Mirvetuximab soravtansine: A breakthrough in targeted therapy for platinum-resistant ovarian cancer.

Ovarian cancer, ranked as the second leading cause of gynecologic malignancy-related deaths globally, poses a formidable challenge despite advances in early detection and treatment modalities. This paper explores the efficacy and safety of mirvetuximab soravtansine, the first folate receptor alpha (FRα)-targeting antibody-drug conjugate, in platinum-resistant ovarian cancer expressing FRα. A review of 4 key studies involving 453 participants consistently demonstrates mirvetuximab soravtansine's clinically meaningful antitumor activity and favorable safety profile. Clinical implications emphasize mirvetuximab soravtansine's pivotal role in targeted therapy, especially for high FRα-expressing tumors, potentially reshaping platinum-resistant ovarian cancer management. The combination therapy approach introduces a novel dimension, suggesting enhanced therapeutic outcomes. Even in heavily pretreated patients, mirvetuximab soravtansine's favorable tolerability positions it as a viable option. The reliability of archival tissue for FRα assessment simplifies patient selection, streamlining accessibility to targeted therapies. However, identified gaps, including limited diversity in patient populations, sparse quality of life data, and the need for long-term safety information, indicate areas for future research. Exploration of additional biomarkers predicting mirvetuximab soravtansine responsiveness is essential for personalized treatment.

Phase 1b study of mirvetuximab soravtansine, a folate receptor alpha (FRα)-targeting antibody-drug conjugate, in combination with carboplatin and bevacizumab in patients with platinum-sensitive ovarian cancer.

OBJECTIVE: Evaluate the antitumor activity and safety profile of the triplet combination of mirvetuximab soravtansine (MIRV), carboplatin, and bevacizumab in recurrent, platinum-sensitive ovarian cancer. METHODS: Participants with recurrent, platinum-sensitive epithelial ovarian, fallopian tube, or primary peritoneal cancer (1-2 prior lines of therapy) received MIRV (6 mg/kg adjusted ideal body weight), carboplatin (AUC5), and bevacizumab (15 mg/kg) once every 3 weeks. Carboplatin could be discontinued after 6 cycles per investigator discretion; continuation of MIRV+bevacizumab as maintenance therapy was permitted. Eligibility included folate receptor alpha (FRα) expression by immunohistochemistry (≥50% of cells with ≥2+ intensity; PS2+ scoring); prior bevacizumab was allowed. Tumor response, duration of response (DOR), progression-free survival (PFS), and adverse events (AEs) were assessed. RESULTS: Forty-one participants received triplet therapy, with a median of 6, 12, and 13 cycles of carboplatin, MIRV, and bevacizumab, respectively. The confirmed objective response rate was 83% (9 complete and 25 partial responses). The median DOR was 10.9 months; median PFS was 13.5 months. AEs (any grade) occurred as expected, based on each agent's safety profile; most common were diarrhea (83%), nausea (76%), fatigue (73%), thrombocytopenia (71%), and blurred vision (68%). Most cases were mild to moderate (grade ≤2), except for thrombocytopenia, for which most drug-related discontinuations occurred, and neutropenia. CONCLUSIONS: This triplet regimen (MIRV+carboplatin+bevacizumab) was highly active, with a tolerable AE profile in participants with recurrent, platinum-sensitive, FRα-expressing ovarian cancer. Thrombocytopenia was the primary cause of dose modifications. These outcomes compare favorably to historical data reported for platinum-based chemotherapy plus bevacizumab regimens in similar patient populations.

Mirvetuximab Soravtansine in FRα-Positive, Platinum-Resistant Ovarian Cancer.

