Combined therapy of dabrafenib and an anti-HER2 antibody-drug conjugate for advanced BRAF-mutant melanoma

BACKGROUND

Melanoma is the most lethal skin cancer characterized by its high metastatic potential. In the past decade, targeted and immunotherapy have brought revolutionary survival benefits to patients with advanced and metastatic melanoma, but these treatment responses are also heterogeneous and/or do not achieve durable responses. Therefore, novel therapeutic strategies for improving outcomes remain an unmet clinical need. The aim of this study was to evaluate the therapeutic potential and underlying molecular mechanisms of RC48, a novel HER2-target antibody drug conjugate, either alone or in combination with dabrafenib, a V600-mutant BRAF inhibitor, for the treatment of advanced BRAF-mutant cutaneous melanoma.

METHODS

We evaluated the therapeutic efficacy of RC48, alone or in combination with dabrafenib, in BRAF-mutant cutaneous melanoma cell lines and cell-derived xenograft (CDX) models. We also conducted signaling pathways analysis and global mRNA sequencing to explore mechanisms underlying the synergistic effect of the combination therapy.

RESULTS

Our results revealed the expression of membrane-localized HER2 in melanoma cells. RC48 effectively targeted and inhibited the growth of HER2-positive human melanoma cell lines and corresponding CDX models. When used RC48 and dabrafenib synergically induced tumor regression together in human BRAF-mutant melanoma cell lines and CDX models. Mechanically, our results demonstrated that the combination therapy induced apoptosis and cell cycle arrest while suppressing cell motility in vitro. Furthermore, global RNA sequencing analysis demonstrated that the combination treatment led to the downregulation of several key signaling pathways, including the PI3K-AKT pathway, MAPK pathway, AMPK pathway, and FOXO pathway.

CONCLUSION

These findings establish a preclinical foundation for the combined use of an anti-HER2 drug conjugate and a BRAF inhibitor in the treatment of BRAF-mutant cutaneous melanoma.

Combined inhibition of HER2 and VEGFR synergistically improves therapeutic efficacy via PI3K-AKT pathway in advanced ovarian cancer

BACKGROUND

Ovarian cancer (OC) is a prevalent malignancy in the female reproductive system, and developing effective targeted therapies for this disease remains challenging. The aim of this study was to use clinically-relevant OC models to evaluate the therapeutic effectiveness of RC48, an antibody-drug conjugate (ADC) targeting HER2, either alone or in combination with the VEGFR inhibitor Cediranib Maleate (CM), for the treatment of advanced OC.

METHODS

OC tumor specimens and cell lines were analyzed to determine HER2 and VEGFR expression by Western blot, immunocytochemistry and immunofluorescence. Moreover, the OC cell lines, cell-derived xenograft (CDX) and patient-derived xenograft (PDX) models were treated with RC48 and/or CM and then subjected to cell proliferation, viability, apoptosis, and tumor growth analyses to evaluate the feasibility of combination therapy for OC both in vitro and in vivo. Additionally, RNA-Seq was performed to investigate the critical mechanism underlying the combination therapy of RC48 and CM.

RESULTS

Our results demonstrated that RC48 alone effectively targeted and inhibited the growth of HER2-positive OC tumors in both cell lines and PDX models. Furthermore, the combination of RC48 and CM synergistically induced tumor regression in human OC cell lines, as well as CDX and PDX models. Mechanistically, we observed that the combination treatment inhibited the growth of OC cells involved inducing apoptosis and suppressing cell motility. RNA-seq analysis provided further mechanistic insights and revealed that co-administration of RC48 and CM downregulated multiple cancer-related pathways, including the AKT/mTOR pathway, cell cycle, and cell proliferation. Notably, our data further confirmed that the PI3K-AKT pathway played a key role in the inhibition of proliferation triggered by combinational treatment of RC48 and CM in OC cells.

CONCLUSIONS

These findings provide a preclinical framework supporting the potential of dual targeting HER2 and VEGFR as a promising therapeutic strategy to improve outcomes in patients with OC.

Combination treatment with anti-HER2 therapeutic antibody RC48, PD-1 inhibitor, radiotherapy, and granulocyte macrophage-colony stimulating factor (GM-CSF) in patient with metastatic gastric cancer: a case report

HER2 overexpression/amplification is a prevalent driver in various types of cancer, including gastric cancer (GC). Limited options are available for patients with HER2-positive metastatic gastric cancer, particularly those who do not respond to the standard therapy of HER2 antibody trastuzumab combined with chemotherapy. Previous research suggests that combining a PD-1 inhibitor with radiotherapy and granulocyte macrophage-colony stimulating factor (PRaG regimen) may enhance the antitumor effects in patients with chemotherapy-resistant metastatic solid tumors. In this case study, we presented a potential treatment strategy of a patient having HER2-positive and PD-L1-negative gastric adenocarcinoma. The patient showed rapid tumor progression even after surgery and multiple trastuzumab plus chemotherapy treatments. To address this, we employed a novel anti-HER2 antibody called RC48 in combination with PRaG regimen therapy (PRaG3.0). The patient demonstrated a positive response after two treatment cycles and achieved a progression-free survival time of 6.5 months. This case highlights the potential of four-combination therapies for treating refractory, multiorgan, HER2-positive, PD-L1-negative metastatic gastric cancer. Additionally, varying radiation doses in targeting dual foci is critical to enhance tumor immunotherapy.

