Sotorasib in KRAS p.G12C-Mutated Advanced Pancreatic Cancer

Advances in Systemic Therapy in Pancreatic Cancer

Substantial progress has been made toward understanding biology and developing new therapies for pancreatic ductal adenocarcinoma (PDAC). In this review, new insights from genomic profiling, as well as implications for treatment and prognosis, are discussed. New standards of care approaches with a focus on drug therapies are discussed for the treatment of resectable and advanced PDAC. The role of targeted and immune therapies remains limited; cohorts likely to benefit from these approaches are discussed. Promising, preliminary results regarding experimental therapies are reviewed.

Neoadjuvant management of locally advanced pancreatic ductal adenocarcinoma - Heading towards a promising change in treatment paradigm

Traditional chemotherapy-based adjuvant therapies for locally advanced pancreatic ductal adenocarcinoma (PDAC) have been associated with poor clinical outcomes driven partly by its complex anatomy and molecular heterogeneity. Treatment for PDAC is challenged by presence of a dense tumour microenvironment involving an interplay of multiple tumoural and stromal components which promote metastatic oncogenic behaviour. PDAC also involves aberrations in multiple signalling pathways with paucity of treatment options against the most common mutations including KRAS, TP53, CDKN2A andSMAD4. However, recent discovery of new mechanisms implicated in pancreatic carcinogenesis have led to identification of promising mechanistic therapeutic targets such as NET1 and ULK1. Early evidence also suggests the utility of targeting multiple DNA repair processes, modulators of DNA replication and major DNA damage response regulators. We explore the clinical rationale behind a neoadjuvant therapeutic strategy and emerging predictors of survival benefit associated with this approach. We also discuss challenges and opportunities originating from recent clinical trials evaluating neoadjuvant treatments composed of various combinations of radiotherapy, chemotherapy and immunotherapeutic regimens that have aimed to address some of these biological challenges. Selective treatment of patients harbouring specific genomic aberrations with targeted agents and immunotherapy can translate into optimum survival outcomes in PDAC. We also share perspectives on emerging prospective clinical evidence regarding stromal modifying agents, such as Tumour Growth Factor-Beta and Connective Tissue Growth Factor inhibitors along with novel vaccination-based approaches in improving PDAC outcomes.

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.

Advances in Surgery and (Neo) Adjuvant Therapy in the Management of Pancreatic Cancer

A multimodality approach, which usually includes chemotherapy, surgery, and/or radiotherapy, is optimal for patients with localized pancreatic cancer. The timing and sequence of these interventions depend on anatomic resectability and the biological suitability of the tumor and the patient. Tumors with vascular involvement (ie, borderline resectable/locally advanced) require surgical reassessments after therapy and participation of surgeons familiar with advanced techniques. When indicated, venous reconstruction should be offered as standard of care because it has acceptable morbidity. Morbidity and mortality of pancreas surgery may be mitigated when surgery is performed at high-volume centers.

HSP70-mediated mitochondrial dynamics and autophagy represent a novel vulnerability in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC), the most prevalent type of pancreatic cancer, is one of the deadliest forms of cancer with limited therapy options. Overexpression of the heat shock protein 70 (HSP70) is a hallmark of cancer that is strongly associated with aggressive disease and worse clinical outcomes. However, the underlying mechanisms by which HSP70 allows tumor cells to thrive under conditions of continuous stress have not been fully described. Here, we report that PDAC has the highest expression of HSP70 relative to normal tissue across all cancers analyzed. Furthermore, HSP70 expression is associated with tumor grade and is further enhanced in metastatic PDAC. We show that genetic or therapeutic ablation of HSP70 alters mitochondrial subcellular localization, impairs mitochondrial dynamics, and promotes mitochondrial swelling to induce apoptosis. Mechanistically, we find that targeting HSP70 suppresses the PTEN-induced kinase 1 (PINK1) mediated phosphorylation of dynamin-related protein 1 (DRP1). Treatment with the HSP70 inhibitor AP-4-139B was efficacious as a single agent in primary and metastatic mouse models of PDAC. In addition, we demonstrate that HSP70 inhibition promotes the AMP-activated protein kinase (AMPK) mediated phosphorylation of Beclin-1, a key regulator of autophagic flux. Accordingly, we find that the autophagy inhibitor hydroxychloroquine (HCQ) enhances the ability of AP-4-139B to mediate anti-tumor activity in vivo. Collectively, our results suggest that HSP70 is a multi-functional driver of tumorigenesis that orchestrates mitochondrial dynamics and autophagy. Moreover, these findings support the rationale for concurrent inhibition of HSP70 and autophagy as a novel therapeutic approach for HSP70-driven PDAC.