BACKGROUND: Mirvetuximab soravtansine-gynx (MIRV), a first-in-class antibody-drug conjugate targeting folate receptor α (FRα), is approved for the treatment of platinum-resistant ovarian cancer in the United States. METHODS: We conducted a phase 3, global, confirmatory, open-label, randomized, controlled trial to compare the efficacy and safety of MIRV with the investigator's choice of chemotherapy in the treatment of platinum-resistant, high-grade serous ovarian cancer. Participants who had previously received one to three lines of therapy and had high FRα tumor expression (≥75% of cells with ≥2+ staining intensity) were randomly assigned in a 1:1 ratio to receive MIRV (6 mg per kilogram of adjusted ideal body weight every 3 weeks) or chemotherapy (paclitaxel, pegylated liposomal doxorubicin, or topotecan). The primary end point was investigator-assessed progression-free survival; key secondary analytic end points included objective response, overall survival, and participant-reported outcomes. RESULTS: A total of 453 participants underwent randomization; 227 were assigned to the MIRV group and 226 to the chemotherapy group. The median progression-free survival was 5.62 months (95% confidence interval [CI], 4.34 to 5.95) with MIRV and 3.98 months (95% CI, 2.86 to 4.47) with chemotherapy (P<0.001). An objective response occurred in 42.3% of the participants in the MIRV group and in 15.9% of those in the chemotherapy group (odds ratio, 3.81; 95% CI, 2.44 to 5.94; P<0.001). Overall survival was significantly longer with MIRV than with chemotherapy (median, 16.46 months vs. 12.75 months; hazard ratio for death, 0.67; 95% CI, 0.50 to 0.89; P = 0.005). During the treatment period, fewer adverse events of grade 3 or higher occurred with MIRV than with chemotherapy (41.7% vs. 54.1%), as did serious adverse events of any grade (23.9% vs. 32.9%) and events leading to discontinuation (9.2% vs. 15.9%). CONCLUSIONS: Among participants with platinum-resistant, FRα-positive ovarian cancer, treatment with MIRV showed a significant benefit over chemotherapy with respect to progression-free and overall survival and objective response. (Funded by ImmunoGen; MIRASOL ClinicalTrials.gov number, NCT04209855.).

Safety profile of trastuzumab-emtansine (T-DM1) with concurrent radiation therapy: A systematic review and meta-analysis.

BACKGROUND AND PURPOSE: In recent years, the treatment landscape for breast cancer has undergone significant advancements, with the introduction of several new anticancer agents. One such agent is trastuzumab emtansine (T-DM1), an antibody drug conjugate that has shown improved outcomes in both early and advanced breast cancer. However, there is currently a lack of comprehensive evidence regarding the safety profile of combining T-DM1 with radiation therapy (RT). In this study, we aim to provide a summary of the available data on the safety of combining RT with T-DM1 in both early and metastatic breast cancer settings. MATERIALS AND METHODS: This systematic review and meta-analysis project is part of the consensus recommendations by the European Society for Radiotherapy and Oncology (ESTRO) Guidelines Committee on integrating RT with targeted treatments for breast cancer. A thorough literature search was conducted using the PUBMED/MedLine, Embase, and Cochrane databases to identify original studies focusing on the safety profile of combining T-DM1 with RT. RESULTS: After applying eligibility criteria, nine articles were included in the meta-analysis. Pooled data from these studies revealed a high incidence of grade 3 + radionecrosis (17%), while the rates of grade 3 + radiation-related pneumonitis (<1%) and skin toxicity (1%) were found to be very low. CONCLUSION: Although there is some concern regarding a slight increase in pneumonitis when combining T-DM1 with postoperative RT, the safety profile of this combination was deemed acceptable for locoregional treatment in non-metastatic breast cancer. However, caution is advised when irradiating intracranial sites concurrently with T-DM1. There is a pressing need for international consensus guidelines regarding the safety considerations of combining T-DM1 and RT for breast cancer.

High risks adverse events associated with trastuzumab emtansine and trastuzumab deruxtecan for the treatment of HER2-positive/mutated malignancies: a pharmacovigilance study based on the FAERS database.

BACKGROUND: T-DM1 and T-DXd are two promising antibody-drug conjugates for treating advanced HER2-positive breast cancer and HER2-mutated lung cancer. Understanding the differences in the adverse events (AEs) profile of both drugs may help clinicians make an appropriate treatment decision. RESEARCH DESIGN AND METHODS: All data obtained from the FDA Adverse Event Reporting System (FAERS) database from Q1 2004 to Q3 2022 underwent disproportionality analysis and Bayesian analysis to detect and assess the AE signals of T-DM1 and T-DXd for comparison. RESULTS: A total of 2,113 and 1,269 AE reports associated with T-DM1 and T-Dxd, respectively, were retrieved from FAERS database, in which, respondents were mostly elderly women. Their statistical differences (p < 0.001), poses high incidence of thrombocytopenia, including cardiotoxicity (p < 0.05) for T-DM1, while myelosuppression, interstitial lung disease (ILD), and pneumonitis for T-DXd. Splenomegaly, nodular regenerative hyperplasia, hepatic cirrhosis, portal hypertension, neuropathy peripheral, and spider nevus, are particular to T-DM1. Similarly, febrile neutropenia, pneumocystis jirovecii pneumonia, neutrophil count decreased, and KL-6 increased, are unique to T-DXd. CONCLUSIONS: T-DXd is more likely to induce ILD/pneumonia and myelosuppression than T-DM1, whereas T-DM1 has higher risk of hepatotoxicity, cardiotoxicity, and thrombocytopenia than T-DXd. T-DM1-related hepatotoxicity may need redefinition. Clinicians may need to balance the benefits and risks of antibody-drug conjugates treatment for certain patients.

