Safety and efficacy of antibody-drug conjugates plus immunotherapy in solid tumours: A systematic review and meta-analysis

BACKGROUND

Combining antibody-drug conjugate (ADCs) with immune checkpoint inhibitors (ICIs) is emerging as a promising treatment option to increase efficacy outcomes. However, concerns arise regarding the safety of these combinations, as some toxicities may overlap. Currently, there is still limited information about the safety profiles of this strategy.

METHODS

A systematic review and meta-analysis was conducted to identify clinical trials investigating FDA-approved ADCs in combination with ICI drugs in the metastatic setting across all solid tumors. The primary endpoint of this study was the percentage of adverse events (AEs) of any grade and grade ≥ 3. Secondary endpoints include the percentage of patients with AEs leading to death, treatment discontinuation, proportion of complete responses (CR) and overall response rate (ORR). A parallel search was conducted to quantify the safety profile of ADCs and ICIs in monotherapy. Random effects models were used to estimate pooled outcomes.

RESULTS

Sixteen trials involving 1,133 patients treated with ADC plus ICI met the inclusion criteria with six different ADCs evaluated. Overall, 55.3 % of patients developed grade ≥ 3 AEs, 30.0 % of patients had treatment discontinuation, and 3.0 % experienced AEs leading to death. When compared to trials evaluating ADC or ICI as monotherapy, the combination results in similar rates of the most common AEs. However, it increases the risk of specific toxicities, such as ILD/pneumonitis (15.0 % with T-DXd plus ICI vs. 11.5 % with T-DXd alone). The pooled ORR was 48.8 % (95 %CI 39.4 % - 58.4 %) and the CR rate was 9.0 % (95 %CI 5.5 - 14.5). PD-L1-positive tumors showed numerically better efficacy outcomes.

CONCLUSIONS

This meta-analysis shows that the safety profile of the ADC plus ICI is comparable to that of ADC monotherapy. However, it increases the risk of certain toxicities of special interest, such as ILD/pneumonitis, highlighting the need for careful monitoring.

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 solid tumors: a look into novel targets

Antibody-drug conjugates (ADCs) are a relatively new class of anticancer agents designed to merge the selectivity of monoclonal antibodies with cell killing properties of chemotherapy. They are commonly described as the "Trojan Horses" of therapeutic armamentarium, because of their capability of directly conveying cytotoxic drug (payloads) into the tumor space, thus transforming chemotherapy into a targeted agent. Three novel ADCs have been recently approved, i.e., trastuzumab deruxtecan, sacituzumab govitecan and enfortumab vedotin, respectively, targeting HER2, Trop2 and Nectin4. Thanks to progressive advances in engineering technologies these drugs rely on, the spectrum of diseases sensitive to these drugs as well as their indications are in continuous expansion. Several novel ADCs are under evaluation, exploring new potential targets along with innovative payloads. This review aims at providing a summary of the technology behind these compounds and at presenting the latest ADCs approved in solid tumors, as well as at describing novel targets for ADCs under investigation and new strategies to optimize their efficacy in solid tumors.

Antibody-Drug Conjugates for Cancer Treatment

The concept of exploiting the specific binding properties of monoclonal antibodies as a mechanism for selective delivery of cytotoxic agents to tumor cells is an attractive solution to the challenge of increasing the therapeutic index of cell-killing agents for treating cancer. All three parts of an antibody-drug conjugate (ADC)-the antibody, the cytotoxic payload, and the linker chemistry that joins them together-as well as the biologic properties of the cell-surface target antigen are important in designing an effective anticancer agent. The approval of brentuximab vedotin in 2011 for treating relapsed Hodgkin's lymphoma and systemic anaplastic large cell lymphoma, and the approval of ado-trastuzumab emtansine in 2013 for treating HER2-positive metastatic breast cancer, have sparked vigorous research in the field, with >65 ADCs currently in clinical evaluation. This review highlights the ADCs that are approved for marketing, in pivotal clinical trials, or in at least phase II clinical development for treating both hematologic malignancies and solid tumors.

Is Targeting the Folate Receptor in Ovarian Cancer Coming of Age?

Prognosis for women with epithelial ovarian cancer remains poor. One new molecular target in epithelial ovarian cancer is folate receptor alpha (FRα). This commentary discusses the characteristics that contribute to its attractiveness as a candidate for therapeutic intervention.