The trend toward more target therapy in pancreatic ductal adenocarcinoma

INTRODUCTION

Despite the considerable progress made in cancer treatment through the development of target therapies, pancreatic ductal adenocarcinoma (PDAC) continues to exhibit resistance to this category of drugs. As a result, chemotherapy combination regimens remain the primary treatment approach for this aggressive cancer.

AREAS COVERED

In this review, we provide an in-depth analysis of past and ongoing trials on both well-known and novel targets that are being explored in PDAC, including PARP, EGFR, HER2, KRAS, and its downstream and upstream pathways (such as RAF/MEK/ERK and PI3K/AKT/mTOR), JAK/STAT pathway, angiogenesis, metabolisms, epigenetic targets, claudin, and novel targets (such as P53 and plectin). We also provide a comprehensive overview of the significant trials for each target, allowing a thorough glimpse into the past and future of target therapy.

EXPERT OPINION

The path toward implementing a target therapy capable of improving the overall survival of PDAC is still long, and it is unlikely that a monotherapy target drug will fulfill a meaningful role in addressing the complexity of this cancer. Thus, we discuss the future direction of target therapies in PDAC, trying to identify the more promising target and combination treatments, with a special focus on the more eagerly awaited ongoing trials.

KRAS-mediated upregulation of CIP2A promotes suppression of PP2A-B56α to initiate pancreatic cancer development

Oncogenic mutations in KRAS are present in approximately 95% of patients diagnosed with pancreatic ductal adenocarcinoma (PDAC) and are considered the initiating event of pancreatic intraepithelial neoplasia (PanIN) precursor lesions. While it is well established that KRAS mutations drive the activation of oncogenic kinase cascades during pancreatic oncogenesis, the effects of oncogenic KRAS signaling on regulation of phosphatases during this process is not fully appreciated. Protein Phosphatase 2A (PP2A) has been implicated in suppressing KRAS-driven cellular transformation. However, low PP2A activity is observed in PDAC cells compared to non-transformed cells, suggesting that suppression of PP2A activity is an important step in the overall development of PDAC. In the current study, we demonstrate that KRAS G12D induces the expression of both an endogenous inhibitor of PP2A activity, Cancerous Inhibitor of PP2A (CIP2A), and the PP2A substrate, c-MYC. Consistent with these findings, KRAS G12D sequestered the specific PP2A subunit responsible for c-MYC degradation, B56α, away from the active PP2A holoenzyme in a CIP2A-dependent manner. During PDAC initiation in vivo , knockout of B56α promoted KRAS G12D tumorigenesis by accelerating acinar-to-ductal metaplasia (ADM) and the formation of PanIN lesions. The process of ADM was attenuated ex vivo in response to pharmacological re-activation of PP2A utilizing direct small molecule activators of PP2A (SMAPs). Together, our results suggest that suppression of PP2A-B56α through KRAS signaling can promote the MYC-driven initiation of pancreatic tumorigenesis.

ctDNA whole exome sequencing in pancreatic ductal adenocarcinoma unveils organ-dependent metastatic mechanisms and identifies actionable alterations in fast progressing patients

