Phase 1 dose-escalation study of mirvetuximab soravtansine (IMGN853), a folate receptor α-targeting antibody-drug conjugate, in patients with solid tumors

The oncolytic adenovirus TILT-123 with pembrolizumab in platinum resistant or refractory ovarian cancer: the phase 1a PROTA trial

Immune checkpoint inhibitors have demonstrated modest efficacy as a monotherapy in ovarian cancer. Originally developed to improve efficacy of T-cell therapies such as immune checkpoint inhibitors and adoptive cell transfer, TILT-123 (Ad5/3-E2F-D24-hTNFα-IRES-hIL-2) is a serotype chimeric oncolytic adenovirus encoding tumor necrosis factor alpha and interleukin-2. Here we report results from phase 1a of PROTA, a single-arm, multicentre dose escalation trial with TILT-123 and pembrolizumab in female patients with platinum resistant or refractory ovarian cancer (NCT05271318). The primary endpoint was safety. Secondary endpoints included efficacy, tolerability, virus persistence and anti-viral immunity. Patients (n = 15) received intravenous and intraperitoneal and/or intratumoral injections of TILT-123 as well as intravenous pembrolizumab. Treatment was well tolerated, and no dose-limiting toxicities were observed. The most frequent adverse events were fever (40%), fatigue (40%) and nausea (40%). Disease control was achieved in 64% of evaluable patients (9/14). Median progression-free survival and overall survival were 98 and 190 days respectively. Clinical responses were associated with higher serum anti-adenovirus neutralizing antibody titer at baseline and post-treatment. The phase 1b investigating TILT-123, pembrolizumab and PEGylated liposomal doxorubicin in a similar patient population is underway.

Opportunities for predictive proteogenomic biomarkers of drug treatment sensitivity in epithelial ovarian cancer

Genomic analysis has played a significant role in the identification of driver mutations that are linked to disease progression and response to drug treatment in ovarian cancer. A prominent example is the stratification of epithelial ovarian cancer (EOC) patients with homologous recombination deficiency (HRD) characterized by mutations in DNA damage repair genes such as BRCA1/2 for treatment with PARP inhibitors. However, recent studies have shown that some epithelial ovarian tumors respond to PARP inhibitors irrespective of their HRD or BRCA mutation status. An exclusive focus on the genome overlooks the significant insight that can be gained from other biological analytes, including proteins, which carry out cellular functions. Proteogenomics is the integration of genomics, transcriptomics, epigenomics and proteomics data. This review paper provides novel insight into the role of proteogenomics as an analytical approach to identify predictive biomarkers of drug treatment response in epithelial ovarian cancer. Proteogenomic analysis can facilitate the identification of predictive biomarkers of drug treatment response, consequently greatly improving the stratification of patients with EOC for treatment towards a goal of personalized medicine.

Exposure-response relationships of mirvetuximab soravtansine in patients with folate receptor-α-positive ovarian cancer: Justification of therapeutic dose regimen

AIMS

This study aimed to investigate exposure-response (ER) relationships in efficacy and safety for mirvetuximab soravtansine (MIRV) which is a first-in-class antibody-drug conjugate approved for the treatment of folate receptor-α-positive platinum-resistant ovarian cancer.

METHODS

MIRV was characterized in 4 clinical studies. Exposure metrics for MIRV, its payload and a metabolite were derived from a population pharmacokinetic model. Efficacy was analysed in MIRV-treated patients (n = 215) in a recent confirmatory, randomized, chemotherapy-controlled MIRASOL trial and safety was evaluated in patients pooled across all 4 clinical studies (n = 757).

RESULTS

In the MIRASOL trial (NCT04209855), MIRV demonstrated significant benefit over chemotherapy in progression-free survival (PFS), objective response rate (ORR) and overall survival (OS). The most common adverse events (AEs) included ocular disorders, peripheral neuropathy and pneumonitis. For PFS, ORR and OS, the trough concentration of MIRV was the predictor consistently found in ER models for efficacy. In contrast, for ocular AEs (as well as the time to onset of ocular AEs) and peripheral neuropathy, the area under the concentration-time curve (AUC) of MIRV was identified as the exposure metric in ER models for safety. No exposure parameters were found to correlate with pneumonitis. Covariates in all models did not show clinically meaningful impact on efficacy or safety. Logistic regression models for ORR and ocular AEs based on AUC of MIRV were used to justify the clinical dose regimen approved for MIRV.

CONCLUSION

The trough concentration of MIRV correlated with efficacy whereas the AUC of MIRV was associated with major AEs. The ER relationships supported the selected therapeutic dose regimen.

Practical clinical management of ocular adverse events related to Antibody-Drug Conjugates in gynaecological malignancies

BACKGROUND

The advent of Antibody-Drug Conjugates (ADC) represents a significant advancement in targeted therapy for gynaecological malignancies. However, the ocular toxicities associated with ADCs, particularly Tisotumab Vedotin (TV) and Mirvetuximab Soravtansine (MIRV) necessitate effective mitigation in order to optimise patient care.

METHODS

This review synthesises findings from clinical trials to delineate the spectrum of ocular adverse events induced by ADCs. The analysis focuses on the incidence, onset, severity and reversibility of adverse events. It examines the underlying mechanisms of toxicity and provides management strategies based on study protocols.

RESULTS

Adverse events mainly impact the anterior ocular segment, resulting in conjunctivitis and keratopathy. They affect up to 56 % of patients treated with MIRV and 50 to 60 % of those receiving TV. Symptoms like blurred vision, dryness and pain hinder the patient's quality of life. Events are CTCAE grade 3 or higher in less than 10 % of cases. The median time to onset is 1.3 months. However, ocular toxicity may appear up to 10 months after treatment initiation, indicating a need for prolonged vigilance. Primary prophylaxis calls for local corticotherapy, lubricants and in some cases, vasoconstrictors. Despite the potential for severity, most cases are reversible with local treatment and transient dose reduction and/or delay. Close monitoring is crucial for early detection and subsequent management.

CONCLUSIONS

Clinicians ought to be cognizant of the potential ocular toxicity of ADCs. Proactive prophylaxis, patient education and a multidisciplinary approach involving ophthalmologists are paramount to minimising the impact of these AEs. Further research is essential to measure the real outcome of preventive strategies and balance their benefits with potential short and long-term risks.

Safety and tolerability of mirvetuximab soravtansine monotherapy for folate receptor alpha-expressing recurrent ovarian cancer: An integrated safety summary

OBJECTIVE

Mirvetuximab soravtansine-gynx (MIRV) is a novel antibody-drug conjugate targeting folate receptor alpha (FRα), which is overexpressed in epithelial ovarian cancer (EOC), with limited expression on normal tissues. This integrated safety summary sought to characterize the safety profile of MIRV monotherapy in participants with FRα-expressing recurrent EOC.

METHODS

Safety data were retrospectively analyzed from 4 clinical studies (phase 1 trial [NCT01609556], phase 3 FORWARD I [NCT02631876], phase 2 SORAYA [NCT04296890], phase 3 MIRASOL [NCT04209855]) that evaluated participants with FRα-expressing recurrent EOC who received ≥1 dose of MIRV 6 mg/kg adjusted ideal body weight every 3 weeks.