A nationwide observational study in heavily pretreated metastatic HER2-positive breast cancer patients.

BACKGROUND: Current guidelines in HER2-positive metastatic breast cancer (mBC) recommend the combination of trastuzumab and a chemotherapeutic agent for 3rd line or later treatments. This study aims to describe the treatment of HER2-positive mBC in 3rd line or later after previous treatment with T-DM1 for mBC in a real-world setting. MATERIAL AND METHODS: This observational population-based study included all women diagnosed with HER2-positive mBC in Denmark, previously treated with T-DM1 in the metastatic setting. Patients were included on the date of progression leading to initiation of 3rd line treatment if the patient had received T-DM1 in 1st or 2nd line. If the patient received T-DM1 in 3rd line or later the inclusion was based on the date of progression on T-DM1. The primary end points were overall survival (OS) and progression-free survival (PFS). RESULTS: The study included 272 women with a mean age of 59 (27-86) and a median of 3 (2-11) treatment lines prior to inclusion. At index, all patients had received T-DM1 and 167 (62%) patients had received pertuzumab in the metastatic setting. During follow-up 183 patients received chemotherapy. Of these patients, 120 received chemotherapy combined with trastuzumab, 50 received chemotherapy combined with other HER2-targeted therapy, and 13 received chemotherapy as monotherapy. The remaining 89 patients received either HER2-targeted monotherapy (41), endocrine therapy (31), experimental treatment (10), or no treatment (7). Median PFS was 5.5 months (95% CI, 4.8-6.5) and median OS was 18.5 months (95% CI, 16.2-21.3). CONCLUSION: In this real-world study, we found that patients were treated with a wide variety of anti-cancer agents with modest efficacy. However, patients in this study did not have access to newer therapies like tucatinib and T-DXd.

Acute skin radiation toxicity seen with concurrent T-DM1: A single institutional report of 35 patients.

Trastuzumab emtansine (T-DM1) is a novel therapeutic for HER2+ breast cancer patients with residual disease after neoadjuvant chemotherapy. Concurrent radiotherapy (RT) is offered to a subset of patients based on results from the KATHERINE trial which showed a favorable safety profile. With emerging therapies that necessitate concurrent RT, we must closely follow rates of skin toxicity. Our first 35 patients who underwent concurrent T-DM1 treatment with breast/chest wall (CW) ± nodal irradiation are reported. Most patients (22/35) had grade 2+ toxicity and 3 patients had grade 3 toxicities. We add our experience with radiation dermatitis and concurrent T-DM1 to contribute to existing reports.

Concomitant Use of Ado-trastuzumab Emtansine and Imatinib in a Patient of CML and Metastatic Breast Cancer.

Imatinib is a CYP3A4 inhibitor, while ado-trastuzumab is a CYP3A4 substrate. Imatinib can interact with ado-trastuzumab emtansine (T-DM1) and can increase T-DM1 concentrations, leading to T-DM1-related toxicity. There is no trial or case report in the literature on the concomitant use of Imatinib and T-DM1. Herein, we report a case in which T-DM1 was used effectively with imatinib in a patient with chronic myeloid leukaemia (CML) and metastatic Her-2-positive breast cancer. A 37-year female using imatinib for CML was diagnosed with breast cancer and a modified radical mastectomy was performed. Skin metastasis occurred within one year after adjuvant therapy was completed. Lung metastasis occurred after Trastuzumab + vinorelbine treatment and T-DM1 and imatinib were given to the patient. No side effects were observed except for grade 1 fatigue. This case report is the first to report the concomitant use of T-DM1 and imatinib in a patient of CML and metastatic breast cancer. Key Words: Imatinib, Ado-trastuzumab emtansine, Breast cancer, Chronic myeloid leukaemia.

Therapeutic landscape of advanced HER2-positive breast cancer in 2022.

