Efficacy of olaparib in advanced cancers with germline or somatic mutations in BRCA1, BRCA2, CHEK2 and ATM, a Belgian Precision tumor-agnostic phase II study

SETD1A-dependent EME1 transcription drives PARPi sensitivity in HR deficient tumour cells

BACKGROUND

Cells deficient in DNA repair factors breast cancer susceptibility 1/2 (BRCA1/2) or ataxia-telangiectasia mutated (ATM) are sensitive to poly-ADP ribose polymerase (PARP) inhibitors. Building on our previous findings, we asked how the lysine methyltransferase SETD1A contributed to PARP inhibitor-mediated cell death in these contexts and determined the mechanisms responsible.

METHODS

We used cervical, breast, lung and ovarian cancer cells bearing mutations in BRCA1 or ATM and depleted SETD1A using siRNA or CRISPR/Cas9. We assessed the effects of the PARPi Olaparib on cell viability, homologous recombination, and DNA repair. We assessed underlying transcriptional perturbations using RNAseq. We used The Cancer Genomics Atlas (TCGA) and DepMap to investigate patient survival and cancer cell characteristics.

RESULTS

Loss of SETD1A from both BRCA1-deficient and ATM-deficient cancer cells was associated with resistance to Olaparib, explained by partial restoration of homologous recombination. Mechanistically, SETD1A-dependent transcription of the crossover junction endonuclease EME1 correlated with sensitivity to Olaparib in these cells. Accordingly, when SETD1A or EME1 was lost, BRCA1 or ATM-mutated cells became resistant to Olaparib, and homologous recombination was partially restored.

CONCLUSIONS

Loss of SETD1A or EME1 drives cellular resistance to Olaparib in certain genetic contexts and may help explain why patients develop resistance to PARP inhibitors in the clinic.

Limited association between HRR gene alterations and HRD in molecular tumor board cancer samples: Who should be tested for HRD?

Alterations in Homologous Recombination Repair (HRR) Pathway genes have been found to be associated with HR-Deficiency (HRD), which is an approved biomarker for PARP Inhibitor (PARPi) treatment. The aim of a Molecular Tumor Board (MTB) is to identify molecular alterations in cancer patients with advanced tumors that may suggest off-label treatment options. So far, few studies have analyzed the presence of HRR gene mutations and their association with HRD outside of clinical studies. Currently, no data on HRD testing in the setting of a MTB have been published. For the present study, a cohort of 237 patients encompassing 24 different tumor entities was collected from the MTB of the Comprehensive Cancer Center Erlangen-EMN. We show that an elevated Genomic Instability Score (GIS ≥42) can occur in samples with and without mutations in HRR-related genes. Overall, 38.1% of cancer samples with BRCA1/2 mutations, 10.9% of tumors with alterations in HRR genes other than BRCA1/2, and 4.3% of cancer samples without HRR gene mutations harbored an elevated GIS. Notably, our data show that various inactivating BRCA1/2 mutations are not associated with an elevated GIS. Taken together, panCancer assessment of HRD in addition to BRCA1/2 and other HRR gene mutational analysis is recommended to guide decisions regarding PARPi treatment. Further studies are needed to establish thresholds for GIS in non-ovarian cancer entities. Finally, HRD can be observed in 4.3% of BRCA1/2 and other HRR gene wildtype cancer samples, and may emerge as an independent biomarker for PARPi in the future.

Off-label use of olaparib in uncommon tumor locations in patients with impaired homologous recombination genes

OBJECTIVE

To describe the effectiveness and safety of olaparib off-label indications in patients with impaired homologous recombination genes and solid tumors different than those authorized.

METHODS

A single-center, observational and retrospective study including patients treated with olaparib for off-label use. The main variables were patient characteristics, prior therapies, response to therapy, progression-free survival, overall survival and adverse events.

RESULTS

A total of 6 patients were included. All patients had metastases and received 3 or more lines of prior treatment. The primary tumor locations and mutations were partner and localizer of BRCA2 (PALB2) intrahepatic cholangiocarcinoma, ataxia telangiectasia mutated (ATM) non-small cell lung adenocarcinoma, somatic breast cancer gene (sBRCA2) colorectal cancer, germinal breast cancer gene 2 (gBRCA2) breast neuroendocrine tumor, gBRCA2 ampullary cancer and gBRCA2 pancreatic neuroendocrine tumor. At the end of the study, one patient was still receiving olaparib showing more than 25 months of sustained stable disease response. No novel toxicities were observed besides those included in the product information.