RESULTS

In this analysis of 682 participants, 94 % had platinum-resistant ovarian cancer (PROC). Blurred vision (43 %), nausea (41 %), diarrhea (39 %), and fatigue (35 %) were the most common treatment-emergent adverse events (TEAEs) and were primarily grade 1-2 in severity. Grade ≥ 3 TEAEs occurred in 48 % of participants, with the most common being keratopathy and blurred vision (5 % each). Most TEAEs were managed with supportive care and dose modifications, and only 12 % of participants experienced a TEAE leading to discontinuation (1 % due to ocular events). No corneal ulcerations or perforations have been reported. Median time to onset of blurred vision and keratopathy was 5.9 and 6.7 weeks, respectively. Most blurred vision events and keratopathy events resolved completely (71 % and 66 %, respectively) or partially (15 % and 14 %, respectively).

CONCLUSIONS

As demonstrated among 682 participants, the safety profile of MIRV is well tolerated and consists primarily of low-grade gastrointestinal, fatigue, headache, peripheral neuropathy, and resolvable ocular adverse events.

Review of dose justifications for antibody-drug conjugate approvals from clinical pharmacology perspective: A focus on exposure-response analyses

Antibody-drug conjugates (ADCs) are revolutionizing cancer treatment by specific targeting of the cancer cells thereby improving the therapeutic window of the drugs. Nevertheless, they are not free from unwanted toxicities mainly resulting from non-specific targeting and release of the payload. Therefore, the dosing regimen must be optimized through integrated analysis of the risk-benefit profile, to maximize the therapeutic potential. Exposure-response (E-R) analysis is one of the most widely used tools for risk-benefit assessment and it plays a pivotal role in dose optimization of ADCs. However, compared to conventional E-R analysis, ADCs pose unique challenges since they feature properties of both small molecules and antibodies. In this article, we review the E-R analyses that have formed the key basis of dose justification for each of the 12 ADCs approved in the USA. We discuss the multiple analytes and exposure metrics that can be utilized for such analysis and their relevance for safety and efficacy of the treatment. For the endpoints used for the E-R analysis, we were able to uncover commonalities across different ADCs for both safety and efficacy. Additionally, we discuss dose optimization strategies for ADCs which are now a critical component in clinical development of oncology drugs.

Dehydrated amniotic membrane patch for the treatment of an ocular event secondary to mirvetuximab soravtansine-gynx (MIRV) therapy

•Mirvetuximab soravtansine (MIRV) is used in the treatment of FRα positive, platinum-resistant epithelial ovarian cancer.•MIRV is associated with ocular events, leading to dose delays, dose reductions, and discontinuations of chemotherapy.•Mitigation strategies to prevent treatment disruption have historically relied on corticosteroid and lubricating drops.•Dehydrated amniotic membrane patch to treat MIRV related ocular events is a novel therapeutic option.

Antibody-Drug Conjugates: A Start of a New Era in Gynecological Cancers

Antibody-drug conjugates (ADCs) are a new class of therapeutic agents designed to target specific antigens on tumor cells, combining the specificity of monoclonal antibodies with the cytotoxicity of chemotherapy agents. ADCs have been available for over a decade, but in gynecological cancers, these agents are relatively new with great promise ahead. More than 80% of ongoing trials in gynecological cancers are evaluating ADCs' safety and efficacy, of which 40% are early-phase trials. Around twenty ADCs are currently under investigation, either alone or in combination with chemotherapies or immune checkpoint inhibitors. Among them, mirvetuximab soravtansine has been recently approved by the Food and Drug Administration (FDA) in platinum-resistant ovarian cancer with high folate-α receptor expression, as a single agent or in combination. Tisotumab vedotin and trastuzumab deruxtecan are also now approved by the FDA in patients with pre-treated cervical and uterine cancers and further investigation is ongoing. Overall, the toxicity profiles of ADCs are acceptable. Ocular toxicity is one of the specific side effects of some ADCs, but most of the cases are manageable with the use of prophylactic steroids and dose adjustments. This review aims to provide an overview of the fundamental and operational features of ADCs and examine the latest and most promising data, with a particular focus on the Canadian viewpoint.

Folate Receptor Alpha-A Secret Weapon in Ovarian Cancer Treatment?

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy worldwide. Due to its nonspecific symptoms and unreliable screening tools, EOC is not diagnosed at an early stage in most cases. Unfortunately, despite achieving initial remission after debulking surgery and platinum-based chemotherapy, most patients experience the recurrence of the disease. The limited therapy approaches have encouraged scientists to search for new detection and therapeutic strategies. In this review, we discuss the role of folate receptor alpha (FRα) in EOC development and its potential application as a biomarker and molecular target in designing new EOC screening and treatment methods. We summarize the mechanisms of the action of various therapeutic strategies based on FRα, including MABs (monoclonal antibodies), ADCs (antibody-drug conjugates), FDCs (folate-drug conjugates), SMDCs (small molecule-drug conjugates), vaccines, and CAR-T (chimeric antigen receptor T) cells, and present the most significant clinical trials of some FRα-based drugs. Furthermore, we discuss the pros and cons of different FR-based therapies, highlighting mirvetuximab soravtansine (MIRV) as the currently most promising EOC-targeting drug.

The clinical landscape of antibody-drug conjugates in endometrial cancer

Clinical outcomes remain challenging in advanced or recurrent endometrial cancer due to tumor heterogeneity and therapy resistance. Antibody-drug conjugates are a novel class of cancer therapeutics, representing a promising treatment option for endometrial cancer. Antibody-drug conjugates consist of a high-affinity antibody linked to a cytotoxic payload through a stable linker. After binding to specific antigens on tumor cells, the drug is internalized, and the payload is released. In addition, the free intracellular drug may be released outside the target cell through a 'bystander effect' and kill neighboring cells, which is crucial in treating malignancies characterized by heterogeneous biomarker expression like endometrial cancer.This article aims to provide a comprehensive overview of the current clinical landscape of antibody-drug conjugates in the treatment of endometrial cancer. We conducted a thorough analysis of recent clinical trials focusing on efficacy, safety profiles, and the mechanisms by which antibody-drug conjugates target endometrial cancer. We focused particularly on the most promising antibody-drug conjugate targets in endometrial cancer under clinical investigation, such as human epidermal growth factor receptor 2 (HER2), folate receptor alpha (FRα), trophoblast cell-surface antigen-2 (TROP2), and B7-H4. We also briefly comment on the challenges, including the emergence of resistance mechanisms, and future development directions (especially agents targeting multiple antigens, combinatorial strategies, and sequential use of agents targeting the same antigen but using different payloads) in antibody-drug conjugate therapy for endometrial cancer.

Assessment of mirvetuximab soravtansine immunogenicity in patients with folate receptor alpha-positive ovarian cancer

Aim: The aim of this research was to evaluate the immunogenicity of mirvetuximab soravtansine (MIRV), an antibody-drug conjugate in patients with folate receptor alpha-positive ovarian cancer across four clinical studies.Materials & methods: An assay was developed and validated for the detection of antidrug antibodies (ADAs) against MIRV. A cell-based method was also developed and validated for the detection of neutralizing anti-MIRV antibodies (NAbs). Both ADAs and NAbs were assessed across four clinical studies in 734 patients.Results: Across studies, MIRV demonstrated low immunogenicity with 7.8% of patients with treatment-emergent ADAs, 7.2% with treatment-unaffected ADAs, and 0.5% with treatment-enhanced ADAs. MIRV trough concentrations were comparable in ADA-negative and ADA-positive individuals. Limited data suggest that MIRV ADAs may be associated with decreased efficacy. Due to the very limited number of NAb-positive individuals, no conclusions could be drawn on the effect of NAb on efficacy.Conclusion: Both the validation tests and the data from the MIRV clinical studies demonstrated that these assays were suitable and reliable for the detection of MIRV ADAs and NAbs. These validated assays will continue to be used to monitor MIRV immunogenicity in future clinical trials.

