Trastuzumab deruxtecan (DS-8201a), a HER2-targeting antibody-drug conjugate with topoisomerase I inhibitor payload, shows antitumor activity in uterine and ovarian carcinosarcoma with HER2/neu expression

Small Molecule-Drug Conjugates Emerge as a New Promising Approach for Cancer Treatment

Antibody drug conjugates (ADCs) have emerged as a new promising class of anti- cancer agents. However, limitations such as higher costs and unavoidable immunogenicity due to their relatively large structures cannot be ignored. Therefore, the development of lightweight drugs such as small molecule-drug conjugates (SMDCs) based on the ADC design idea has become a new option for targeted therapy. SMDCs are derived from the coupling of small-molecule targeting ligands with cytotoxic drugs. They are composed of three parts: small-molecule targeting ligands, cytotoxic molecules, and linkers. Compared with ADCs, SMDCs can be more rapidly and evenly dispersed into tumor tissues, with low cost and no immunogenicity. In this article, we will give a comprehensive review of different types of SMDCs currently under clinical trials to provide ideas and inspirations for the development of clinically applicable SMDCs.

In Vivo and In Vitro Efficacy of Trastuzumab Deruxtecan in Uterine Serous Carcinoma

Uterine serous carcinoma (USC) is a rare, biologically aggressive variant of endometrial cancer with a high recurrence rate and poor prognosis. HER2 overexpression (3+ positivity) by IHC and/or FISH ERBB2 gene amplification is detected in approximately one-third of patients with USC. Clinical trials incorporating trastuzumab with standard chemotherapy have recently demonstrated improved progression-free and overall survival in advanced-stage or recurrent USC that overexpresses HER2. However, a large number of patients with USC eventually developed resistance to trastuzumab. Trastuzumab deruxtecan (T-DXd) is a novel HER2-directed antibody-drug conjugate with a topoisomerase I inhibitor payload recently approved by the Food and Drug Administration (FDA) for multiple tumor indications. Here, we investigated the in vitro and in vivo efficacy of T-DXd in primary USC cell lines and xenografts with different HER2 expression. T-DXd-induced cell growth suppression in HER2-overexpressing cell lines in vitro, increased early and late apoptosis as assessed by annexin and propidium iodide staining, and, similarly to trastuzumab, T-DXd-induced significant antibody-dependent cellular cytotoxicity in the presence of peripheral blood lymphocytes. While negligible activity was detected against USC cell lines with low HER2 expression, T-DXd demonstrated significant bystander killing against USC tumors with low/negligible HER2 when such cells were admixed with HER2 3+ tumor cells in vitro. T-DXd showed tumor growth suppression in in vivo USC PDX models that overexpress HER2 at 3+ levels, prolonging survival when compared with controls, with minimal toxicity. Future clinical trials are warranted in patients with USC failing trastuzumab treatment.

Response of low HER2-expressing ovarian carcinosarcoma to trastuzumab deruxtecan, a case report

•Treatment options are limited for recurrent ovarian carcinosarcoma (OCS).•A patient with HER2 1 + IHC and negative FISH amplification was treated with trastuzumab deruxtecan.•A durable partial response was achieved, suggesting a possible treatment option for OCS patients with HER2 expression.

Genomic and Molecular Characteristics of Ovarian Carcinosarcoma

Ovarian carcinosarcoma (OCS) is a rare malignancy with a poor prognosis. It is a biphasic tumor with malignant epithelial and mesenchymal components. A few mutations commonly seen in cancer have been identified in OCS, including TP53, PIK3CA, c-myc, ZNF217, ARID1A, and CTNNB1. Some OCS tumors have shown vascular endothelial growth factor positivity and limited HER2 expression. There is evidence of homologous recombination deficiency in OCS. This malignancy can be categorized as copy number high but has not been shown to have a high tumor mutational burden. There are mixed findings regarding the presence of biomarkers targeted by immune checkpoint inhibitors in OCS. For treatments other than systemic chemotherapy, the data available are largely based on in vitro and in vivo studies. In addition, there are case reports citing the use of poly-ADP ribose polymerase inhibitors, vascular endothelial growth factor inhibitors, and immunotherapy with varying degrees of success. This review paper will discuss the molecular and genomic characteristics of OCS, which can guide future treatment strategies.

Antibody-Drug Conjugates (ADC) in HER2/neu-Positive Gynecologic Tumors

Antibody-drug conjugates (ADCs) are a new class of targeted anti-cancer therapies that combine a monoclonal tumor-surface-receptor-targeting antibody with a highly cytotoxic molecule payload bonded through specifically designed cleavable or non-cleavable chemical linkers. One such tumor surface receptor is human epidermal growth factor 2 (HER2), which is of interest for the treatment of many gynecologic tumors. ADCs enable the targeted delivery of a variety of cytotoxic therapies to tumor cells while minimizing delivery to healthy tissues. This review summarizes the existing literature about HER2-targeting ADC therapies approved for use in gynecologic malignancies, relevant preclinical studies, strategies to address ADC resistance, and ongoing clinical trials.

