Neoplasms

Skin and Connective Tissue Diseases

All Conditions

Breast Neoplasms

Breast Diseases

Skin Diseases

Antineoplastic Agents

All Drugs and Chemicals

Letrozole

Goserelin

Aromatase Inhibitors

Enzyme Inhibitors

Estrogens

Estrogen Antagonists

Estrogen Receptor Antagonists

Hormones

Hormone Antagonists

Antineoplastic Agents, Hormonal

Patients entered into this study will be given letrozole (FemarTM) in combination with ribociclib (KisqaliTM) for at least 6 months. Premenopausal women will also receive treatment with goserelin 3.6 mg s.c. every 4 weeks.

Patients will be given letrozole 2.5mg and ribociclib 600mg daily, per oral for a period of 21 days followed by 7 days of letrozole only.

Letrozole 2.5mg oral tablet; Ribociclib 600mg oral tablet

Premenopausal women will be given goserelin 3.6 mg (subcutaneous) every 4 weeks in concert with their Letrozole and Ribociclib treatment.

Jürgen Geisler, MD, PhD

Thale D JH Patrick-Brown, MSc

Patients with locally advanced (stage III) breast cancer (LABC) are characterized by a significantly worse prognosis compared to patients with primarily operable breast cancer. While neoadjuvant chemotherapy has been the first choice in this situation for several decades, recent evidence suggests that some patients may experience an extraordinary effect from neoadjuvant endocrine treatments involving aromatase inhibitors as monotherapy or in modern drug combinations.Selected LABC patients admitted for treatment will be offered combination therapy including letrozole and ribociclib. The overall goal of the project is to improve understanding of tumor responses and resistance in patients suffering from ER-positive/HER-2 negative locally advanced breast cancer, focusing on the role of the immune system including the gut microbiome.

Neoadjuvant endocrine therapy (NET) offers a good treatment option to reduce the size of large (inoperable) primary breast tumors and/or advanced axillary lymph node metastasis prior to definite surgery. For selected patients (postmenopausal women with ER-positive breast cancer), primary endocrine therapy has been shown to be as effective as standard neoadjuvant chemotherapy. It is the general opinion that aromatase inhibitors of the "third-generation" (letrozole, anastrozole, exemestane) are the preferable drugs for neoadjuvant endocrine therapy in ER-positive, postmenopausal breast cancer patients. Anastrozole, letrozole and exemestane have been shown to suppress total body aromatisation as well as plasma and tissue estrogen levels by \> 90% in vivo. All three drugs are currently used as standard care in the neoadjuvant, adjuvant and metastatic setting worldwide, including in Norway.

In 2015, a new class of anti-cancer drugs was introduced known as cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors. Following pivotal trials showing dramatic effects when combined with aromatase inhibitors or steroidal antiestrogens like fulvestrant, these compounds are now well established in distinct combinations during therapy for metastatic breast cancer. All in all, the addition of a CDK4/6 inhibitor to standard anti-hormone therapy for breast cancer doubled the time to disease progression and caused significant improvements in overall survival. Based on these findings, CDK4/6 inhibitors have also been tested in the neoadjuvant setting in clinical trials with very promising results. However, the combination of an aromatase inhibitor and a CDK4/6-inhibitor is not currently approved as standard neoadjuvant treatment for patients with locally advanced breast cancer (LABC) in Norway. Thus, the study described here will make this highly promising drug combination available for all patients who participate in this study. At the same time, the protocol will allow investigators to optimize the selection of patients benefitting from this treatment, highlight relevant biomarkers for personalized medicine and treatment, evaluate predictive markers and study the basic biology underlying treatment effects and resistance.

In recent years researchers have noted a growing body of evidence concerning the involvement of the immune system in the onset and prognosis of breast cancer both locally (in the tumor or connected tissues) and through the involvement of the immune system as a whole. Interestingly, the gastrointestinal (gut) microbiota seems to play an important role in determining whether the immune system is able to fight against several cancer types. Pre-clinical studies have shown that the microbes in the gut may influence the repertoire and activity of immune cells, such as T cells, potentially priming the immune system for cancer cell recognition and destruction. This hypothesis is supported by the finding that treatment responses to immune checkpoint inhibitors (ICIs) in a variety of cancer types is dependent on the distinct gut microbiome of an individual patient as the efficacy of the ICIs relies on the presence of cancer-recognizing T cells.

In addition, recent findings indicate that an emerging group of small molecules / targeting cancer therapies have immune altering properties. The MAPK kinase (MEK) inhibitors exemplify this by contributing to anti-tumor immunity through increasing the levels of cytotoxic T lymphocytes in preclinical model systems. Similar findings have recently been reported for both CDK4/6 inhibitors and PI3K-inhibitors. Thus, CDK4/6 inhibitors are believed to increase the antigen presentation of cancer cells, increase the activity of tumor infiltration by CD45+ cells and effector T cell activation, as well as decreasing Treg cell proliferation. While these mechanisms have been well described in in vitro and animal models, they need to be studied in humans as soon as possible to understand them and allow investigators to take advantage of these novel aspects in clinical decision making. These findings may also pave the way for microbiome and immune-related data to be used as potential biomarkers for patient selection and response evaluations during therapy.

