CF33-hNIS-anti-PD-L1 oncolytic virus followed by trastuzumab-deruxtecan in a patient with metastatic triple negative breast cancer: a case study.

Prognosis of metastatic triple negative breast cancer (mTNBC) remains poor despite recent advances in therapeutic options. Trastuzumab deruxtecan (T-DXd) has shown promising efficacy in patients with human epidermal growth factor receptor 2 (HER2)-low breast cancer, which is defined by immunohistochemistry (IHC) 1+ or 2+ and lack of HER2 amplification by fluorescence in situ hybridization (FISH) testing. The purpose of the study is to evaluate the safety and initial evidence of efficacy of intratumoral administration of CF33-hNIS-anti-PD-L1 (CHECKvacc) against mTNBC. Oncolytic virus CHECKvacc intratumoral injection is currently undergoing investigation in patients with mTNBC as a single agent (NCT05081492). The patient was enrolled on the clinical trial CHECKvacc for the Treatment of Metastatic Triple Negative Breast Cancer, received a single dose of CHECKvacc, and discontinued the study due to lack of immediate response. We report a case of a patient with mTNBC who was heavily pretreated and presented with extensive dermal metastasis. Two dermal metastasis biopsies in 2021 showed HER2 0 by IHC. The patient received a single dose of CHECKvacc and discontinued the study due to lack of immediate response. Twenty-five days later, the patient received treatment with T-DXd, and her tumor regressed significantly. The patient's disease-free survival was 10 months (December 2021-October 2022). The sequential treatment with intratumoral injection of CHECKvacc followed by T-DXd may have significant clinical activity in select patients with heavily pretreated mTNBC. ClinicalTrials.gov NCT05081492.

Immunogenicity and efficacy of pembrolizumab and doxorubicin in a phase I trial for patients with metastatic triple-negative breast cancer.

Currently there is a limited understanding for the optimal combination of immune checkpoint inhibitor and chemotherapy for patients with metastatic triple-negative breast cancer (mTNBC). Here we evaluate the safety, efficacy, and immunogenicity of a phase I trial for patients with mTNBC treated with pembrolizumab plus doxorubicin. Patients without prior anthracycline use and 0-2 lines of prior systemic chemotherapies received pembrolizumab and doxorubicin every 3 weeks for 6 cycles followed by pembrolizumab maintenance until disease progression or intolerance. The primary objectives were safety and objective response rate per RECIST 1.1. Best responses included one complete response (CR), five partial responses (PR), two stable disease (SD), and one progression of disease (PD). Overall response rate was 67% (95% CI 13.7%, 78.8%) and clinical benefit rate at 6 months was 56% (95% CI 21.2%, 86.3%). Median PFS was 5.2 months (95% CI 4.7, NA); median OS was 15.6 months (95% CI 13.3, NA). Grade 3-4 AEs per CTCAE 4.0 were neutropenia n = 4/10 (40%), leukopenia n = 2/10 (20%), lymphopenia n = 2/10 (20%), fatigue n = 2/10 (20%), and oral mucositis n = 1/10 (10%). Immune correlates showed increased frequencies of circulating CD3 + T cells (p = 0.03) from pre-treatment to cycle 2 day 1 (C2D1). An expansion of a proliferative exhausted-like PD-1 + CD8 + T cell population was identified in 8/9 patients, and exhausted CD8 + T cells were significantly expanded from pre-treatment to C2D1 in the patient with CR (p = 0.01). In summary, anthracycline-naïve patients with mTNBC treated with the combination of pembrolizumab and doxorubicin showed an encouraging response rate and robust T cell response dynamics.Trial registration: NCT02648477.

Phase I Trial of Ipatasertib Plus Carboplatin, Carboplatin/Paclitaxel, or Capecitabine and Atezolizumab in Metastatic Triple-Negative Breast Cancer.

BACKGROUND: This trial evaluated the safety and efficacy of ipatasertib in combination with carboplatin, carboplatin/paclitaxel, or capecitabine/atezolizumab in patients with metastatic triple-negative breast cancer (mTNBC). METHODS: Eligibility criteria were mTNBC, RECIST 1.1 measurable disease, no prior use of platinum for metastatic disease (Arms A and B), and no prior exposure to immune checkpoint inhibitor (Arm C). Primary endpoints were safety and RP2D. Secondary endpoints were progression-free survival (PFS), response rate, and overall survival. RESULTS: RP2D for Arm A (n = 10) was ipatasertib 300 mg daily, carboplatin AUC2, and paclitaxel 80 mg m-2 days 1, 8, and 15 every 28 days. RP2D for Arm B (n = 12) was ipatasertib 400 mg daily and carboplatin AUC2 days 1, 8, and 15 every 28 days. RP2D for Arm C (n = 6) was likely ipatasertib 300 mg 21 days on 7 days off, capecitabine 750 mg m-2, twice a day, 7 days on 7 days off, and atezolizumab 840 mg days 1 and 15 every 28 days. The most common (≥10%) grade 3-4 AEs at RP2D for Arm A (N = 7 at RP2D) were neutropenia (29%), diarrhea (14%), oral mucositis (14%), and neuropathy (14%); Arm B had diarrhea (17%) and lymphopenia (25%); and Arm C had anemia, fatigue, cognitive disturbance, and maculopapular rash (17% each). Overall responses at RP2D were 29% Arm A, 25% Arm B, and 33% Arm C. PFS was 4.8, 3.9, and 8.2 months for patients on Arms A, B, and C, respectively. CONCLUSIONS: Continuous dosing of ipatasertib with chemotherapy was safe and well-tolerated. Further study is warranted in understanding the role of AKT inhibition in treatment of TNBCs. TRIAL REGISTRATION: NCT03853707.