High-Grade Endometrial Cancer: Molecular Subtypes, Current Challenges, and Treatment Options

Although many recent advancements have been made in women's health, perhaps one of the most neglected areas of research is the diagnosis and treatment of high-grade endometrial cancer (EnCa). The molecular classification of EnCa in concert with histology was a major step forward. The integration of profiling for mismatch repair deficiency and Human Epidermal Growth Factor 2 (HER2) overexpression, can further inform treatment options, especially for drug resistant recurrent disease. Recent early phase trials suggest that regardless of subtype, combination therapy with agents that have distinct mechanisms of action is a fruitful approach to the treatment of high-grade EnCa. Unfortunately, although the importance of diagnosis and treatment of high-grade EnCa is well recognized, it is understudied compared to other gynecologic and breast cancers. There remains a tremendous need to couple molecular profiling and biomarker development with promising treatment options to inform new treatment strategies with higher efficacy and safety for all who suffer from high-grade recurrent EnCa.

Emerging role of mucins in antibody drug conjugates for ovarian cancer therapy

Ovarian cancer stands as the deadliest gynecologic malignancy, responsible for nearly 65% of all gynecologic cancer-related deaths. The challenges in early detection and diagnosis, coupled with the widespread intraperitoneal spread of cancer cells and resistance to chemotherapy, contribute significantly to the high mortality rate of this disease. Due to the absence of specific symptoms and the lack of effective screening methods, most ovarian cancer cases are diagnosed at advanced stages. While chemotherapy is a common treatment, it often leads to tumor recurrence, necessitating further interventions. In recent years, antibody-drug conjugates (ADCs) have emerged as a valuable tool in targeted cancer therapy. These complex biotherapeutics combine an antibody that specifically targets tumor specific/associated antigen(s) with a high potency anti-cancer drug through a linker, offering a promising approach for ovarian cancer treatment. The identification of molecular targets in various human tumors has paved the way for the development of targeted therapies, with ADCs being at the forefront of this innovation. By delivering cytotoxic agents directly to tumors and metastatic lesions, ADCs show potential in managing chemo-resistant ovarian cancers. Mucins such as MUC16, MUC13, and MUC1 have shown significantly higher expression in ovarian tumors as compared to normal and/or benign samples, thus have become promising targets for ADC generation. While traditional markers are limited by their elevated levels in non-cancerous conditions, mucins offer a new possibility for targeted treatment in ovarian cancer. This review comprehensively described the potential of mucins for the generation of ADC therapy, highlighting their importance in the quest to improve the outcome of ovarian cancer patients.

Maintenance with mirvetuximab soravtansine plus bevacizumab vs bevacizumab in FRα-high platinum-sensitive ovarian cancer

At first recurrence, platinum-sensitive ovarian cancer (PSOC) is frequently treated with platinum-based chemotherapy doublets plus bevacizumab, then single-agent bevacizumab. Most patients' disease progresses within a year after chemotherapy, emphasizing the need for novel strategies. Mirvetuximab soravtansine-gynx (MIRV), an antibody-drug conjugate, comprises a folate receptor alpha (FRα)-binding antibody and tubulin-targeting payload (maytansinoid DM4). In FRα-high PSOC, MIRV plus bevacizumab previously showed promising efficacy (objective response rate, 69% [95% CI: 41-89]; median progression-free survival, 13.3 months [95% CI: 8.3-18.3]; median duration of response, 12.9 months [95% CI: 6.5-15.7]) and safety. The Phase III randomized GLORIOSA trial will evaluate MIRV plus bevacizumab vs. bevacizumab alone as maintenance therapy in patients with FRα-high PSOC who did not have disease progression following second-line platinum-based doublet chemotherapy plus bevacizumab.Clinical Trial Registration: ClinicalTrials.gov ID: NCT05445778; GOG.org ID: GOG-3078; ENGOT.ESGO.org ID: ENGOT-ov76.

Unsolved Issues in the Integrated Histo-Molecular Classification of Endometrial Carcinoma and Therapeutic Implications

Endometrial carcinoma (EC) is the most frequent gynecological cancer, with an increasing incidence and mortality in recent times. The last decade has represented a true revolution with the development of the integrated histo-molecular classification of EC, which allows for the stratification of patients with morphologically indistinguishable disease into groups with different prognoses. Particularly, the POLE-mutated subgroup exhibits outstanding survival. Nevertheless, the indiscriminate application of molecular classification appears premature. Its prognostic significance has been proven mainly in endometrioid EC, the most common histotype, but it has yet to be convincingly confirmed in the other minor histotypes, which indeed account for a relevant proportion of EC mortality. Moreover, its daily use both requires a mindful pathologist who is able to correctly evaluate and unambiguously report immunohistochemical staining used as a surrogated diagnostic tool and is hampered by the unavailability of POLE mutation analysis. Further molecular characterization of ECs is needed to allow for the identification of better-tailored therapies in different settings, as well as the safe avoidance of surgery for fertility preservation. Hopefully, the numerous ongoing clinical trials in the adjuvant and metastatic settings of EC will likely produce evidence to refine the histo-molecular classification and therapeutic guidelines. Our review aims to retrace the origin and evolution of the molecular classification for EC, reveal its strengths and limitations, show clinical relevance, and uncover the desired future developments.

New hopes and promises in the treatment of ovarian cancer focusing on targeted treatment-a narrative review

Unfortunately, ovarian cancer is still diagnosed most often only in an advanced stage and is also the most lethal gynecological cancer. Another problem is the fact that treated patients have a high risk of disease recurrence. Moreover, ovarian cancer is very diverse in terms of molecular, histological features and mutations. Many patients may also develop platinum resistance, resulting in poor response to subsequent lines of treatment. To improve the prognosis of patients with ovarian cancer, it is expected to make better existing and implement new, promising treatment methods. Targeted therapies seem very promising. Currently, bevacizumab - a VEGF inhibitor and therapy with olaparib - a polyADP-ribose polymerase inhibitor are approved. Other methods worth considering in the future include: folate receptor α, immune checkpoints or other immunotherapy methods. To improve the treatment of ovarian cancer, it is also important to ameliorate the determination of molecular features to describe and understand which group of patients will benefit most from a given treatment method. This is important because a larger group of patients treated for ovarian cancer can have a greater chance of surviving longer without recurrence.

Unlocking the Potential: Biomarkers of Response to Antibody-Drug Conjugates

Antibody-drug conjugates (ADCs) have reshaped the cancer treatment landscape across a variety of different tumor types. ADCs' peculiar pharmacologic design combines the cytotoxic properties of chemotherapeutic agents with the selectivity of targeted therapies. At present, the approval of many ADCs used in clinical practice has not always been biomarker-driven. Indeed, predicting ADCs' activity and toxicity through the demonstration of specific biomarkers is still a great unmet need, and the identification of patients who can derive significant benefit from treatment with ADCs may often be uncertain. With the lack of robust predictive biomarkers to anticipate primary, intrinsic resistance to ADCs and no consolidated biomarkers to aid in the early identification of treatment resistance (ie, acquired resistance), the determination of precise biologic mechanisms of ADC activity and safety becomes priority in the quest for better patient-centric outcomes. Of great relevance, whether the target antigen expression is a determinant of ADCs' primary activity is still to be clarified, and available data remain quite controversial. Antigen expression assessment is typically performed on tissue biopsy, hence only providing information on a specific tumor site, therefore unable to capture heterogeneous patterns of tumor antigen expression. Quantifying the expression of the target antigen across all tumor sites would help better understand tumor heterogeneity, whereas molecularly characterizing tumor-intrinsic features over time might provide information on resistance mechanisms. In addition, toxicity can represent a critical concern, since most ADCs have a safety profile that resembles that of chemotherapies, with often unique adverse events requiring special management, possibly because of the differential in pharmacokinetics between the small-molecule agent versus payload of a similar class (eg, deruxtecan conjugate-related interstitial lung disease). As such, the identification of robust predictive biomarkers of safety and activity of ADCs has the potential to improve patient selection and enrich the population of patients most likely to derive a substantial clinical benefit, especially in those disease settings where different ADCs happen to be approved in competing clinical indications, with undefined biomarkers to make precise decision making and unclear data on how to sequence ADCs. At this point, the identification of clinically actionable biomarkers in the space of ADCs remains a top research priority.

