Advances in antibody-drug conjugates for gynecologic malignancies

Updates in the Use of Targeted Therapies for Gynecologic Cancers

Targeted therapies have changed the treatment landscape in gynecologic cancer. Studies released over the past year have led to the incorporation of immunotherapy (IO) into the treatment for all patients with endometrial and cervical cancers at some point during their disease course. Poly(ADP-ribose) polymerase (PARP) inhibitors continue to play a role in women with ovarian carcinoma, particularly in homologous repair deficient tumors. Furthermore, the benefit of PARP inhibitors in challenging subgroups continues to be elucidated. Biomarker identification has led to the approval or compendium listing of several antibody-drug conjugates (ADCs). This review will update on IO, ADCs, and PARP inhibition for the treatment of gynecologic cancers.

Ocular toxicities associated with antibody drug conjugates

PURPOSE OF REVIEW

To review the structure, mechanism of action, and pathophysiology of antibody-drug conjugates (ADCs) used to treat gynecological malignancies associated with ocular adverse effects.

RECENT FINDINGS

Recent research shows tisotumab vedotin causes ocular toxicity localized to the conjunctiva, with common adverse effects being conjunctivitis, dry eye, blepharitis, and keratitis. Toxicity is likely due to targeting tissue factor (TF) in the conjunctiva, leading to direct delivery of the cytotoxic payload resulting in apoptosis and bystander killing. Mirvetuximab soravtansine causes blurred vision, keratitis, or dry eye with toxicity often localized in the cornea. Off-target inflammation appears to cause ocular adverse effects, with nonreceptor mediated macropinocytosis by corneal stem cells.

SUMMARY

Collaboration between oncologists and ophthalmologists with adherence to mitigation protocols can decrease the risk of ocular adverse events.

Mirvetuximab soravtansine-gynx: first antibody/antigen-drug conjugate (ADC) in advanced or recurrent ovarian cancer

Mirvetuximab soravtansine-gynx (MIRV) is a conjugate of a folate receptor alpha (FRα)-directed antibody and the maytansinoid microtubule inhibitor, DM4. Accumulating pre-clinical and clinical data supported the safety and anti-tumor activity of MIRV in tumors expressing FRα. In 2017, a phase I expansion study reported the first experience of MIRV in FRα-positive platinum-resistant ovarian cancer with promising results. However, the phase III FORWARD I study failed to demonstrate a significant benefit of MIRV in FRα-positive tumors. On the basis of the data reported from this latter study, MIRV was then explored in the FRα-high population only and using a different folate receptor assay. The phase II SORAYA trial supported the adoption of MIRV in this setting. Hence, the US Food and Drug Administration granted accelerated approval of MIRV for patients with FRα-positive platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer who have received 1-3 prior systemic treatment regimens. Moreover, the results of the MIRASOL trial showed a significant reduction in the risk of tumor progression or death among patients treated with MIRV versus chemotherapy. VENTANA FOLR1 (FOLR-2.1) was approved as a companion diagnostic test to identify FRα patients. MIRV appears to be a significant asset in managing advanced or recurrent ovarian cancer. Further trials are needed to confirm these promising results, even in the neoadjuvant, adjuvant, and maintenance settings.

Fam-Trastuzumab Deruxtecan in HER2/Neu-Expressing Serous Endometrial Cancer

Trastuzumab deruxtecan treatment of 3 patients with HER2/neu-expressing serous endometrial cancer resulted in objective response

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.

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.

Systematic Studies on Anti-Cancer Evaluation of Stilbene and Dibenzo[b,f]oxepine Derivatives

Cancer is one of the most common causes of human death worldwide; thus, numerous therapies, including chemotherapy, have been and are being continuously developed. In cancer cells, an aberrant mitotic spindle-a microtubule-based structure necessary for the equal splitting of genetic material between daughter cells-leads to genetic instability, one of the hallmarks of cancer. Thus, the building block of microtubules, tubulin, which is a heterodimer formed from α- and β-tubulin proteins, is a useful target in anti-cancer research. The surface of tubulin forms several pockets, i.e., sites that can bind factors that affect microtubules' stability. Colchicine pockets accommodate agents that induce microtubule depolymerization and, in contrast to factors that bind to other tubulin pockets, overcome multi-drug resistance. Therefore, colchicine-pocket-binding agents are of interest as anti-cancer drugs. Among the various colchicine-site-binding compounds, stilbenoids and their derivatives have been extensively studied. Herein, we report systematic studies on the antiproliferative activity of selected stilbenes and oxepine derivatives against two cancer cell lines-HCT116 and MCF-7-and two normal cell lines-HEK293 and HDF-A. The results of molecular modeling, antiproliferative activity, and immunofluorescence analyses revealed that compounds 1a, 1c, 1d, 1i, 2i, 2j, and 3h were the most cytotoxic and acted by interacting with tubulin heterodimers, leading to the disruption of the microtubular cytoskeleton.