Phase 2 prospective open label study of neoadjuvant nab-paclitaxel, trastuzumab, and pertuzumab in patients with HER2-positive primary breast cancer.

BACKGROUND: The objective of this study was to evaluate the safety and efficacy of nab-paclitaxel, trastuzumab, and pertuzumab as neoadjuvant therapy (NAT) in patients with human epidermal growth factor receptor 2 HER2+ breast cancer (HER2+ BC) to determine pathologic complete response (pCR), invasive disease-free survival (iDFS), and overall survival. METHODS: Forty-five patients with HER2+ BC Stages II-III were to be enrolled from 2013 to 2017. Patients were treated with weekly nab-paclitaxel (100 mg/m2 intravenously), weekly trastuzumab (4 mg/kg loading dose, then 2 mg/kg), and six cycles of pertuzumab (840 mg loading dose, then 420 mg intravenously day 1 every 21 days). RESULTS: Median follow-up was 60 months (95% CI, 32.3-55.6) and pCR was 29/45 (64%). The 5-year iDFS for patients who achieved pCR (N = 29) was 96.3% (95% CI, 76.5-99.5) and non-pCR patients (N = 16) was 74.3% (95% CI, 39.1-91.0). The 5-year overall survival (N = 45) was 94.1% (95% CI, 77.6-98.5). Based on hormonal status, the 5-year iDFS for HR+ pCR patients (N = 14) was 92.3% (95% CI, 56.6-98.9) and for HR- (N = 15) was 100% (p = .3). CONCLUSIONS: This anthracycline/carboplatin-free regimen with nab-paclitaxel achieved a pCR rate of 64% in patients with HER2+ BC. The 5-year iDFS in patients with and without pCR was 96.3% and 74.3%, respectively. The pCR rate is comparable with docetaxel, carboplatin, trastuzumab, and pertuzumab therapy in the NAT setting, but with fewer treatment-associated toxicities. This finding suggests the possibility of safe avoidance of anthracyclines and carboplatin as components of NAT in patients with HER2+ BC.

Phase II Study Combining Pembrolizumab with Aromatase Inhibitor in Patients with Metastatic Hormone Receptor Positive Breast Cancer.

This study investigated the safety and antitumor activity of aromatase inhibitors (AI) with immune checkpoint inhibitor (ICI) pembrolizumab in patients with hormone receptor positive (HR+) human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC) in a phase II study with a safety lead-in (NCT02648477). Patients received pembrolizumab plus AI up to 2 years or until confirmed progression or unacceptable toxicity. Key eligibility criteria were HR+ HER2- MBC; RECIST v1.1 measurable disease; adequate organ function; and ECOG 0-1. Primary endpoints were safety and overall response rate. A 3-at-risk design was used for the safety lead-in with a targeted accrual of 20 patients. Grade 2 adverse events (AEs) included 35% fatigue, 20% rash, and 10% hot flashes. Grade 3 immune-related AEs (irAEs) related to pembrolizumab included 5% elevated AST/ALT, 5% rash, and 5% lymphopenia. Two (10%) patients had partial responses, three (15%) had stable disease, and 15 (75%) had progression of disease. Median progression-free survival was 1.8 months (95% CI 1.6, 2.6), median overall survival was 17.2 months (95% CI 9.4, NA), and median follow-up time was 40.1 months (range 31.3-46.8 months). The combination was well tolerated, but clinical activity was comparable to AI alone.

Genomic Markers of CDK 4/6 Inhibitor Resistance in Hormone Receptor Positive Metastatic Breast Cancer.

Cyclin-dependent kinase 4/6 inhibitors are the standard of care for hormone receptor-positive metastatic breast cancer. This retrospective study reports on genomic biomarkers of CDK 4/6i resistance utilizing genomic data acquired through routine clinical practice. Patients with HR+ MBC treated with palbociclib, ribociclib, or abemaciclib and antiestrogen therapy were identified. Patients were grouped into early (<6 months); intermediate (6−24 months for 0−1 lines; 6−9 months for ≥2 lines); or late progressors (>24 months for 0−1 lines; >9 months PFS for ≥2 lines). NGS and RNA sequencing data were analyzed in association with PFS, and survival analysis was stratified by prior lines of chemotherapy. A total of 795 patients with HR+ MBC treated with CDK 4/6i were identified. Of these, 144 (18%) patients had genomic data and 29 (3.6%) had RNA data. Among the 109 patients who received CDK4/6i as 1st- or 2nd-line therapy, 17 genes showed associations with PFS (p-value ≤ 0.15 and HR ≥ 1.5 or HR < 0.5). Whole transcriptome RNAseq was analyzed for 24/109 (22%) patients with 0−1 prior lines of therapy and 56 genes associated with PFS (HR ≥ 4 or HR ≤ 0.25 and FDR ≤ 0.15). In this retrospective analysis, genomic biomarkers including FGFR1 amplification, PTEN loss, and DNA repair pathway gene mutations showed significant associations with shorter PFS for patients receiving CDK4/6 inhibitor therapy.