Understanding progression mechanisms and developing new targeted therapies is imperative in pancreatic ductal adenocarcinoma (PDAC). In this study, 80 metastatic PDAC patients were prospectively recruited and divided into discovery (n=37) and validation (n=43) cohorts. Tumor and plasma samples taken at diagnosis were pair analyzed using whole exome sequencing (WES) in patients belonging to the discovery cohort alone. The variant allele frequency (VAF) of KRAS mutations was measured by ddPCR in plasma at baseline and response assessment in all patients. Plasma WES identified at least one pathogenic variant across the cohort, uncovering oncogenic mechanisms, DNA repair, microsatellite instability, and alterations in the TGFb pathway. Interestingly, actionable mutations were mostly found in plasma rather than tissue. Patients with shorter survival showed enrichment in cellular organization regulatory pathways. Through WES we could identify a specific molecular profile of patients with liver metastasis, which exhibited exclusive mutations in genes related to the adaptive immune response pathway, highlighting the importance of the immune system in liver metastasis development. Moreover, KRAS mutations in plasma (both at diagnosis and persistent at follow-up) correlated with shorter progression free survival (PFS). Patients presenting a reduction of over 84.75 % in KRAS VAF at response assessment had similar PFS to KRAS-negative patients. Overall, plasma WES reveals molecular profiles indicative of rapid progression, potentially actionable targets, and associations between adaptive immune response pathway alterations and liver tropism.

ZBTB11 Depletion Targets Metabolic Vulnerabilities in K-Ras Inhibitor Resistant PDAC

Over 95% of pancreatic ductal adenocarcinomas (PDAC) harbor oncogenic mutations in K-Ras. Upon treatment with K-Ras inhibitors, PDAC cancer cells undergo metabolic reprogramming towards an oxidative phosphorylation-dependent, drug-resistant state. However, direct inhibition of complex I is poorly tolerated in patients due to on-target induction of peripheral neuropathy. In this work, we develop molecular glue degraders against ZBTB11, a C 2 H 2 zinc finger transcription factor that regulates the nuclear transcription of components of the mitoribosome and electron transport chain. Our ZBTB11 degraders leverage the differences in demand for biogenesis of mitochondrial components between human neurons and rapidly-dividing pancreatic cancer cells, to selectively target the K-Ras inhibitor resistant state in PDAC. Combination treatment of both K-Ras inhibitor-resistant cell lines and multidrug resistant patient-derived organoids resulted in superior anti-cancer activity compared to single agent treatment, while sparing hiPSC-derived neurons. Proteomic and stable isotope tracing studies revealed mitoribosome depletion and impairment of the TCA cycle as key events that mediate this response. Together, this work validates ZBTB11 as a vulnerability in K-Ras inhibitor-resistant PDAC and provides a suite of molecular glue degrader tool compounds to investigate its function.

Inhibition of DEF-p65 Interactions as a Potential Avenue to Suppress Tumor Growth in Pancreatic Cancer

The limited success of current targeted therapies for pancreatic cancer underscores an urgent demand for novel treatment modalities. The challenge in mitigating this malignancy can be attributed to the digestive organ expansion factor (DEF), a pivotal yet underexplored factor in pancreatic tumorigenesis. The study uses a blend of in vitro and in vivo approaches, complemented by the theoretical analyses, to propose DEF as a promising anti-tumor target. Analysis of clinical samples reveals that high expression of DEF is correlated with diminished survival in pancreatic cancer patients. Crucially, the depletion of DEF significantly impedes tumor growth. The study further discovers that DEF binds to p65, shielding it from degradation mediated by the ubiquitin-proteasome pathway in cancer cells. Based on these findings and computational approaches, the study formulates a DEF-mimicking peptide, peptide-031, designed to disrupt the DEF-p65 interaction. The effectiveness of peptide-031 in inhibiting tumor proliferation has been demonstrated both in vitro and in vivo. This study unveils the oncogenic role of DEF while highlighting its prognostic value and therapeutic potential in pancreatic cancer. In addition, peptide-031 is a promising therapeutic agent with potent anti-tumor effects.

Post-marketing safety concerns of sotorasib: A disproportionality analysis based on FDA adverse event reporting system

Background

Sotorasib has been approved for the treatment of adult patients with KRAS G12C-mutated locally advanced or metastatic non-small cell lung cancer (NSCLC). Due to the limitations of clinical trials, potential adverse events (AEs) and long-term safety issues cannot be detected. The presented study aimed to evaluate sotorasib-associated AEs using the FDA Adverse Event Reporting System (FAERS) database.

Methods

Post-marketing AE reports of sotorasib in the database were collected for analysis. Disproportionality analyses, including the reporting odds ratio (ROR), proportional reporting ratio (PRR), information component (IC) and empirical bayes geometric mean (EBGM) algorithms, were performed to mine the signals of sotorasib-associated AEs. The median duration, quartiles and the Weibull shape parameter (WSP) test were used to assess the onset time data.