In addition to the clinical effects of being the standard care for breast cancer patients suffering from locally advanced breast cancer, neoadjuvant therapy is widely used to study the endocrinology of breast cancer in general and is recognized as one of the best model systems to predict responses in other clinical settings (early breast cancer or metastatic breast cancer). Tumor biopsies obtained before initiation of treatment and following six months of therapy will allow correlations to the individual type of clinical response (partial responses vs complete responses etc.). The research will focus on intratumoral mechanisms of adaption through tumor characterization using single cell technology which will allow investigators to follow both the different cancer clones as well as the evolution of different immune cells during therapy. Investigators will use novel approaches to evaluate liquid biopsies (measurement of cytokines levels, metabolites and cell free DNA-fragments etc.) during letrozole and ribociclib therapy using state of the art laboratory methods available at the host hospital and in the laboratories of the listed collaborators.

Thus, all in all, the planned study will be able to contribute to the basic understanding of this very potent new drug combination that may be used in large groups of breast cancer patients in the future, including locally advanced breast cancer, hopefully reducing the use of traditional chemotherapy in this setting.

Multicentre, single-arm, open-label, neoadjuvant study model

Neoadjuvant Treatment of Locally-advanced Breast Cancer Patients With Ribociclib and Letrozole

Presurgical Treatment With Ribociclib and Letrozole in Patients With Locally Advanced Breast Cancer: the NEOLETRIB Study.

Norwegian data protection laws are very strict, and free access to patient data is not possible. Authorised Norwegian researchers who wish to gain access to the data may apply individually to the study PI.

In order to accurately profile changes in the composition of the tumor over time and identify potentially-related biomarkers of response within the tumor, single cell RNA panels will be performed at three points during the treatment period. Samples of tumor tissue will be obtained, and the cells dissociated at the single cell level. These dissociated cells will then be subjected to RNA profiling via scRNA-seq. Genes expressed at a rate higher than the threshhold (generally 50 reads per kb per million reads) will be examined using t-Distributed Stochastic Neighbor Embedding, (tSNE) clustering, generally shown as a scatterplot, to allow the characterisation of phenotypes (clones). Using this technique, it will be evident which tumour phenotypes are eradicated by the treatment combination and which are not. This examination will also help to monitor patient response.

In order to examine the potential genetic changes within the tumor during treatment, samples of tumor tissue will be taken and examined using standard DNA profiling. Baseline samples will be compared to those at day 21 and at the time of surgery (6 months). This outcome will allow identification of overall tumour composition and changes to over the course of the therapy.

To determine the subtypes of the tumor, a PROSIGNA-test will be undertaken on all samples to confirm their subtype.

In order to examine the effects of letrozole and ribociclib on the presence of immune cells within the tumor throughout treatment, samples of tumor tissue will be extracted and cells will be dissociated at the single-cell level using enzymatic and mechanical means. Measurement of tumor neoantigens and testing of the ability of the T-cell receptors to recognise these neoantigens will assist in the understanding of the "rules" and molecular events underlying immune-mediated tumor destruction. Further, responders and non-responders will be compared to identify whether they belong to a new yet undiscovered subtype.

To ensure the correct patients are identified for participation in this study, and to record overall baseline information, samples of tumor tissue will be examined via standard histopathological investigations including subtyping, grading, ER-status, PGR-status, HER-2 status and level of Ki67-expression will be undertaken by a qualified pathologist. After the baseline, examination will confirm that biopsies consist of tumor tissue.

Using single-cell RNA-seq (scRNA-seq), thousands of individual cells will be profiled to build a cellular atlas of whole tumor biomarkers for targeted cancer treatments. scRNA-seq allows the characterisation of phenotypes (clones) to assist in determination of the phenotypes eradicated by the treatment, and to find biomarkers of response. Further knowledge of the phenotypes of the cells most affected by the therapy may assist in the identification of further drugs targeting any cells that remain or thrive.

Preoperative endocrine prognostic index (PEPI) status will be evaluated across the treatment period using the procedure outlined in Ellis et al, 2008.

Levels of Ki67 will be evaluated across the study period using the XXXXX protocol. Complete Cell Cycle Arrest (CCCA) will be recorded as a Ki67 of less than 2.7%.

A DNA-based approach to determination of fecal microbial composition will be performed. Stool samples will be collected at baseline, and during follow ups at day 21, day 90 and at time of surgery (day 180), and thereafter annually in years 1-5 (further if patient relapses). DNA purification from fecal samples will be performed using PSP Spin Stool DNA Plus Kit (Stratec Molecular GMBH). Next generation amplicon sequencing targeting the V4 region of the 16S rRNA gene (DNA) will be applied to detect the members of the fecal microbiota.

Serum cytokines will be measured using 54-plex cytokine panel, and analyzed with Luminex xMAP 200. The assay includes a series of known concentrations giving standard curves. Samples will be analyzed in duplicate.

Circulating metabolites will be identified using high resolution magic angle spinning mass spectrometry as described in Bathen et al (2013).

Circulating free tumor DNA will be collected and identified using standard DNA extraction and analysis techniques.

Study title	NCT ID	Conditions	Interventions	Eligibility	Organization	Link
Neoadjuvant Treatment of Locally-advanced Breast Cancer Patients With Ribociclib and Letrozole	NCT05163106	Breast Cancer HER2-negative B... ER-positive Bre... Locally Advance... Luminal A Breas... Luminal B Breas...	Letrozole 2.5mg... Goserelin	18 Years -	University Hospital, Akershus
Neoadjuvant Treatment of Locally-advanced Breast Cancer Patients With Ribociclib and Letrozole	NCT05163106	Breast Cancer HER2-negative B... ER-positive Bre... Locally Advance... Luminal A Breas... Luminal B Breas...	Letrozole 2.5mg... Goserelin	18 Years -	University Hospital, Akershus

Spots Global Cancer Trial Database for letrozole 2.5mg oral tablet; ribociclib 600mg oral tablet