Biomarkers for Antibody-Drug Conjugates in Solid Tumors

The clinical development and then the progressive entry in clinical practice of antibody-drug conjugates (ADC) have marked a transformative advancement in the overall cancer treatment. ADCs have been extensively tested for a large number of tumors, reporting heterogeneous clinical efficacy and safety results. In some diseases, the advent of ADCs has yielded significant changes in the prognostic trajectory, portending an improvement of the survival and/or quality of life. ADCs are targeted agents, capable of delivering highly cytotoxic payloads selectively to antigen-expressing cancer cells. As such, they have been intended as perfect "bullets" to enable the promise of precision medicine, toward high-efficacy and limited-toxicity treatment options. However, only some approved ADCs are intended for the use in biomarker-selected patient populations, restricting potentially the opportunity to be more precise. Yet, key characteristics of modern ADCs might allow the activity of ADCs in tumors with heterogeneous or low expression of cancer antigens, resulting in a clinical activity that could sublimate the classic paradigm of a drug-to-target perfect match. In our review, we portrayed the current landscape of approved ADCs, reporting data of activity as related to the expression of the cancer antigens, and elucidating possible determinants of the safety and efficacy, including when used in a therapeutic sequence.

The evolving landscape of antibody-drug conjugates in ovarian cancer: new drugs for a new era

PURPOSE OF REVIEW

This review addresses the emerging role of antibody-drug conjugates (ADCs) in the treatment of ovarian cancer, a field marked by a high need for more effective and targeted therapies. Given the recent advancements in ADC technology and the ongoing challenges in treating ovarian cancer, particularly in late-stage and recurrent cases, this review is both timely and relevant. It synthesizes current research findings and clinical trial data, highlighting the potential of ADCs to revolutionize ovarian cancer treatment.

RECENT FINDINGS

The review covers key themes including the mechanism of action of ADCs, their specificity in targeting ovarian cancer cells, recent clinical trial outcomes, advancements in ADC design for improved efficacy and reduced toxicity, and strategies to overcome drug resistance in ovarian cancer. It also addresses the heterogeneity of ovarian cancer and the implications for personalized ADC therapies.

SUMMARY

The review underscores the potential of ADCs to significantly impact clinical practice, offering a more effective and personalized treatment approach for ovarian cancer patients. The review suggests a paradigm shift in the treatment of this malignancy, emphasizing the need for further research and development in this area.

Novel Molecular Targets in Endometrial Cancer: Mechanisms and Perspectives for Therapy

Endometrial cancer (EC) has a high epidemiological impact with incidence and mortality rising worldwide. In recent years, the integration of the pathologic and molecular classification has provided relevant information to understand the heterogeneity in the biology of EC, which led to the evolution in the management of patients. Currently, therapeutic breakthroughs have been made in advanced EC to improve oncologic outcomes, with efforts to include patient reported outcomes. Precision and personalized medicine are under way in EC exploring different combination approaches to target cross-talk pathways, cancer cell microenvironment, and metabolic vulnerabilities and improve drug delivery. Yet, collaborative efforts are needed to face the challenges in practice by refining patient selection, ideal biomarker identification, and de-escalation of therapies according to emerging molecular and genomic features of EC.

Population pharmacokinetics of mirvetuximab soravtansine in patients with folate receptor-α positive ovarian cancer: The antibody-drug conjugate, payload and metabolite

AIMS

Mirvetuximab soravtansine is a first-in-class antibody-drug conjugate recently approved for the treatment of folate receptor-α positive ovarian cancer. The aim of this study was to develop a population pharmacokinetic model to describe the concentration-time profiles of mirvetuximab soravtansine, the payload (DM4) and a metabolite (S-methyl-DM4).

METHODS

Mirvetuximab soravtansine was administered intravenously from 0.15 to 7 mg/kg to 543 patients with predominantly platinum-resistant ovarian cancer in 3 clinical studies, and the plasma drug concentrations were analysed using a nonlinear mixed-effects modelling approach. Stepwise covariate modelling was performed to identify covariates.

RESULTS

We developed a semi-mechanistic population pharmacokinetic model that included linear and nonlinear routes for the elimination of mirvetuximab soravtansine and a target compartment for the formation and disposition of the payload and metabolite in tumour cells. The clearance and volume of the central compartment were 0.0153 L/h and 2.63 L for mirvetuximab soravtansine, 8.83 L/h and 3.67 L for DM4, and 2.04 L/h and 6.3 L for S-methyl-DM4, respectively. Body weight, serum albumin and age were identified as statistically significant covariates. Exposures in patients with renal or hepatic impairment and who used concomitant cytochrome P450 (CYP) 3A4 inhibitors were estimated.

CONCLUSION

There is no need for dose adjustment due to covariate effects for mirvetuximab soravtansine administered at the recommended dose of 6 mg/kg based on adjusted ideal body weight. Dose adjustment is not required for patients with mild or moderate renal impairment, mild hepatic impairment, or when concomitant weak and moderate CYP3A4 inhibitors are used.

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.

Fixed Versus Body-Sized-Based Dosing of Monoclonal Antibodies

Monoclonal antibody products are an increasing portion of novel drug approvals. The labeling of initial drug approvals frequently involves body-size-based rather than fixed-dose administration regimens for adults without clear rationale for doing so. This presents challenges when prescribing these products for patients with extremes of body habitus who constitute a small portion of enrollment in pre-approval investigations. Fixed-dose regimens allow for standardized preparation with the potential to reduce the risk of calculation errors, drug waste, and make home administration more practical. Fixed-dose rather than body-size-based monoclonal antibody regimens should serve as the initial approach in early phase 1 clinical trials.

Antibody-Drug Conjugates in Gynecologic Cancers

OPINION STATEMENT

Antibody-drug conjugates (ADCs) are a novel class of targeted cancer therapies with the ability to selectively deliver a cytotoxic drug to a tumor cell using a monoclonal antibody linked to a cytotoxic payload. The technology of ADCs allows for tumor-specificity, improved efficacy, and decreased toxicity compared to standard chemotherapy. Common toxicities associated with ADC use include ocular, pulmonary, hematologic, and neurologic toxicities. Several ADCs have been approved by the United States Food and Drug Administration (FDA) for the management of patients with recurrent or metastatic gynecologic cancers, a population with poor outcomes and limited effective treatment options. The first FDA-approved ADC for recurrent or metastatic cervical cancer was tisotumab vedotin, a tissue factor-targeting agent, after demonstrating response in the innovaTV 204 trial. Mirvetuximab soravtansine targets folate receptor alpha and is approved for use in patients with folate receptor alpha-positive, platinum-resistant, epithelial ovarian cancer based on results from the SORAYA trial. While there are no FDA-approved ADCs for the treatment of uterine cancer, trastuzumab deruxtecan, an anti-human epidermal growth factor receptor 2 (HER2) agent, is actively being investigated. In this review, we will describe the structure and mechanism of action of ADCs, discuss their toxicity profiles, review ADCs both approved and under investigation for the management of gynecologic cancers, and discuss mechanisms of ADC resistance.

