

Advances in antibody-drug conjugates for gynecologic malignancies

PURPOSE OF REVIEW

Antibody-drug conjugates (ADCs) represent a new class of drugs that combine a surface receptor-targeting antibody linked to a cytotoxic molecule delivering the potent cytotoxic payload directly to tumor cells. This review summarizes the current literature demonstrating their use in the treatment of gynecologic malignancies.

RECENT FINDINGS

Tisotumab vedotin is the first U.S. Food and Drug Administration (FDA) approved ADC for the treatment of gynecologic cancers. While in the phase 3 randomized controlled trial in platinum resistant ovarian cancer patients, FORWARD 1, mirvetuximab did not meet its primary endpoint of progression-free survival. But we await more recent data from the two ongoing phase 3 trials of mirvetuximab in recurrent ovarian cancer patients. HER2/neu, Napi2b, mesothelin, and human trophoblast cell-surface marker (Trop-2) overexpression have also been exploited as excellent targets by novel ADCs in multiple tumors including ovarian, endometrial, and cervical cancers.

SUMMARY

Current evidence strongly supports the use of ADCs and ongoing clinical trials will provide further information into the potential of making these drugs part of current standard practice allowing patients to be treated with a higher level of personalized cancer care.

Advancing antibody-drug conjugates in gynecological malignancies: myth or reality?

Antibody-drug conjugates (ADCs) represent a new class of therapeutic agents designed to target specific antigens on tumor cells, combining the specificity of monoclonal antibodies to the cytotoxicity of classic chemotherapy agents. These drugs have been extensively studied both in solid and hematologic malignancies, leading to substantial improvement in the therapeutic landscape for several tumors. Despite no ADC have been yet approved for the treatment of gynecological malignancies, some agents have shown promising results and might have the potential to become part of the standard of care. Among them, mirvetuximab soravtansine has shown activity in platinum-resistant ovarian cancer with high folate-α receptor expression, as a single agent and in combination. Tisotumab vedotin is active in patients with pre-treated cervical cancer, and further investigation is ongoing. The purpose of this review is to summarize the structural and functional characteristics of ADCs and analyze the most recent and promising data regarding the clinical development of ADCs in gynecological malignancies. The available data on the efficacy of the more studied ADCs in ovarian, endometrial, and cervical cancers will be discussed along with toxicities of special interest, the mechanisms of resistance, and future possible drugs combination.

Antibody drug conjugate: the "biological missile" for targeted cancer therapy

Antibody–drug conjugate (ADC) is typically composed of a monoclonal antibody (mAbs) covalently attached to a cytotoxic drug via a chemical linker. It combines both the advantages of highly specific targeting ability and highly potent killing effect to achieve accurate and efficient elimination of cancer cells, which has become one of the hotspots for the research and development of anticancer drugs. Since the first ADC, Mylotarg^® (gemtuzumab ozogamicin), was approved in 2000 by the US Food and Drug Administration (FDA), there have been 14 ADCs received market approval so far worldwide. Moreover, over 100 ADC candidates have been investigated in clinical stages at present. This kind of new anti-cancer drugs, known as “biological missiles”, is leading a new era of targeted cancer therapy. Herein, we conducted a review of the history and general mechanism of action of ADCs, and then briefly discussed the molecular aspects of key components of ADCs and the mechanisms by which these key factors influence the activities of ADCs. Moreover, we also reviewed the approved ADCs and other promising candidates in phase-3 clinical trials and discuss the current challenges and future perspectives for the development of next generations, which provide insights for the research and development of novel cancer therapeutics using ADCs.

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.