HER2-positive breast cancer is an aggressive subtype of breast cancer with five-year survival rates of 30% for the advanced stage. The development of anti-HER2 treatments has led to a paradigm shift in the management and clinical outcomes of advanced HER2-positive breast cancer patients. The standard first-line treatment consists of taxane-based chemotherapy plus dual anti-HER2 therapies with trastuzumab and pertuzumab. The antibody-drug conjugate (ADC) ado-trastuzumab emtansine (T-DM1) has been a second-line therapeutic standard, but the second-line treatment approach is rapidly evolving. Given a substantial advantage of another ADC, Fam-trastuzumab deruxtecan (T-DXd), compared to T-DM1 in a recent randomized trial in the second-line setting, T-DXd is currently the preferred second-line option. Optimal third-line treatment strategies are still not established, and multiple approaches have been used including combinations based on capecitabine, trastuzumab, or both with oral anti-HER2 tyrosine kinase inhibitors. Tucatinib plus capecitabine and trastuzumab, lapatinib plus trastuzumab, neratinib or lapatinib plus capecitabine are some of the FDA approved combinations. Another newer agent approved for third- or later-line therapy in the metastatic setting is margetuximab, an Fc-engineered anti-HER2 monoclonal antibody, in combination with chemotherapy. Other novel agents currently under clinical trials are the drugs that indirectly target HER2, including immune cell cycle inhibitors, PI3K/mTOR inhibitors, and immunotherapy agents.

Real-World Outcomes in Patients With Brain Metastases Secondary to HER2-Positive Breast Cancer: An Australian Multi-centre Registry-based Study.

BACKGROUND: The development of brain metastases occurs commonly in HER2-positive metastatic breast cancer and is associated with a poorer prognosis. The advent of HER2-targeted therapy has improved overall survival, but the benefit in patients with brain metastases is unclear, as these patients are often excluded from clinical trials. This study aimed to explore real-world outcomes in patients with brain metastases in HER2-positive MBC. MATERIALS & METHODS: Data was extracted from the TABITHA registry, which consists of patient data collected prospectively from 16 Australian sites from 24th February 2015 to 31st October 2021. Data analysed included characteristics of brain metastases, treatment received and survival outcomes. RESULTS: A total of 135 (37%) of 361 patients with HER2-positive MBC were diagnosed with brain metastases during their clinical course, including 45 (12%) with brain metastases at time of MBC diagnosis. 61 (45%) had ≥4 brain lesions. The most common local therapy given was whole brain radiation therapy (WBRT) (36%) followed by multi-modality treatment with both surgery and radiation therapy (27%). The majority of patients received first-line HER2-targeted treatment with trastuzumab and pertuzumab followed by second-line trastuzumab emtansine (T-DM1) but third-line therapy was heterogenous. The median overall survival in patients who developed brain metastases was significantly shorter than those who did not develop brain metastases (58.9 vs. 96.1 months, P = .02). CONCLUSION: Real-world patients diagnosed with brain metastases in HER2-positive MBC have a relatively poor prognosis, despite advances in HER2-targeted treatment. As the range of HER2-targeted treatment expands, it is important to pursue clinical trials that focus on patients with brain metastases.

Ado-trastuzumab emtansine associated spider telangiectasia.

INTRODUCTION: Breast cancer is the most common cancer in women. Human epidermal growth factor receptor 2 (HER2) positivity rate is 20% and generally has a poor prognosis. Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate consisting of HER2 target monoclonal antibody trastuzumab and microtubule inhibitor emtansine. The most common side effects are fatigue, diarrhea, anemia, and it is generally a safe and tolerable agent. CASE REPORT: In our case, we reported our patient who developed mucosal and cutaneous telangiectasia after T-DM1 treatment and who had a complete response in metastases after skin lesions. MANAGEMENT AND OUTCOME: While no side effects were observed during the use of T-DM1 for HER2 positive disease, nose bleeding and spider telangiectasia on the skin developed in the 9th month of the treatment. In these lesions, which did not require any treatment, no regression was observed during T-DM1 treatment. DISCUSSION: We think that T-DM1, which was detected with a low incidence of skin toxicity in studies, may form telangiectatic lesions due to vascular dilatation through emtansine, and therefore care should be taken in the treatment of T-DM1.

Comparison of the Efficacy, Safety, Pharmacokinetic and Immunogenicity of UJVIRA (ZRC-3256, Trastuzumab Emtansine) With the Kadcyla (Trastuzumab Emtansine) in the Treatment of HER2-Positive Metastatic Breast Cancer: A Randomized, Open-Label, Multicenter Study in India.