Recent advances in small-molecule fluorescent probes with the function of targeting cancer receptors

Cancer is "the sword of Damocles" that threatens human life and health. Therefore, the diagnosis and treatment of cancer have been receiving much attention. Many overexpressed receptors on the surface of cancer cells provide us with an effective way to specifically identify the cancer cells, and receptor targeting strategies are becoming one of the hot ideas to enhance the ability of fluorescent probes to target tumors. Fluorescent probes connected to ligands are targeted at cancer cell surfaces through receptor-mediated endocytosis. Receptor-targeting probes can image and track cancer cells, determine tumor boundaries, monitor deep lesions, and play a role in clinical medicine, such as fluorescent imaging-guided surgery. In this review, based on the perspective of small molecule fluorescent probes, we reviewed the design ideas, photophysical properties, and applications of receptor-targeting probes for detecting biomarkers in imaging and tracing cancer cells and prospected the future developmental direction of such probes. We hope that this review will provide more ideas for the design and development of active targeting probes for receptors and lead to more applications in the medical field.

Adverse events of antibody-drug conjugates on the ocular surface in cancer therapy

Antibody-drug conjugates consist of a monoclonal antibody attached to a cytotoxic therapeutic molecule by a connector. This association allows a highly specific therapy, which increases their effectiveness and decreases their potential toxicity. This new therapy emerged approximately 20 years ago; since then, numerous combinations have appeared in the field of treatment-related neoplasms as an alternative for patients who do not achieve good results with conventional treatment options. Adverse effects of these drugs on the ocular surface are frequent and varied. Their prevalence ranges from 20 to 90% depending on the drug and administration condition, probably due to multiple receptor-mediated factors or mechanisms not mediated by specific receptors, such as macropinocytosis. These adverse events can greatly limit patients' comfort; thus, the objectives of this article were, in the first place, to compile the information currently available on different types of adverse effects of antibody-drug conjugates on the ocular surface, including pathophysiology, prevalence, and treatment, and in second place, to contribute to the correct identification and management of these events, which will result in a lower rate of cessation of treatment, which is necessary for the survival of candidate patients.

FDA Approval Summary: Mirvetuximab Soravtansine-Gynx for FRα-Positive, Platinum-Resistant Ovarian Cancer

On November 14, 2022, the FDA granted accelerated approval to mirvetuximab soravtansine-gynx for treatment of adult patients with folate receptor-α (FRα)-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer who have received one to three prior systemic therapies. The VENTANA FOLR1 (FOLR-2.1) RxDx Assay was approved as a companion diagnostic device to select patients for this indication. Approval was based on Study 0417 (SORAYA, NCT04296890), a single-arm, multicenter trial. In 104 patients with measurable disease who received mirvetuximab soravtansine-gynx, the overall response rate was 31.7% [95% confidence interval (CI), 22.9-41.6] with a median duration of response of 6.9 months (95% CI, 5.6-9.7). Ocular toxicity was included as a Boxed Warning in the U.S. Prescribing Information (USPI) to alert providers of the risks of developing severe ocular toxicity including vision impairment and corneal disorders. Pneumonitis and peripheral neuropathy were additional important safety risks included as Warnings and Precautions in the USPI. This is the first approval of a targeted therapy for FRα-positive, platinum-resistant ovarian cancer and the first antibody-drug conjugate approved for ovarian cancer. This article summarizes the favorable benefit-risk assessment leading to FDA's approval of mirvetuximab soravtansine-gynx.

Therapeutic strategies targeting folate receptor α for ovarian cancer

Epithelial ovarian cancer (EOC) is the deadliest gynecological cancer, and presents a major clinical challenge due to limited treatment options. Folate receptor alpha (FRα), encoded by the FOLR1 gene, is an attractive therapeutically target due to its prevalent and high expression in EOC cells. Recent basic and translational studies have explored several modalities, such as antibody-drug conjugate (ADC), monoclonal antibodies, small molecules, and folate-drug conjugate, to exploit FRα for EOC treatment. In this review, we summarize the function of FRα, and clinical efficacies of various FRα-based therapeutics. We highlight mirvetuximab soravtansine (MIRV), or Elahere (ImmunoGen), the first FRα-targeting ADC approved by the FDA to treat platinum-resistant ovarian cancer. We discuss potential mechanisms and management of ocular adverse events associated with MIRV administration.

Tusamitamab Ravtansine in Patients with Advanced Solid Tumors: Phase I Study of Safety, Pharmacokinetics, and Antitumor Activity Using Alternative Dosing Regimens

Purpose

Tusamitamab ravtansine is an antibody-drug conjugate that targets carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) and delivers a cytotoxic maytansinoid payload. In a phase I dose-escalation study, the maximum tolerated dose (MTD) was 100 mg/m2 every 2 weeks (Q2W). Here we report results for two alternative schedules.

Experimental Design

Adults ages ≥18 years (range, 34-73) with locally advanced/metastatic solid tumors (N = 43; colon/rectum, 29; stomach, 7; pancreas, 4; other, 3) expressing/likely to express CEACAM5 received intravenous tusamitamab ravtansine 120-170 mg/m2 [loading dose (LD)], then 100 mg/m2 Q2W (Q2W-LD, n = 28), or 120-190 mg/m2 fixed dose [every 3 weeks (Q3W), n = 15]. The primary endpoint was dose-limiting toxicities (DLTs) during cycles 1-2 (Q2W-LD) and cycle 1 (Q3W).

Results

Reversible DLTs were observed in 2 of 9 patients (grade 2 keratopathy; grade 2 keratitis) with 170 mg/m2 in Q2W-LD and in 2 of 3 patients (grade 2 keratopathy; grade 3 transaminase elevation) with 190 mg/m2 in Q3W. Nineteen (67.9%) patients in Q2W-LD and 13 (86.7%) patients in Q3W experienced treatment-related adverse events (AE); 3 of 43 patients discontinued treatment because of AEs. The most common AEs were asthenia, gastrointestinal complaints, keratopathy, keratitis, and peripheral sensory neuropathy. In this small, heavily pretreated population, no confirmed responses were observed; however, stable disease occurred in 35.7% of patients in Q2W-LD and 40.0% of patients in Q3W.

Conclusions

Tusamitamab ravtansine had a favorable safety profile with both alternative administration schedules; MTDs were 170 mg/m2 (LD) followed by 100 mg/m2 Q2W, and 170 mg/m2 Q3W as a fixed dose. (NCT02187848).

Significance

The collective results of this phase I dose-escalation study will inform further studies of tusamitamab ravtansine in patients with solid tumors with CEACAM5 expression, including patients with non-small cell lung cancer.

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.

Evaluation of Folate-Functionalized Nanoparticle Drug Delivery Systems-Effectiveness and Concerns

Targeting folate receptors is a potential solution to low tumor selectivity concerning conventional chemotherapeutics. Apart from antibody-drug conjugates, folate-functionalized nanoparticle drug delivery systems are interesting to be explored due to many advantages, yet currently, none seems to enter the clinical trials. Multiple in vitro evidence is available to support its efficacy compared to the non-targeting carrier and free drug formulation. Additionally, several studies pointed out factors affecting its effectiveness, including surface properties and endosomal trapping. However, in vivo biodistribution studies revealed issues that may arise from folate receptor targeting, including rapid liver uptake, subsequently reducing the nanoparticles' tumor uptake. This issue may be due to the folate receptor β expressed by the activated macrophages in the liver; route of administration and tumor location might also influence the targeting effectiveness. Moreover, it is perplexing to generalize nanoparticles reported from various publications, primarily due to the different formulations, lack of characterization, and experimental settings, making it harder to determine the accurate factor influencing targeting effectiveness.