CONCLUSIONS

There is limited published evidence on the use of olaparib in patients harboring pathogenic variants other than breast cancer genes, like PALB2 and ATM and conditions different than those authorized such as digestive tract, neuroendocrine and lung tumors. Further research is to assess the efficacy of olaparib in these patients.

The Landscape of PARP Inhibitors in Solid Cancers

PARP inhibitors are a class of agents that have shown significant preclinical activity in models defective in homologous recombination (HR). The identification of synthetic lethality between HR defects and PARP inhibition led to several clinical trials in tumors with known HR defects (initially mutations in BRCA1/2 genes and subsequently in other genes involved in HR). These studies demonstrated significant responses in breast and ovarian cancers, which are known to have a significant proportion of patients with HR defects. Since the approval of the first PARP inhibitor (PARPi), olaparib, several other inhibitors have been developed, expanding the armamentarium available to clinicians in this setting. The positive results obtained in breast and ovarian cancer have expanded the use of PARPi in other solid tumors with HR defects, including prostate and pancreatic cancer in which these defects have been identified. The clinical trials have demonstrated responses to PARPi which are now also available for the subset of patients with prostate and pancreatic cancer with HR defects. This review summarizes the results obtained in solid tumors with PARPi and their potential use when combined with other agents, including immune checkpoint inhibitors that are likely to further increase the survival of these patients which still needs a dramatic improvement.

Use of Olaparib in the Management of Metastatic Parathyroid Carcinoma With BRCA1 Mutation

Parathyroid carcinoma (PC) is a rare cause of primary hyperparathyroidism with a highly variable clinical course. We report the case of a man with metastatic PC who presented with severe hypercalcemia, discovered incidentally after a fall. He underwent left upper parathyroidectomy with left thyroid lobectomy, and pathology confirmed PC. After a year of absence from follow-up, he developed recurrence with bilateral pulmonary metastases. Cinacalcet and denosumab were initiated due to persistent, severe hypercalcemia, followed by wedge resection and palliative radiotherapy of pulmonary metastases. Genetic analysis revealed no actionable pathogenic variants, but a BRCA1 mutation classified as a variant of unknown significance (VUS) was identified. He was started on olaparib, a poly adenosine diphosphate-ribose polymerase (PARP) inhibitor, 3 years after initial diagnosis. Following this, his PTH level declined by approximately 40% within 7 months. Subsequently, his PTH levels began increasing despite continuation of olaparib and, after 20 months, rose to his original PTH level prior to the initiation of therapy. This is a unique case of a patient with metastatic PC who had a BRCA1 VUS mutation, with initial partial reduction in PTH and calcium levels after PARP inhibitor treatment.

Novel LZTR1 germline mutation as a mechanism of resistance to osimertinib in EGFR-mutated lung adenocarcinoma: a case report

Background

Tyrosine kinase inhibitors (TKIs) are now the standard of care first-line therapy for epidermal growth factor receptor (EGFR)-mutated advanced non-small cell lung cancer (NSCLC) patients. Despite positive outcomes in most patients, with extended progression-free survival (PFS), a small population of patients respond poorly to these drugs. Complex genetic and non-genetic resistance mechanisms may be the drivers of disease in cancer, but further research is required to identify these mechanisms in the clinic. Germline molecular testing alongside broad-panel somatic next-generation sequencing (NGS) has allowed for detection of resistance mutations in EGFR-mutated NSCLC patients that may be linked with poor response on TKIs.

Case Description

Here, we present a case of an NSCLC patient harboring an EGFR somatic mutation and a concomitant leucine-zipper-like transcriptional regulator-1 (LZTR1) germline mutation. The patient experienced rapid disease progression on first-line EGFR TKI, osimertinib-chemotherapy, combination therapy with a PFS of only 4 months as compared to the median PFS of 27.9 months in the FLAURA2 study.

Conclusions

This case report indicates that identification of germline resistance mutations such as LZTR1 may be associated with poor response to EGFR TKIs. Furthermore, further characterization of these resistance mutations beyond somatic mutations can aid in development of future therapeutic options, which currently do not exist. It is recommended that germline testing be performed as part of the initial patient workup, if available.

