Trastuzumab deruxtecan in patients with HER2-positive advanced colorectal cancer (DESTINY-CRC02): primary results from a multicentre, randomised, phase 2 trial.

BACKGROUND: Trastuzumab deruxtecan has shown encouraging activity in patients with treatment-refractory HER2-positive, RAS wild-type and BRAF wild-type metastatic colorectal cancer. Dose optimisation and further antitumour assessments in patients with RAS mutations and those with previous anti-HER2 therapy are warranted. We aimed to evaluate two doses of trastuzumab deruxtecan (5·4 mg/kg and 6·4 mg/kg) to establish the recommended dose in patients with pretreated HER2-positive, RAS wild-type or mutant metastatic colorectal cancer. METHODS: DESTINY-CRC02 was a multicentre, randomised, two-stage, two-arm, phase 2 study done in 53 research hospitals and medical centres in Australia, Belgium, France, Italy, Japan, South Korea, Spain, Taiwan, the UK, and the USA. Eligible patients were aged 18 years and older or 20 years and older (depending on region) with pretreated pathologically documented, unresectable, recurrent, or metastatic HER2-positive, and RAS wild-type or mutant colorectal cancer. Patients were required to have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 and have received previous chemotherapy, and anti-EGFR, anti-VEGF, or anti-PD-L1 therapy, if clinically indicated. In stage 1, patients were randomly assigned (1:1), via a secure interactive response technology system, to receive 5·4 mg/kg or 6·4 mg/kg trastuzumab deruxtecan administered intravenously every 21 days. Stratification factors were ECOG performance status, HER2 status, and RAS status. In stage 2, patients were assigned into the 5·4 mg/kg treatment group only. The primary endpoint was confirmed objective response rate by blinded independent central review, assessed in all patients for whom treatment was assigned (full analysis set). Safety was assessed in all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, NCT04744831, and is ongoing (not recruiting). FINDINGS: Between March 5, 2021, and March 29, 2022, 135 patients were centrally screened, 122 of whom were enrolled. In stage 1, 40 patients each were randomly assigned to receive trastuzumab deruxtecan 5·4 mg/kg and 6·4 mg/kg. In stage 2, an additional 42 patients were enrolled in the 5·4 mg/kg group. 64 (52%) participants were male and 58 (48%) were female. The median duration of follow-up was 8·9 months (IQR 6·7-10·5) in the 5·4 mg/kg group and 10·3 months (5·9-12·7) in the 6·4 mg/kg group. The confirmed objective response rate by blinded independent central review was 37·8% (31/82 [95% CI 27·3-49·2]) in the 5·4 mg/kg group and 27·5% (11/40 [14·6-43·9]) in the 6·4 mg/kg group. 34 (41%) of 83 patients in the 5·4 mg/kg group and 19 (49%) of 39 in the 6·4 mg/kg group had grade 3 or worse drug-related treatment-emergent adverse events. The most common grade 3 or worse drug-related treatment-emergent adverse events were neutrophil count decreased (13 [16%] of 83 patients), anaemia (six [7%]), nausea (six [7%]), and white blood cell count decreased (five [6%]) in the 5·4 mg/kg group; and were neutrophil count decreased (10 [26%] of 39 patients), anaemia (eight [21%]), platelet count decreased (four [10%]), and white blood cell count decreased (four [10%]) in the 6·4 mg/kg group. Drug-related serious adverse events occurred in 11 (13%) of 83 patients in the 5·4 mg/kg group and six (15%) of 39 patients in the 6·4 mg/kg group; the most common in the 5·4 mg/kg group was nausea (three [4%] patients) and the most common in the 6·4 mg/kg group were fatigue (two [5%] patients), neutropenia (two [5%]), and thrombocytopenia (two [5%]). A drug-related treatment-emergent adverse event related to death occurred in one (1%) patient in the 5·4 mg/kg group (due to hepatic failure). Adjudicated drug-related interstitial lung disease or pneumonitis events were observed in seven (8%) patients in the 5·4 mg/kg group (all grade 1 or 2) and in five (13%) patients in the 6·4 mg/kg group (four grade 1 or 2; one grade 5). INTERPRETATION: The promising antitumour activity and favourable safety profile support trastuzumab deruxtecan 5·4 mg/kg as the optimal single-agent dose for patients with pretreated HER2-positive metastatic colorectal cancer, including those with RAS mutations, previous anti-HER2 therapy, or both. FUNDING: Daiichi Sankyo and AstraZeneca.

Targeting KRAS-Mutated Gastrointestinal Malignancies with Small-Molecule Inhibitors: A New Generation of Breakthrough Therapies.

