Efficacy and safety of HER2-targeted inhibitors for metastatic colorectal cancer with HER2-amplified: A meta-analysis

Phase II Study of Irinotecan, Trifluridine/tipiracil (TAS-102) plus Bevacizumab as a Later-line Therapy for Patients with Metastatic Colorectal Cancer (mCRC): a prospective single-center explorative study

PURPOSE

To explore the efficacy and safety of the combination of irinotecan, trifluridine/tipiracil (TAS-102), and bevacizumab in a later-line setting for metastatic colorectal cancer (mCRC) patients.

PATIENTS AND METHODS

This was a single-center, phase II trial. The mCRC patients who are refractory to standard first-line and second-line treatment are eligible. Patients who previously received irinotecan while progressing during maintenance therapy are also eligible. The primary endpoint was the objective response rate (ORR).

RESULTS

Between August 1, 2022, and September 30, 2023, 35 patients were enrolled, and 31 of them were evaluable for efficacy. The ORR was 25.8% (8/31), and the disease control rate (DCR) was 93.5% (29/31). As of April 30, 2024, the median progression-free survival (PFS) was 9.2 months (95% CI 6.285-12.115), whereas the median overall survival (OS) was not reached with the 1-year OS rate of 73.5%. The most common grade 3/4 treatment-related adverse events were neutropenia (34.3%), anemia (17.1%), and thrombocytopenia (8.6%).

CONCLUSION

Irinotecan, TAS-102 plus bevacizumab regimen preliminarily demonstrated promising efficacy with tolerable toxicity for mCRC patients as later-line treatment. This regimen warrants further exploration in refractory mCRC patients.

Molecular mechanisms of HER2-targeted therapy and strategies to overcome the drug resistance in colorectal cancer

HER2 amplification is one of the mechanisms that induce drug resistance to anti-EGFR therapy in colorectal cancer. In recent years, data from several randomized clinical trials show that anti-HER2 therapies improved the prognosis of patients with HER2-positive colorectal cancer. These results indicate that HER2 is a promising therapeutic target in advanced colorectal cancer. Despite the anti-HER2 therapies including monoclonal antibodies, tyrosine kinase inhibitors, and antibody-drug conjugates improving the outcomes, less than 30 % of the patients achieve objective response and eventually have drug resistance. It is necessary to explore the primary and secondary mechanisms for the resistance to anti-HER2 therapies, which will pave the way to overcome the drug resistance. Several studies have reported the potential mechanisms for the resistance to anti-HER2 therapies. In this review, we present a comprehensive overview of the recent advances in clinical research, mechanisms of treatment resistance, and strategies for reversing resistance in HER2-positive colorectal cancer patients.

Clinical Phase I Study of TAS102/Irinotecan/Bevacizumab Combination Therapy in Japanese Patients With Unresectable Metastatic Colorectal Cancer (mCRC)

BACKGROUND

In this phase I study, we aimed to examine the safety of a triple combination (TAS-102/irinotecan/bevacizumab) therapy in patients with previously treated metastatic colorectal cancer (mCRC).

METHODS

In the TAS-102 dose-escalation phase, we determined dose-limiting toxicity (DLT), estimated the maximum tolerated dose (MTD), and determined the recommended dose (RD); in the expansion phase, we evaluated safety. The RD was administered in advance for 10 patients. The TAS-102 dose was increased to 25-35 mg/m2 and administered orally twice on days 1-5 and 8-12. Irinotecan (100 mg/m2) and bevacizumab (5 mg/m2) were administered on days 1 and 15 of the treatment, respectively.

RESULTS

Fifteen patients were enrolled in dose-escalation Levels 1-3, and ten in the expansion phase. A 30 mg/m2 TAS-102 dose at Level 2 was administered to three patients, with one presenting grade 4 neutropenia. A 35 mg/m2 TAS-102 dose at Level 3 was administered to five patients, with three patients presenting grade 4 neutropenia and grade 3 DLTs. We added three patients at Level 2 and set the MTD at 30 mg/m2, with no DLTs. The RD was fixed at 25 mg/m2, with no DLTs (N = 10) or treatment-related deaths. One patient showed complete response at Level 2, four presented partial response, and eleven individuals maintained stable disease for over four months. The median progression-free survival duration was 7.6 months, while the median overall survival period was 16.9 months.

CONCLUSION

The TAS-102/irinotecan/bevacizumab combination therapy was safe, effective, and well-tolerated in patients previously treated with mCRC.

Molecular targeted therapy for metastatic colorectal cancer: current and evolving approaches

Colorectal cancer (CRC) represents 10% of all cancer types, making it the third leading cause of cancer-related deaths globally. Metastasis is the primary factor causing mortality in CRC patients. Approximately 22% of CRC-related deaths have metastasis present at diagnosis, with approximately 70% of these cases recurring. Recently, with the application of novel targeted drugs, targeted therapy has become the first-line option for individualized and comprehensive treatment of CRC. The management of these patients remains a significant medical challenge. The most prevalent targeted therapies for CRC in clinical practice focus on anti-vascular endothelial growth factor and its receptor, epidermal growth factor receptor (EGFR), and multi-target kinase inhibitors. In the wake of advancements in precision diagnosis and widespread adoption of second-generation sequencing (NGS) technology, rare targets such as BRAF V600E mutation, KRAS mutation, HER2 overexpression/amplification, and MSI-H/dMMR in metastatic colorectal cancer (mCRC) are increasingly being discovered. Simultaneously, new therapeutic drugs targeting these mutations are being actively investigated. This article reviews the progress in clinical research for developing targeted therapeutics for CRC, in light of advances in precision medicine and discovery of new molecular target drugs.

The efficacy and safety of trastuzumab deruxtecan (T-DXd) in HER2-expressing solid tumours: a single-arm meta-analysis

OBJECTIVE

We performed a meta-analysis to assess the efficacy and safety of T-DXd in the treatment of HER2-expressing solid tumours.

METHODS

We systematically searched PubMed, Web of Science, Embase and the Cochrane Library and collected studies published before March 17, 2023, on T-DXd for HER2-expressing tumours for a meta-analysis. We performed a subgroup analysis based on the different cancer types and the doses used.

RESULTS

There were 11 studies including 1349 HER2-expressing patients in this meta-analysis. The pooled ORR was 47.91%, and the pooled DCR was 87.01%. The mPFS and mOS combined were 9.63 and 10.71 months, respectively. The most common adverse reactions in grades 1-2 were decreased appetite (49.3%) and vomiting (43.0%). The netropemia (31.2%) and leukopenia (31.2%) were the most common grade 3 and higher adverse reactions. Subgroup analysis showed that breast cancer had the best ORR and DCR, with 66.96 and 96.52%, respectively.

CONCLUSIONS

Overall, the efficacy of T-DXd in treating HER2-expressing solid tumours is encouraging, especially breast and non-small cell lung cancers, and has an acceptable safety profile. However, concerns remain about potentially serious treatment adverse events (e.g. interstitial lung disease/pneumonia). More well-designed, large-scale randomized controlled trials are needed to demonstrate our study.