Targets for improving prostate tumor response to radiotherapy

Prostate cancer is a prevalent malignancy that is frequently managed with radiotherapy. However, resistance to radiotherapy remains a significant challenge in controlling this disease. Early radiotherapy is employed for locally confined prostate cancer (PCa), while recurrent disease post-surgery and metastatic castration-resistant prostate cancer (mCRPC) are treated with late-stage radiotherapy, including radium-223. Combination therapies to integrate radiotherapy and chemotherapy have demonstrated enhanced treatment efficacy. Nonetheless, both modalities can induce severe local and systemic toxicities. Consequently, selectively sensitizing prostate tumors to radiotherapy could improve therapeutic outcomes while minimizing systemic side effects. The mechanisms underlying radioresistance in prostate cancer are multifaceted, including DNA damage repair (DDR) pathways, hypoxia, angiogenesis, androgen receptor (AR) signaling, and immune evasion. The advent of 177Lu-PSMA-617, which was approved in 2022, has shown promise in targeting prostate-specific membrane antigen (PSMA) in advanced prostate cancer. Experimental and clinical studies have yielded promising results in suppressing prostate tumors by targeting these pathways. This paper reviews potential targets for sensitizing prostate tumors to radiotherapy. We discuss cellular and molecular mechanisms contributing to therapy resistance and examine findings from experimental and clinical trials on promising targets and drugs that can be used in combination with radiotherapy.

Targeting DNA damage response in pancreatic ductal adenocarcinoma: A review of preclinical and clinical evidence

Pancreatic ductal adenocarcinoma (PDAC) is associated with one of the most unfavorable prognoses across all malignancies. In this review, we investigate the role of inhibitors targeting crucial regulators of DNA damage response (DDR) pathways, either as single treatments or in combination with chemotherapeutic agents and targeted therapies in PDAC. The most prominent clinical benefit of PARP inhibitors' monotherapy is related to the principle of synthetic lethality in individuals harboring BRCA1/2 and other DDR gene mutations as predictive biomarkers. Moreover, induction of BRCAness with inhibitors of RTKs, including VEGFR and c-MET and their downstream signaling pathways, RAS/RAF/MEK/ERK and PI3K/AKT/mTOR in order to expand the application of PARP inhibitors in patients without DDR mutations, has also been addressed. Other DDR-targeting agents beyond PARP inhibitors, including inhibitors of ATM, ATR, CHEK1/2, and WEE1 have also demonstrated their potential in preclinical models of PDAC and may hold promise in future studies.

PARP Inhibitors in Pancreatic Cancer with Homologous Recombination Repair Gene Mutations: A Single-Institution Experience

BACKGROUND

Limited data are available regarding the anticancer activity of PARP inhibitors (PARPis) in pancreatic cancer with mutations in HRR genes other than BRCA and PALB2.

METHODS

We retrospectively reviewed the clinical characteristics and outcomes of 48 patients with advanced pancreatic cancer harboring pathogenic germline and/or somatic HRR mutations who were treated with PARPis.

RESULTS

Thirty patients had germline (g)HRR mutations only, twelve had somatic (s)HRR mutations only, and six had concomitant gHRR and sHRR mutations. The objective response rate (ORR) was 22%. The median progression-free survival (mPFS) and overall survival (mOS) were 6.9 and 11.5 months, respectively. Five patients received olaparib in the front-line setting due to borderline performance status. Their ORR was 20%, and their mPFS and mOS were both 11.3 months. The ORR was higher in patients with BRCA or PALB2 mutations (germline or somatic) than in those with non-BRCA/PALB2 mutations. Patients with somatic non-BRCA/PALB2 variants had a shorter mPFS. Patients with concomitant gHRR/sHRR mutations or gHRR mutations alone had a significantly longer mPFS than those with sHRR mutations only.

CONCLUSIONS

PARP inhibitors may be considered for patients with advanced pancreatic cancer harboring pathogenic alterations of BRCA who cannot tolerate standard chemotherapy. Maintenance PARPis can be considered in selected patients with non-BRCA/non-PALB2 HRR mutations.