Ocular toxicities associated with antibody drug conjugates and immunotherapy in oncology: clinical presentation, pathogenesis, and management strategies

INTRODUCTION

The development of molecularly targeted anticancer therapies and immunotherapy continues to revolutionize the treatment of cancer. FDA accelerated approvals of novel targeted therapies allowed for introduction of these agents into the clinic at a rapid rate. On-and off-target ocular toxicities are prevalent treatment-related adverse events of newer therapies including antibody drug conjugates (ADCs) and immunotherapy. Ocular toxicities associated with ADCs and immunotherapy have heterogeneous presentations and pathogenesis requiring unique and often complex monitoring, and management.

AREAS COVERED

In this article, we provide an updated review of treatment-emergent ocular toxicity associated with new and novel oncologic therapies and summarize guidelines and best practice strategies for prevention, monitoring and management. A literature search was performed through PubMed, ClinicalTrials.gov, and FDA website (1 January 2017 to 10 May 2023) to identify relevant information.

EXPERT OPINION

The implementation of a strategy for monitoring, prevention, and management of treatment-related ocular toxicities involves a multi-disciplinary, often cross-center approach. Communication with infusion nursing leadership, clinic staff, and eye care providers is crucial to the successful implementation of eye care plans to prevent and manage ocular toxicity.

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.

Optimizing the safety of antibody-drug conjugates for patients with solid tumours

Over the past 5 years, improvements in the design of antibody-drug conjugates (ADCs) have enabled major advances that have reshaped the treatment of several advanced-stage solid tumours. Considering the intended rationale behind the design of ADCs, which is to achieve targeted delivery of cytotoxic molecules by linking them to antibodies targeting tumour-specific antigens, ADCs would be expected to be less toxic than conventional chemotherapy. However, most ADCs are still burdened by off-target toxicities that resemble those of the cytotoxic payload as well as on-target toxicities and other poorly understood and potentially life-threatening adverse effects. Given the rapid expansion in the clinical indications of ADCs, including use in curative settings and various combinations, extensive efforts are ongoing to improve their safety. Approaches currently being pursued include clinical trials optimizing the dose and treatment schedule, modifications of each ADC component, identification of predictive biomarkers for toxicities, and the development of innovative diagnostic tools. In this Review, we describe the determinants of the toxicities of ADCs in patients with solid tumours, highlighting key strategies that are expected to improve tolerability and enable improvements in the treatment outcomes of patients with advanced-stage and those with early stage cancers in the years to come.

Treatment options for molecular subtypes of endometrial cancer in 2023

PURPOSE OF REVIEW

This article reviews treatment strategies in endometrial cancer by molecular subtype.

RECENT FINDINGS

The Cancer Genome Atlas (TCGA) classifies four molecular subtypes of endometrial cancer - mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H), copy number high (CNH)/p53abn, copy number low (CNL)/no specific molecular profile (NSMP), and POLEmut - which are validated and highly prognostic. Treatment consideration by subtype is now recommended. FDA-approved immune checkpoint inhibitors (ICIs) include pembrolizumab and dostarlimab for previously treated dMMR/MSI-H EC, and pembrolizumab/lenvatinib for mismatch repair-proficient/microsatellite-stable endometrial cancer, including CNH/p53abn and CNL/NSMP. ICIs are being studied as first-line therapy in advanced/recurrent endometrial cancer by MMR status, as well as in combination with other targeted agents. Trastuzumab is NCCN compendium listed for HER2-positive serous endometrial cancer, which are primarily p53-abnormal. Antibody-drug conjugates targeting low and high HER2 levels show promise in breast cancer, and are beginning to be studied in endometrial cancer. In addition to hormonal therapy, maintenance therapy with selinexor (XPO1-inhibitor) showed potential benefit in p53 -wildtype endometrial cancer and is being investigated prospectively. Multiple prospective trials are evaluating de-escalation of care for POLEmut endometrial cancer given favorable survival regardless of adjuvant therapy.

SUMMARY

Molecular subtyping has important prognostic and therapeutic implications and should be guiding patient management and clinical trial design in endometrial cancer.

Antibody-Drug Conjugates in Gynecologic Cancer

The present article reviews the current evidence for antibody-drug conjugates (ADCs) in gynecologic cancer. ADCs consist of a highly selective monoclonal antibody for a tumor-associated antigen and a potent cytotoxic payload conjugated through a linker. Overall, the toxicity profiles of ADCs are manageable. Ocular toxicity is a known class effect of some ADCs and is managed with prophylactic corticosteroid and vasoconstrictor eye drops as well as dose interruptions/holds and dose modifications. In ovarian cancer, mirvetuximab soravtansine, an ADC targeting alpha-folate receptor (FRα), received US Food and Drug Administration (FDA) accelerated approval in November 2022 after data from the single-arm phase III SORAYA trial. A second ADC targeting FRα, STRO-002, received FDA fast track designation in August 2021. Multiple studies with upifitamab rilsodotin, an ADC comprising a NaPi2B-binding antibody, are underway. In cervical cancer, tisotumab vedotin, an ADC-targeting tissue factor, received FDA accelerated approval in September 2021 after the phase II innovaTV 204 trial. Tisotumab vedotin in combination with chemotherapy and other targeted agents is currently being evaluated. Although there are no currently approved ADCs for endometrial cancer, there are many under active evaluation, including mirvetuximab soravtansine. Trastuzumab-deruxtecan (T-DXd), an ADC targeting human epidermal growth factor receptor 2 (HER2), is currently approved for HER2-positive and HER2-low breast cancer and shows promise in endometrial cancer. Like all anticancer treatments, the decision for a patient to undergo therapy with an ADC is a personal choice that balances the potential benefits with the side effects and requires thorough and compassionate support of their physician and care team and shared decision making.

Safety and efficacy of mirvetuximab soravtansine, a folate receptor alpha (FRα)-targeting antibody-drug conjugate (ADC), in combination with bevacizumab in patients with platinum-resistant ovarian cancer

PURPOSE

Evaluate the antitumor activity and safety profile of the combination of mirvetuximab soravtansine and bevacizumab in patients with platinum-resistant ovarian cancer.

METHODS

Patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer, whose most recent platinum-free interval was ≤6 months, were administered mirvetuximab soravtansine (6 mg/kg adjusted ideal body weight) and bevacizumab (15 mg/kg), intravenously, once every 3 weeks. Eligibility included FRα expression by immunohistochemistry (IHC; ≥25% of cells with ≥2+ intensity). Prior bevacizumab and/or PARP inhibitor (PARPi) treatment were permitted. The primary endpoint was confirmed objective response rate (ORR). Secondary endpoints included duration of response (DOR), progression-free survival (PFS), and safety.

RESULTS

Ninety-four patients received combination treatment with mirvetuximab soravtansine and bevacizumab. Median age was 62 years (range, 39-81). Fifty-two percent had ≥3 prior therapies; 59% had prior bevacizumab; and 27% had prior PARPi. ORR was 44% (95% CI 33, 54) with 5 complete responses, median DOR 9.7 months (95% CI 6.9, 14.1), and median PFS 8.2 months (95% CI 6.8, 10.0). Treatment-related adverse events were consistent with the profiles of each agent, with the most common being blurred vision (all grades 57%; grade 3, 1%), diarrhea (54%; grade 3, 1%), and nausea (51%; grade 3, 1%).