Immune checkpoint inhibitors enhanced the antitumor efficacy of disitamab vedotin for patients with HER2-positive or HER2-low advanced or metastatic gastric cancer: a multicenter real-world study

BACKGROUND

Novel ADC drugs provide a new therapeutic strategy for gastric cancer.The present study aimed to analyze the clinical efficacy and drug toxicities of disitamab vedotin (RC48) plus immune checkpoint inhibitors(ICIs) and RC48 as third-line therapies and beyond for advanced and metastatic gastric cancer patients.

METHODS

This was an observational multicenter real-world study.From August 2021 to January 2022,patients with HER2-positive or HER2-low advanced and metastatic gastric cancer and failed from two or more lines of prior therapy were enrolled and treated with RC48 plus ICIs or RC48. In this study, progression free survival(PFS) was the primary end point. Other evaluation indicators were objective response rate(ORR),disease control rate(DCR),overall survival(OS) and drug toxicities.

RESULTS

45 patients were enrolled,of which 25 patients received RC48 plus ICIs,20 patients received RC48.Patients who received RC48 plus ICIs obtained better ORR (36.0% vs. 10.0%, P = 0.044) and DCR (80.0% vs. 50.0%, P = 0.034) compared with RC48,and simultaneously,the median PFS in RC48 plus ICIs group were superior to RC48 group(6.2 m vs. 3.9 m).The median OS was not reached.No statistically differences were found between HER2-positive and HER2-low group with respect to ORR (27.3% vs. 16.7%, P = 0.464),DCR (66.7% vs. 66.7%, P = 1.000),median PFS(5.7 m vs. 4.3 m, P = 0.299).The most common adverse events (AEs) were decreased white blood count,decreased neutrophil count,fatigue,hypoaesthesia and alopecia.Grade 3-4 AEs occurred in 7(35.0%) patients of RC48 group and 10(40.0%) patients of RC48 plus ICIs group,respectively.

CONCLUSION

Compared with RC48 monotherapy, ICIs plus RC48 demonstrated superior third-line and beyond therapeutic efficacy for HER2-positive or HER2-low advanced and metastatic gastric cancer patients with manageable safety.

Disitamab Vedotin (RC48) combined with bevacizumab for treatment of HR-negative/HER2-positive metastatic breast cancer with liver and brain involvement: A case report

Background

The overexpression of human epidermal growth factor receptor 2 (HER2) is strongly correlated with an elevated risk of developing distant metastases, particularly brain metastases, in breast cancer (BC) cases. RC48 (also known as Disitamab vedotin), represents a promising antibody-drug conjugate (ADC), that comprises three well-defined components: hertuzumab against the prominent tumor target-HER2, monomethyl auristatin E (MMAE) and a cleavable linker. Preclinical studies have demonstrated its robust antitumor activity in BC patient-derived xenograft models with HER2-positive or HER2-low expression. Additionally, antiangiogenic drugs like bevacizumab have shown potential efficacy on advanced BC via inhibiting pathological neovascularizationits.

Case presentation

Here, we will share our experience in treating a 49-year-old woman initially diagnosed with stage IV breast cancer characterized by hormone receptor (HR)-negativity and HER2-positivity. This complex case entailed brain and liver metastases, and the patient exhibited resistance to various HER2-targeted treatment regimens. Finally, the patient received RC48 plus bevacizumab as the advanced forth-line treatment, which was well tolerated with no observed toxicities. Subsequent radiological assessments revealed remarkable regression in the brain metastatic lesions, classified as having partial response based on the RECIST 1.1 system. The period of progression-free survival (PFS) was 7 months.

Conclusion

The present study underscores the efficacy of systemic treatment with RC48 in conjunction, showcasing substantial enhancement in both radiographic indicators and clinical symptomatology among patients with brain metastatic breast cancer (BMBC). More specifically, the sequential application of ADCs in combination with antiangiogenics presents a novel avenue for advancing the treatment landscape of metastatic BC.

Disitamab vedotin in combination with immune checkpoint inhibitors for locally and locally advanced bladder urothelial carcinoma: a two-center's real-world study