BACKGROUND: UJVIRA is the first DCGI approved biosimilar of trastuzumab emtansine (Kadcyla) which may offer an alternative cost-effective treatment option for human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer patients in India. This article summarizes the available clinical evidence supporting the biosimilarity of UJVIRA and Kadcyla with respect to efficacy, pharmacokinetic, safety, and immunogenicity. MATERIALS AND METHODS: A phase 3, randomized, open-label, active-controlled study was conducted at 31 sites across India. A total of 168 patients were enrolled and randomized to receive either UJVIRA or Kadcyla. Of which, only first 50 patients were included in pharmacokinetic assessment. UJVIRA or Kadcyla were administered at a dose of 3.6 mg/kg by intravenous infusion every 3 weeks (21 days) for 8 cycles or until disease progression or unmanageable toxicity, whichever was earlier. The study assessed efficacy (ORR), safety, pharmacokinetics, and immunogenicity. RESULTS: The ORR at the end of Week 24 was 37.76% in the UJVIRA and 33.33% in the Kadcyla group. The risk difference was 4.42% [-12.01, 20.85]. It met noninferiority margin of -15%. The pharmacokinetic parameters were comparable between groups. No antidrug antibody was detected in any of the treatment groups. The overall safety profile in terms of TEAEs and laboratory abnormalities was also comparable between the treatment groups. CONCLUSION: Results demonstrated biosimilarity between UJVIRA and Kadcyla in terms of efficacy, safety, pharmacokinetics, and immunogenicity. Therefore, UJVIRA could prove to be a cost-effective treatment alternative for HER2-positive metastatic breast cancer patients in India.

Impact of obesity on safety outcomes and treatment modifications with ado-trastuzumab emtansine in breast cancer patients.

INTRODUCTION: Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate indicated for the treatment of HER2-positive breast cancer. The 2012 American Society of Clinical Oncology guidelines on chemotherapy dosing in obesity recommend using full weight-based cytotoxic chemotherapy doses to treat obese patients with cancer. These guidelines were published prior to the advent of anticancer antibody-drug conjugates. There is a need to investigate the safety of T-DM1 in obese patients. METHODS: This retrospective chart review included adult patients with breast cancer receiving T-DM1. The primary endpoint was a composite of the incidence of T-DM1 treatment modifications secondary to an adverse event. Secondary outcomes included the incidence of dose reductions, dose delays, treatment discontinuations, and adverse events. RESULTS: A total of 119 patients with HER2-positive breast cancer who received T-DM1 therapy were included in this study: 44 obese patients and 75 non-obese patients. The composite outcome of treatment modifications due to toxicity was significantly higher in obese patients compared to non-obese patients (45% vs 25%, p = 0.024). Treatment delays were significantly higher in obese patients (36% vs 16%, p = 0.011). All-grade adverse events with a higher incidence in obese patients included left ventricular ejection fraction decrease (11% vs 5%), bilirubin increase (32% vs 12%), thrombocytopenia (61% vs 55%), and peripheral neuropathy (34% vs 27%). CONCLUSIONS: This study suggests obese patients receiving T-DM1 may require more treatment modifications secondary to adverse events compared to non-obese patients. Larger studies are needed to determine if obese patients are at higher risk for specific T-DM1-induced adverse events.

Trastuzumab does not bind rat or mouse ErbB2/neu: implications for selection of non-clinical safety models for trastuzumab-based therapeutics.

PURPOSE: Assessment of non-clinical safety signals relies on understanding species selectivity of antibodies. This is particularly important with antibody-drug conjugates, where it is key to determine target-dependent versus target-independent toxicity. Although it appears to be widely accepted that trastuzumab does not bind mouse or rat HER2/ErbB2/neu, numerous investigators continue to use mouse models to investigate safety signals of trastuzumab and trastuzumab emtansine (T-DM1). We, therefore, conducted a broad array of both binding and biologic studies to demonstrate selectivity of trastuzumab for human HER2 versus mouse/rat neu. METHODS: Binding of anti-neu and anti-HER2 antibodies was assessed by ELISA, FACS, IHC, Scatchard, and immunoblot methods in human, rat, and mouse cell lines. In human hepatocytes, T-DM1 uptake and catabolism were measured by LC-MS/MS; cell viability changes were determined using CellTiter-Glo. RESULTS: Our data demonstrate, using different binding methods, lack of trastuzumab binding to rat or mouse neu. Structural studies show important amino acid differences in the trastuzumab-HER2 binding interface between mouse/rat and human HER2 ECD. Substitution of these rodent amino acid residues into human HER2 abolish binding of trastuzumab. Cell viability changes, uptake, and catabolism of T-DM1 versus a DM1 non-targeted control ADC were comparable, indicating target-independent effects of the DM1-containing ADCs. Moreover, trastuzumab binding to human or mouse hepatocytes was not detected. CONCLUSIONS: These data, in total, demonstrate that trastuzumab, and by extension T-DM1, do not bind rat or mouse neu, underscoring the importance of species selection for safety studies investigating trastuzumab or trastuzumab-based therapeutics.