Developing combination therapies with biologics in triple-negative breast cancer

INTRODUCTION

Novel compounds have entered the triple-negative breast cancer (TNBC) treatment algorithm, namely immune checkpoints inhibitors (ICIs), PARP inhibitors and antibody-drug conjugates (ADCs). The optimization of treatment efficacy can be enhanced with the use of combination treatments, and the incorporation of novel compounds. In this review, we discuss the combination treatments under development for the treatment of TNBC.

AREAS COVERED

The development of new drugs occurring in recent years has boosted the research for novel combinations to target TNBC heterogeneity and improve outcomes. ICIs, ADCs, tyrosine kinase inhibitors (TKIs), and PARP inhibitors have emerged as leading players in this new landscape, while other compounds like novel intracellular pathways inhibitors or cancer vaccines are drawing more and more interest. The future of TNBC is outlined in combination approaches, and based on new cancer targets, including many chemotherapy-free treatments.

EXPERT OPINION

A large number of TNBC therapies have either proved clinically ineffective or weighted by unacceptable safety profiles. Others, however, have provided promising results and are currently in late-stage clinical trials, while a few have actually changed clinical practice in recent years. As novel, more and more selective drugs come up, combination strategies focusing the concept of synergy are fully warranted for the future.

Navigating Change in Tumor Naming: Exploring the Complexities and Considerations of Shifting Toward Molecular Classifications

Navigating change in tumor naming. Balance organ-based and molecular classifications for optimal treatment.

Tumor-Agnostic Therapy-The Final Step Forward in the Cure for Human Neoplasms?

Cancer accounted for 10 million deaths in 2020, nearly one in every six deaths annually. Despite advancements, the contemporary clinical management of human neoplasms faces a number of challenges. Surgical removal of tumor tissues is often not possible technically, while radiation and chemotherapy pose the risk of damaging healthy cells, tissues, and organs, presenting complex clinical challenges. These require a paradigm shift in developing new therapeutic modalities moving towards a more personalized and targeted approach. The tumor-agnostic philosophy, one of these new modalities, focuses on characteristic molecular signatures of transformed cells independently of their traditional histopathological classification. These include commonly occurring DNA aberrations in cancer cells, shared metabolic features of their homeostasis or immune evasion measures of the tumor tissues. The first dedicated, FDA-approved tumor-agnostic agent's profound progression-free survival of 78% in mismatch repair-deficient colorectal cancer paved the way for the accelerated FDA approvals of novel tumor-agnostic therapeutic compounds. Here, we review the historical background, current status, and future perspectives of this new era of clinical oncology.

Turning Points in Cross-Disciplinary Perspective of Primary Hyperparathyroidism and Pancreas Involvements: Hypercalcemia-Induced Pancreatitis, MEN1 Gene-Related Tumors, and Insulin Resistance

We aimed to provide an in-depth analysis with respect to three turning points in pancreas involvement in primary hyperparathyroidism (PHP): hypercalcemia-induced pancreatitis (HCa-P), MEN1 (multiple endocrine neoplasia)-related neuroendocrine tumors (NETs), and insulin resistance (IR). This was a comprehensive review conducted via a PubMed search between January 2020 and January 2024. HCa-P (n = 9 studies, N = 1375) involved as a starting point parathyroid NETs (n = 7) or pancreatitis (n = 2, N = 167). Case report-focused analysis (N = 27) showed five cases of pregnancy PHP-HCa-P and three reports of parathyroid carcinoma (female/male ratio of 2/1, ages of 34 in women, men of 56). MEN1-NET studies (n = 7) included MEN1-related insulinomas (n = 2) or MEN1-associated PHP (n = 2) or analyses of genetic profile (n = 3), for a total of 877 MEN1 subjects. In MEN1 insulinomas (N = 77), the rate of associated PHP was 78%. Recurrence after parathyroidectomy (N = 585 with PHP) was higher after less-than-subtotal versus subtotal parathyroidectomy (68% versus 45%, p < 0.001); re-do surgery was 26% depending on surgery for pancreatic NETs (found in 82% of PHP patients). MEN1 pathogenic variants in exon 10 represented an independent risk factor for PHP recurrence. A single pediatric study in MEN1 (N = 80) revealed the following: a PHP rate of 80% and pancreatic NET rate of 35% and 35 underlying germline MEN1 pathogenic variants (and 3/35 of them were newly detected). The co-occurrence of genetic anomalies included the following: CDC73 gene variant, glucokinase regulatory protein gene pathogenic variant (c.151C>T, p.Arg51*), and CAH-X syndrome. IR/metabolic feature-focused analysis identified (n = 10, N = 1010) a heterogeneous spectrum: approximately one-third of adults might have had prediabetes, almost half displayed some level of IR as reflected by HOMA-IR > 2.6, and serum calcium was positively correlated with HOMA-IR. Vitamin D deficiency was associated with a higher rate of metabolic syndrome (n = 1). Normocalcemic and mildly symptomatic hyperparathyroidism (n = 6, N = 193) was associated with a higher fasting glucose and some improvement after parathyroidectomy. This multilayer pancreas/parathyroid analysis highlighted a complex panel of connections from pathogenic factors, including biochemical, molecular, genetic, and metabolic factors, to a clinical multidisciplinary panel.