CONCLUSION

The mirvetuximab soravtansine plus bevacizumab doublet is an active and well-tolerated regimen in patients with FRα-expressing platinum-resistant ovarian cancer. Promising activity was observed for patients regardless of level of FRα expression or prior bevacizumab. These data underscore the potential for mirvetuximab soravtansine as the combination partner of choice for bevacizumab in this setting.

Folate Receptor as a Biomarker and Therapeutic Target in Solid Tumors

Folate is a B vitamin necessary for basic biological functions, including rapid cell turnover occurring in cancer cell proliferation. Though the role of folate as a causative versus protective agent in carcinogenesis is debated, several studies have indicated that the folate receptor (FR), notably subtype folate receptor alpha (FRα), could be a viable biomarker for diagnosis, progression, and prognosis. Several cancers, including gastrointestinal, gynecological, breast, lung, and squamous cell head and neck cancers overexpress FR and are currently under investigation to correlate receptor status to disease state. Traditional chemotherapies have included antifolate medications, such as methotrexate and pemetrexed, which generate anticancer activity during the synthesis phase of the cell cycle. Increasingly, the repertoire of pharmacotherapies is expanding to include FR as a target, with a heterogenous pool of directed therapies. Here we discuss the FR, expression and effect in cancer biology, and relevant pharmacologic inhibitors.

Mirvetuximab Soravtansine: First Approval

Mirvetuximab soravtansine (mirvetuximab soravtansine-gynx; Elahere^™) is an antibody-drug conjugate (ADC), which is comprised of a folate receptor α (FRα) directed antibody conjugated to a microtubule inhibitor via a cleavable linker. The ADC is being developed by ImmunoGen for the treatment of FRα expressing cancers. In November 2022, mirvetuximab soravtansine was approved in the USA 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. This article summarizes the milestones in the development of mirvetuximab soravtansine leading to this first approval.

Strategies for Prevention and Management of Ocular Events Occurring With Mirvetuximab Soravtansine

Mirvetuximab soravtansine (MIRV) is a first-in-class antibody-drug conjugate (ADC) targeting folate receptor alpha (FRα) and is indicated for the treatment of adult patients with FRα-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer who have received 1 to 3 prior systemic treatment regimens. MIRV has demonstrated single-agent anticancer activity in clinical trials, with a differentiated safety profile comprising primarily low-grade, resolvable gastrointestinal and ocular adverse events (AEs). Pooled safety analysis of 464 MIRV-treated patients across 3 trials, including the phase 2 SORAYA study, found that 50% of patients had ≥1 ocular AEs of interest (AEIs) of blurred vision or keratopathy, the majority being grade ≤2. Grade 3 ocular AEIs occurred in 5% of patients, and 1 patient (0.2%) had a grade 4 event of keratopathy. All grade ≥2 AEIs of blurred vision and keratopathy resolved to grade 1 or 0 in patients with complete follow-up data. MIRV-associated ocular AEs were primarily characterized by resolvable changes to the corneal epithelium, with no cases of corneal ulcers or perforations. This reflects the distinctive, milder ocular safety profile for MIRV compared with that of other ADCs with ocular toxicities in clinical use. To maintain a generally low incidence of severe ocular AEs, patients should follow recommendations for maintaining ocular surface health, including daily use of lubricating eye drops and periodic use of corticosteroid eye drops, and should undergo an eye examination at baseline, at every other cycle for the first 8 cycles of treatment, and as clinically indicated. Dose modification guidelines should be followed to maximize patients' ability to remain on therapy. Close collaboration between all care team members, including oncologists and eye care professionals, will help patients benefit from this novel and promising anticancer agent. This review focuses on the etiology, rates, prevention, and management of MIRV-associated ocular events.

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.

Efficacy and Safety of Mirvetuximab Soravtansine in Patients With Platinum-Resistant Ovarian Cancer With High Folate Receptor Alpha Expression: Results From the SORAYA Study

PURPOSE

Single-agent chemotherapies have limited activity and considerable toxicity in patients with platinum-resistant epithelial ovarian cancer (PROC). Mirvetuximab soravtansine (MIRV) is an antibody-drug conjugate targeting folate receptor α (FRα). SORAYA is a single-arm, phase II study evaluating efficacy and safety of MIRV in patients with PROC.

METHODS

SORAYA enrolled FRα-high patients with PROC who had received one to three prior therapies, including required bevacizumab. The primary end point was confirmed objective response rate (ORR) by investigator; duration of response was the key secondary end point.

RESULTS

One hundred six patients were enrolled; 105 were evaluable for efficacy. All patients had received prior bevacizumab, 51% had three prior lines of therapy, and 48% received a prior poly ADP-ribose polymerase inhibitor. Median follow-up was 13.4 months. ORR was 32.4% (95% CI, 23.6 to 42.2), including five complete and 29 partial responses. The median duration of response was 6.9 months (95% CI, 5.6 to 9.7). In patients with one to two priors, the ORR by investigator was 35.3% (95% CI, 22.4 to 49.9) and in patients with three priors was 30.2% (95% CI, 18.3 to 44.3). The ORR by investigator was 38.0% (95% CI, 24.7 to 52.8) in patients with prior poly ADP-ribose polymerase inhibitor exposure and 27.5% (95% CI, 15.9 to 41.7) in those without. The most common treatment-related adverse events (all grade and grade 3-4) were blurred vision (41% and 6%), keratopathy (29% and 9%), and nausea (29% and 0%). Treatment-related adverse events led to dose delays, reductions, and discontinuations in 33%, 20%, and 9% of patients, respectively.

CONCLUSION

MIRV demonstrated consistent clinically meaningful antitumor activity and favorable tolerability and safety in patients with FRα-high PROC who had received up to three prior therapies, including bevacizumab, representing an important advance for this biomarker-selected population.

Mechanisms of ADC Toxicity and Strategies to Increase ADC Tolerability

Anti-cancer antibody-drug conjugates (ADCs) aim to expand the therapeutic index of traditional chemotherapy by employing the targeting specificity of monoclonal antibodies (mAbs) to increase the efficiency of the delivery of potent cytotoxic agents to malignant cells. In the past three years, the number of ADCs approved by the Food and Drug Administration (FDA) has tripled. Although several ADCs have demonstrated sufficient efficacy and safety to warrant FDA approval, the clinical use of all ADCs leads to substantial toxicity in treated patients, and many ADCs have failed during clinical development due to their unacceptable toxicity profiles. Analysis of the clinical data has demonstrated that dose-limiting toxicities (DLTs) are often shared by different ADCs that deliver the same cytotoxic payload, independent of the antigen that is targeted and/or the type of cancer that is treated. DLTs are commonly associated with cells and tissues that do not express the targeted antigen (i.e., off-target toxicity), and often limit ADC dosage to levels below those required for optimal anti-cancer effects. In this manuscript, we review the fundamental mechanisms contributing to ADC toxicity, we summarize common ADC treatment-related adverse events, and we discuss several approaches to mitigating ADC toxicity.