Objective: Our study aims to assess the effectiveness and safety profile of Disitamab Vedotin (DV, RC48-ADC), an innovative humanized anti-HER2 antibody conjugated with tubulin-disrupting antimitotic drug monomethyl auristatin E (MMAE) via a cleavable peptide linker. This treatment combined immune checkpoint inhibitors as part of the bladder sparing approach for selected patients suffering from locally and locally advanced bladder urothelial carcinoma. Patients and methods: We conducted a two-center, real-world study involving locally advanced urothelial carcinoma (UC) patients. Patients were classified based on HER2 expression (IHC 3+/2+/1+) or lack of HER2 expression (IHC 0). The primary endpoint was the objective response rate (ORR), assessed by the investigator following the criteria of RECIST V1.1. Secondary endpoints encompassed the pathological complete response rate (pCR), pathological partial response rate (pPR), and pathological stable disease (pSD), along with recurrence-free survival (RFS), the pathological downstaging rate, and the safety profile of the treatment. Results: In this study, nine patients were enrolled, with a median follow-up duration of 12.0 months. The overall confirmed ORR was 88.9%, Five patients achieved a complete response (CR), and three patients achieved a partial response (PR). The radiological complete response (rCR) aligned perfectly with pCR. The median radiological progression-free survival (rPFS) spanned 12.0 months (range from 8.0 to 17.0 months). One patient diagnosed with disease progression (PD) underwent a radical cystectomy. The pathological stage evolved from T2N0M0 to T3aN2M0, followed by adjuvant chemotherapy with a gemcitabine-cisplatin (GC) combination radiotherapy. At the 9-month follow-up, neither recurrence nor metastasis was observed. The rate and intensity of complications were manageable among these patients, with no evidence of grade 4 and 5 adverse events. Conclusion: The combination of DV and PD-1 demonstrated considerable activity in the objective response rate (ORR) in patients with HER2 IHC 0/1+/2+/3+ muscle-invasive bladder cancer (MIBC), along with the longest reported median radiological progression-free survival (rPFS) to date. With an extended duration of treatment, the safety profile of DV plus PD-1 was also confirmed to be manageable.

HER2-targeting antibody-drug conjugate RC48 alone or in combination with immunotherapy for locally advanced or metastatic urothelial carcinoma: a multicenter, real-world study

BACKGROUND

Phase II trials showed the efficacy of anti-HER2 RC48-ADC (disitamab vedotin) for HER2-positive metastatic urothelial carcinoma (UC). This study evaluated RC48 alone verses in combination with immunotherapy for locally advanced or metastatic UC using real-world data.

METHODS

This retrospective, multicenter, real-world study included patients with locally advanced or metastatic UC who received RC48 in five hospitals in China between July 2021 and April 2022. The outcomes were progression-free survival (PFS), overall survival (OS), objective response rate (ORR), disease control rate (DCR), and adverse events.

RESULTS

Thirty-six patients were included. The patients were 47-87 years, and 26 (72.2%) were male. Eighteen patients received RC48 alone, and 18 received RC48 combined with a programmed death-1 antibody. The median PFS was 5.4 months. The median OS was not reached. The 6-month and 1-year PFS rates were 38.8% and 15.5%, respectively. The 1-year OS rate was 79.6%. Fourteen (38.9%) patients achieved a partial response, and the ORR was 38.9%. Eleven patients had stable disease, and the DCR was 69.4%. The median PFS for patients who received RC48 combined with immunotherapy and those who received RC48 alone was 8.5 and 5.4 months, respectively. The main treatment-related adverse events included anemia, hypoesthesia, fatigue, and elevated transaminase. No treatment-related death occurred.

CONCLUSION

RC48 alone or combined with immunotherapy might benefit patients with locally advanced or metastatic UC, regardless of impaired renal function.

Efficacy and safety of a novel anti-HER2 therapeutic antibody RC48 in patients with HER2-overexpressing, locally advanced or metastatic gastric or gastroesophageal junction cancer: a single-arm phase II study

Background

Current treatment options for human epidermal growth factor receptor 2 (HER2)‐overexpressing gastric cancer at third‐line have shown limited clinical benefit. Further, there is no specific treatment for HER2 immunohistochemistry (IHC) 2+ and fluorescence in‐situ hybridization‐negative patients. Here, we report the efficacy and safety of a novel anti‐HER2 antibody RC48 for patients with HER2‐overexpressing, advanced gastric or gastroesophageal junction cancer.

Methods

Patients with HER2‐overexpressing (IHC 2+ or 3+), locally advanced or metastatic gastric or gastroesophageal junction cancer who were under at least second‐line therapy were eligible and received RC48 2.5 mg/kg alone every 2 weeks. The primary endpoint was the objective response rate (ORR) assessed by an independent review committee. Secondary endpoints included progression‐free survival (PFS), overall survival (OS), duration of response, time to progression, disease control rate, and safety.

Results

Of 179 patients screened, 125 were eligible and received RC48 treatment. The ORR was 24.8% (95% confidence interval [CI]: 17.5%‐33.3%). The median PFS and OS were 4.1 months (95% CI: 3.7‐4.9 months) and 7.9 months (95% CI: 6.7‐9.9 months), respectively. The most frequently reported adverse events were decreased white blood cell count (53.6%), asthenia (53.6%), hair loss (53.6%), decreased neutrophil count (52.0%), anemia (49.6%), and increased aspartate aminotransferase level (43.2%). Serious adverse events (SAEs) occurred in 45 (36.0%) patients, and RC48‐related SAEs were mainly decreased neutrophil count (3.2%). Seven patients had adverse events that led to death were not RC48‐related.

Conclusions

RC48 showed promising activity with manageable safety, suggesting potential application in patients with HER2‐overexpressing, advanced gastric or gastroesophageal junction cancer who have previously received at least two lines of chemotherapy.