Multidisciplinary Standards and Evolving Therapies for Patients With Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDA) is a challenging disease that presents at an advanced stage and results in many symptoms that negatively influence patients' quality of life and reduce their ability to receive effective treatment. Early implementation of expert multidisciplinary care with nutritional support, exercise, and palliative care for both early-stage and advanced disease promises to maintain or improve the patients' physical, social, and psychological well-being, decrease aggressive interventions at the end of life, and ultimately improve survival. Moreover, advances in treatment strategies in the neoadjuvant and metastatic setting combined with novel therapeutic agents targeting the key drivers of the disease are leading to improvements in the care of patients with pancreatic cancer. Here, we emphasize the multidisciplinary supportive and therapeutic care of patients with PDA, review current guidelines and new developments of neoadjuvant and perioperative treatments for localized disease, as well as the treatment standards and the evolving field of precision oncology and immunotherapies for advanced PDA.

Upper Gastrointestinal Cancers and the Role of Genetic Testing

Beyond the few established hereditary cancer syndromes with an upper gastrointestinal cancer component, there is increasing recognition of the contribution of novel pathogenic germline variants (gPVs) to upper gastrointestinal carcinogenesis. The detection of gPVs has potential implications for novel treatment approaches of the index cancer patient as well as long-term implications for surveillance and risk-reducing measures for cancer survivors and far-reaching implications for the patients' family. With widespread availability of multigene panel testing, new associations may be identified with germline-somatic integration being critical to determining true causality of novel gPVs. Comprehensive cancer care should incorporate both somatic and germline testing.

Agnostic Administration of Targeted Anticancer Drugs: Looking for a Balance between Hype and Caution

Many tumors have well-defined vulnerabilities, thus potentially allowing highly specific and effective treatment. There is a spectrum of actionable genetic alterations which are shared across various tumor types and, therefore, can be targeted by a given drug irrespective of tumor histology. Several agnostic drug-target matches have already been approved for clinical use, e.g., immune therapy for tumors with microsatellite instability (MSI) and/or high tumor mutation burden (TMB), NTRK1-3 and RET inhibitors for cancers carrying rearrangements in these kinases, and dabrafenib plus trametinib for BRAF V600E mutated malignancies. Multiple lines of evidence suggest that this histology-independent approach is also reasonable for tumors carrying ALK and ROS1 translocations, biallelic BRCA1/2 inactivation and/or homologous recombination deficiency (HRD), strong HER2 amplification/overexpression coupled with the absence of other MAPK pathway-activating mutations, etc. On the other hand, some well-known targets are not agnostic: for example, PD-L1 expression is predictive for the efficacy of PD-L1/PD1 inhibitors only in some but not all cancer types. Unfortunately, the individual probability of finding a druggable target in a given tumor is relatively low, even with the use of comprehensive next-generation sequencing (NGS) assays. Nevertheless, the rapidly growing utilization of NGS will significantly increase the number of patients with highly unusual or exceptionally rare tumor-target combinations. Clinical trials may provide only a framework for treatment attitudes, while the decisions for individual patients usually require case-by-case consideration of the probability of deriving benefit from agnostic versus standard therapy, drug availability, associated costs, and other circumstances. The existing format of data dissemination may not be optimal for agnostic cancer medicine, as conventional scientific journals are understandably biased towards the publication of positive findings and usually discourage the submission of case reports. Despite all the limitations and concerns, histology-independent drug-target matching is certainly feasible and, therefore, will be increasingly utilized in the future.