Kirsten rat sarcoma virus (KRAS) is one of the most important and frequently mutated oncogenes in cancer and the mutational prevalence is especially high in many gastrointestinal malignancies, including colorectal cancer and pancreatic ductal adenocarcinoma. The KRAS protein is a small GTPase that functions as an "on/off" switch to activate downstream signaling, mainly through the mitogen-activated protein kinase pathway. KRAS was previously considered undruggable because of biochemical constraints; however, recent breakthroughs have enabled the development of small-molecule inhibitors of KRAS G12C. These drugs were initially approved in lung cancer and have now shown substantial clinical activity in KRAS G12C-mutated pancreatic ductal adenocarcinoma as well as colorectal cancer when combined with anti-EGFR monoclonal antibodies. Early data are encouraging for other gastrointestinal cancers as well and many other combination strategies are being investigated. Several new KRAS G12C inhibitors and novel inhibitors of other KRAS alterations have recently entered the clinic. These molecules employ a variety of innovative mechanisms and have generated intense interest. These novel drugs are especially important as KRAS G12C is rare in gastrointestinal malignancies compared with other KRAS alterations, representing potentially groundbreaking advances. Soon, the rapidly evolving landscape of novel KRAS inhibitors may substantially shift the therapeutic landscape for gastrointestinal cancers and offer meaningful survival improvements.

Management of Microsatellite Instability High (MSI-H) Gastroesophageal Adenocarcinoma.

BACKGROUND: Gastroesophageal cancer is a major cause of cancer-related mortality worldwide. Treatment of both early stage and advanced disease remains highly reliant on cytotoxic chemotherapy. About 4-24% of gastroesophageal cancers are microsatellite instability high (MSI-H). The MSI-H subtype is associated with favorable prognosis, resistance to cytotoxic chemotherapy, and sensitivity to immune checkpoint inhibitors (ICI). Recent studies have demonstrated promising activity of ICIs in the MSI-H subtype, resulting in fundamental changes in the management of MSI-H gastroesophageal adenocarcinoma. PURPOSE: In this review, we discuss the prevalence, characteristics, prognosis, and management of MSI-H gastroesophageal adenocarcinoma, with a focus on recent and ongoing studies that have changed the landscape of treatment for the MSI-H subtype. We also discuss current challenges in the management of resectable and advanced MSI-H gastroesophageal cancer, including the need for more accurate biomarkers of response to ICI therapy.

Trastuzumab-Deruxtecan: Redefining HER2 as a Tumor Agnostic Biomarker.

Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate (ADC) targeting HER2-positive malignancies across various tumor types. Through its unique composition, T-DXd achieves selective payload delivery, inducing cell death and halting tumor progression. Clinical trials initially investigated T-DXd's efficacy in HER2-positive advanced or metastatic breast, gastric, lung, and colorectal cancers; however, recent results from the DESTINY-PanTumor02 trial further underscore T-DXd's versatility, prompting T-DXd's US FDA approval for HER2-positive (immunohistochemistry [IHC] 3+) solid tumors. Moreover, in addition to T-DXd's efficacy against brain metastasis, T-DXd is showing promising results in HER2-low and HER2-ultra-low metastatic breast cancer, indicating a broader population of patients who may benefit.

Racial and ethnic disparities in genomic testing among lung cancer patients: a systematic review.

BACKGROUND: Racial and ethnic disparities in genomic testing could exacerbate disparities in access to precision cancer therapies and survival-particularly in the context of lung cancer where genomic testing has been recommended for the past decade. However, prior studies assessing disparities in genomic testing have yielded mixed results. METHODS: We conducted a systemic review to examine racial and ethnic disparities in the use of genomic testing among lung cancer patients in the United States. Two comprehensive searches in PubMed, Embase, and Scopus were conducted (September 2022, May 2023). Original studies that assessed rates of genomic testing by race or ethnicity were included. Findings were narratively synthesized by outcome. RESULTS: The search yielded 2739 unique records, resulting in 18 included studies. All but 1 study were limited to patients diagnosed with non-small cell lung cancer. Diagnosis years ranged from 2007 to 2022. Of the 18 studies, 11 found statistically significant differences in the likelihood of genomic testing by race or ethnicity; in 7 of these studies, testing was lower among Black patients compared with White or Asian patients. However, many studies lacked adjustment for key covariates and included patients with unclear eligibility for testing. CONCLUSIONS: A majority of studies, though not all, observed racial and ethnic disparities in the use of genomic testing among patients with lung cancer. Heterogeneity of study results throughout a period of changing clinical guidelines suggests that minoritized populations-Black patients in particular-have faced additional barriers to genomic testing, even if not universally observed at all institutions.