Empower the Potential of Trastuzumab Deruxtecan with Novel Combinations

Trastuzumab deruxtecan (T-DXd) is reshaping the therapeutic landscape of HER2-positive tumors. A recent article reports on the preclinical activity of the combination of T-DXd plus adavosertib, WEE1 kinase inhibitor, which promises to expand the use of this antibody-drug conjugate in HER2-positive tumors with CCNE1 coamplification. See related article by DiPeri et al., p. 4385.

Adavosertib Enhances Antitumor Activity of Trastuzumab Deruxtecan in HER2-Expressing Cancers

PURPOSE

Cyclin E (CCNE1) has been proposed as a biomarker of sensitivity to adavosertib, a Wee1 kinase inhibitor, and a mechanism of resistance to HER2-targeted therapy.

EXPERIMENTAL DESIGN

Copy number and genomic sequencing data from The Cancer Genome Atlas and MD Anderson Cancer Center databases were analyzed to assess ERBB2 and CCNE1 expression. Molecular characteristics of tumors and patient-derived xenografts (PDX) were assessed by next-generation sequencing, whole-exome sequencing, fluorescent in situ hybridization, and IHC. In vitro, CCNE1 was overexpressed or knocked down in HER2+ cell lines to evaluate drug combination efficacy. In vivo, NSG mice bearing PDXs were subjected to combinatorial therapy with various treatment regimens, followed by tumor growth assessment. Pharmacodynamic markers in PDXs were characterized by IHC and reverse-phase protein array.

RESULTS

Among several ERBB2-amplified cancers, CCNE1 co-amplification was identified (gastric 37%, endometroid 43%, and ovarian serous adenocarcinoma 41%). We hypothesized that adavosertib may enhance activity of HER2 antibody-drug conjugate trastuzumab deruxtecan (T-DXd). In vitro, sensitivity to T-DXd was decreased by cyclin E overexpression and increased by knockdown, and adavosertib was synergistic with topoisomerase I inhibitor DXd. In vivo, the T-DXd + adavosertib combination significantly increased γH2AX and antitumor activity in HER2 low, cyclin E amplified gastroesophageal cancer PDX models and prolonged event-free survival (EFS) in a HER2-overexpressing gastroesophageal cancer model. T-DXd + adavosertib treatment also increased EFS in other HER2-expressing tumor types, including a T-DXd-treated colon cancer model.

CONCLUSIONS

We provide rationale for combining T-DXd with adavosertib in HER2-expressing cancers, especially with co-occuring CCNE1 amplifications. See related commentary by Rolfo et al., p. 4317.

Value of Antibody Drug Conjugates for Gynecological Cancers: A Modern Appraisal Following Recent FDA Approvals

Antibody drug conjugates (ADCs) are a new class of targeted anti-cancer therapies that combine a monoclonal tumor surface receptor-targeting antibody with a highly cytotoxic molecule payload. They enable delivery of cytotoxic therapy more directly to tumor cells and minimize delivery to healthy tissues. This review summarizes the existing literature about ADC therapies approved for use in gynecologic malignancies, relevant preclinical studies, as well as ongoing clinical trials.

HER2 Oncogene as Molecular Target in Uterine Serous Carcinoma and Uterine Carcinosarcoma

Uterine serous carcinoma (USC) and uterine carcinosarcoma (UCS) are two rare histologic variants of uterine carcinoma, with distinct molecular profiles and aggressive metastatic potential. As the effectivity of traditional platinum-based chemotherapy for USC and UCS is low, and there are high rates of resistance and recurrence, the development of novel targeted therapeutics is needed. Human epidermal growth factor receptor 2 (HER2) has proven to be an oncogene of increasing interest in these cancers, as HER2 protein overexpression and/or c-ERBB2 gene amplification ranges from ~30 to 35% in USC, and between ~15 and 20% in UCS. This review summarizes the existing clinical and preclinical evidence, as well as ongoing clinical trials of HER2-targeting therapeutics, and identifies potential areas of further development and inquiry.

Trastuzumab deruxtecan in recurrent uterine serous carcinoma resistant to trastuzmab based-chemotherapy

Background

Treatment of uterine serous carcinoma (USC) is challenging; effective treatment options for metastatic and recurrent disease are needed.

Case

A 68-year-old woman with recurrent, metastatic, USC overexpressing HER2/neu experienced durable response to the antibody drug conjugate (ADC) trastuzumab-deruxtecan (T-DXd), after failing multiple standard and experimental treatments targeting HER2/neu. She experienced a significant reduction in disease burden, disappearance of metastatic back bone pain as well as normalization of CA-125 quickly after starting treatment. Her disease continued to show response to treatment over 5 months and 7 cycles of T-DXd therapy. She did not experience any dose-limiting side effects and tolerated treatment with 5.4 mg/kg T-DXd without issue.

Conclusion

T-DXd may present a new treatment option for chemotherapy-resistant uterine serous carcinoma.