Ultrasmall Folate Receptor Alpha Targeted Enzymatically Cleavable Silica Nanoparticle Drug Conjugates Augment Penetration and Therapeutic Efficacy in Models of Cancer

To address the key challenges in the development of next-generation drug delivery systems (DDS) with desired physicochemical properties to overcome limitations regarding safety, in vivo efficacy, and solid tumor penetration, an ultrasmall folate receptor alpha (FRα) targeted silica nanoparticle (C'Dot) drug conjugate (CDC; or folic acid CDC) was developed. A broad array of methods was employed to screen a panel of CDCs and identify a lead folic acid CDC for clinical development. These included comparing the performance against antibody-drug conjugates (ADCs) in three-dimensional tumor spheroid penetration ability, assessing in vitro/ex vivo cytotoxic efficacy, as well as in vivo therapeutic outcome in multiple cell-line-derived and patient-derived xenograft models. An ultrasmall folic acid CDC, EC112002, was identified as the lead candidate out of >500 folic acid CDC formulations evaluated. Systematic studies demonstrated that the lead formulation, EC112002, exhibited highly specific FRα targeting, multivalent binding properties that would mediate the ability to outcompete endogenous folate in vivo, enzymatic responsive payload cleavage, stability in human plasma, rapid in vivo clearance, and minimal normal organ retention organ distribution in non-tumor-bearing mice. When compared with an anti-FRα-DM4 ADC, EC112002 demonstrated deeper penetration into 3D cell-line-derived tumor spheroids and superior specific cytotoxicity in a panel of 3D patient-derived tumor spheroids, as well as enhanced efficacy in cell-line-derived and patient-derived in vivo tumor xenograft models expressing a range of low to high levels of FRα. With the growing interest in developing clinically translatable, safe, and efficacious DDSs, EC112002 has the potential to address some of the critical limitations of the current systemic drug delivery for cancer management.

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.

Antibody drug conjugates: The dos and don'ts in clinical development

Antibody Drug Conjugates (ADCs) entered clinical trials in the mid 1990s to selectively deliver cytotoxic chemotherapy to cancer cells with the goal to increase the antitumor activity and decrease normal tissue toxicity. Over nearly 30 years of development the ADC platform has become established with now 11 approved agents and many more in the pipeline. This review is designed to highlight some of the problems and solutions encountered in clinical development as well as provide practical instruction to both clinical investigators on the efficient protocol design for ADCs and the lessons learned.

Facts and Hopes in Immunotherapy of Endometrial Cancer

Immunotherapy with checkpoint inhibitors has changed the paradigm of treatment for many tumors, and endometrial carcinoma is not an exception. Approved treatment options are pembrolizumab or dostarlimab for mismatch repair deficient tumors, pembrolizumab for tumors with high mutational load, and, more recently, pembrolizumab/lenvatinib for all patients with endometrial cancer. Endometrial cancer is a heterogeneous disease with distinct molecular subtypes and different prognoses. Differences between molecular subgroups regarding antigenicity and immunogenicity should be relevant to develop more tailored immunotherapeutic approaches. In this review, we aim to summarize and discuss the current evidence-Facts, and future opportunities-Hopes-of immunotherapy for endometrial cancer, focusing on relevant molecular and tumor microenvironment features of The Cancer Genome Atlas endometrial cancer subtypes.

Biopolymeric Prodrug Systems as Potential Antineoplastic Therapy

Nowadays, cancer represents a major public health issue, a substantial economic issue, and a burden for society. Limited by numerous disadvantages, conventional chemotherapy is being replaced by new strategies targeting tumor cells. In this context, therapies based on biopolymer prodrug systems represent a promising alternative for improving the pharmacokinetic and pharmacologic properties of drugs and reducing their toxicity. The polymer-directed enzyme prodrug therapy is based on tumor cell targeting and release of the drug using polymer–drug and polymer–enzyme conjugates. In addition, current trends are oriented towards natural sources. They are biocompatible, biodegradable, and represent a valuable and renewable source. Therefore, numerous antitumor molecules have been conjugated with natural polymers. The present manuscript highlights the latest research focused on polymer–drug conjugates containing natural polymers such as chitosan, hyaluronic acid, dextran, pullulan, silk fibroin, heparin, and polysaccharides from Auricularia auricula.

Targeted therapy of pyrrolo[2,3-d]pyrimidine antifolates in a syngeneic mouse model of high grade serous ovarian cancer and the impact on the tumor microenvironment

Novel therapies are urgently needed for epithelial ovarian cancer (EOC), the most lethal gynecologic malignancy. In addition, therapies that target unique vulnerabilities in the tumor microenvironment (TME) of EOC have largely been unrealized. One strategy to achieve selective drug delivery for EOC therapy involves use of targeted antifolates via their uptake by folate receptor (FR) proteins, resulting in inhibition of essential one-carbon (C1) metabolic pathways. FRα is highly expressed in EOCs, along with the proton-coupled folate transporter (PCFT); FRβ is expressed on activated macrophages, a major infiltrating immune population in EOC. Thus, there is great potential for targeting both the tumor and the TME with agents delivered via selective transport by FRs and PCFT. In this report, we investigated the therapeutic potential of a novel cytosolic C1 6-substituted pyrrolo[2,3-d]pyrimidine inhibitor AGF94, with selectivity for uptake by FRs and PCFT and inhibition of de novo purine nucleotide biosynthesis, against a syngeneic model of ovarian cancer (BR-Luc) which recapitulates high-grade serous ovarian cancer in patients. In vitro activity of AGF94 was extended in vivo against orthotopic BR-Luc tumors. With late-stage subcutaneous BR-Luc xenografts, AGF94 treatment resulted in substantial anti-tumor efficacy, accompanied by significantly decreased M2-like FRβ-expressing macrophages and increased CD3+ T cells, whereas CD4+ and CD8+ T cells were unaffected. Our studies demonstrate potent anti-tumor efficacy of AGF94 in the therapy of EOC in the context of an intact immune system, and provide a framework for targeting the immunosuppressive TME as an essential component of therapy.

Praluzatamab Ravtansine, a CD166-Targeting Antibody-Drug Conjugate, in Patients with Advanced Solid Tumors: An Open-Label Phase I/II Trial

PURPOSE

Praluzatamab ravtansine (CX-2009) is a conditionally activated Probody drug conjugate (PDC) comprising an anti-CD166 mAb conjugated to DM4, with a protease-cleavable linker and a peptide mask that limits target engagement in normal tissue and circulation. The tumor microenvironment is enriched for proteases capable of cleaving the linker, thereby releasing the mask, allowing for localized binding of CX-2009 to CD166. CX-2009 was evaluated in a phase I/II clinical trial for patients with advanced solid tumors.

PATIENTS AND METHODS

Eligible patients had metastatic cancer receiving ≥2 prior treatments. CX-2009 was administered at escalating doses every 3 weeks (0.25-10 mg/kg) or every 2 weeks (4-6 mg/kg). Primary objective was to determine the safety profile and recommended phase II dose (RP2D).

RESULTS

Of 99 patients enrolled, the most prevalent subtype was breast cancer (n = 45). Median number of prior therapies was 5 (range, 1-19). Dose-limiting toxicities were observed at 8 mg/kg every 3 weeks and 6 mg/kg every 2 weeks. On the basis of tolerability, the RP2D was 7 mg/kg every 3 weeks. Tumor regressions were observed at doses ≥4 mg/kg. In the hormone receptor-positive/HER2-nonamplified breast cancer subset (n = 22), 2 patients (9%) had confirmed partial responses, and 10 patients (45%) had stable disease. Imaging with zirconium-labeled CX-2009 confirmed uptake in tumor lesions and shielding of major organs. Activated, unmasked CX-2009 was measurable in 18 of 22 posttreatment biopsies.

CONCLUSIONS

CD166 is a novel, ubiquitously expressed target. CX-2009 is the first conditionally activated antibody-drug conjugate to CD166 to demonstrate both translational and clinical activity in a variety of tumor types.