Results

The database contained 1538 cases of sotorasib as primary suspect (PS), with 27 signals detected, scattering in 5 SOCs. The SOC of hepatobiliary disorders (182, ROR 4.48, PRR 4.07, IC 2.02, EBGM 4.07) met the four methodological thresholds. The median onset time of sotorasib-associated AEs was 42 days (interquartile range [IQR] 14-86.75 days). Different SOCs had different types of risk over time.

Conclusion

After obtaining marketing authorization, the study identified all potentially relevant adverse event (AE) signals expected to have a reporting frequency higher than anticipated and characterized them during sotorasib treatment.

Genomic profiling of small bowel adenocarcinoma: a pooled analysis from 3 databases

BACKGROUND

Small bowel adenocarcinoma is a rare disease. The genomic profiling tumours according to clinical characteristics and its impact on the prognosis remains unclear.

METHODS

A pooled analysis of clinical data, genomic profiling and MisMatch Repair (MMR) status from three databases was performed.

RESULTS

A total of 188 tumour samples were analysed. A predisposing disease was reported in 22.3%, mainly Lynch syndrome and Crohn's disease. The tumours were localized in 80.2% and metastatic in 18.8%. The most frequent mutations were KRAS (42.0%) among them 7/79 are G12C, TP53 (40.4%), APC (19.1%), PIK3CA (18.6%), SMAD4 (12.8%) and ERBB2 (9.6%). Mutation distribution differed according to predisposing disease for TP53, ERBB2, IDH1, FGFR3, FGFR1 and KDR. KRAS and SMAD4 mutations were more frequent in metastatic tumour, whereas ERBB2 mutations were absent in metastatic tumour. For localized tumour, APC mutation was independently associated with a poor overall survival (OS) (p = 0.0254). 31.8% of localized tumours and 11.3% of metastatic tumours were dMMR (29.8% of the entire cohort). A dMMR status was associated with a better OS (HR = 0.61 [0.39-0.96], p = 0.0316).

CONCLUSIONS

There is a different genomic profile according to the stage and predisposing disease. dMMR and APC mutation in localized tumour predict a better prognosis.

Evaluation of KRAS inhibitor-directed therapies for pancreatic cancer treatment

Despite significant advancements in the treatment of other cancers, pancreatic ductal adenocarcinoma (PDAC) remains one of the world's deadliest cancers. More than 90% of PDAC patients harbor a Kirsten rat sarcoma (KRAS) gene mutation. Although the clinical potential of anti-KRAS therapies has long been realized, all initial efforts to target KRAS were unsuccessful. However, with the recent development of a new generation of KRAS-targeting drugs, multiple KRAS-targeted treatment options for patients with PDAC have entered clinical trials. In this review, we provide an overview of current standard of care treatment, describe RAS signaling and the relevance of KRAS mutations, and discuss RAS isoform- and mutation-specific differences. We also evaluate the clinical efficacy and safety of mutation-selective and multi-selective inhibitors, in the context of PDAC. We then provide a comparison of clinically relevant KRAS inhibitors to second-line PDAC treatment options. Finally, we discuss putative resistance mechanisms that may limit the clinical effectiveness of KRAS-targeted therapies and provide a brief overview of promising therapeutic approaches in development that are focused on mitigating these resistance mechanisms.

Precision medicine for pancreatic cancer: Characterizing the clinico-genomic landscape and outcomes of KRAS G12C-mutated disease

BACKGROUND

Mutated KRAS is the most common oncogene alteration in pancreatic cancer (PDAC), and KRAS G12C mutations (KRAS G12Cmut) are observed in 1-2%. Several inhibitors of KRAS G12C have recently demonstrated promise in solid tumors, including PDAC. Little is known regarding clinical, genomics and outcome data of this population.

METHODS

Patients with PDAC and KRAS G12Cmut were identified at Memorial Sloan Kettering Cancer Center (MSK), and via the AACR Project GENIE database. Clinical, treatment, genomic and outcomes data were analysed. A cohort of patients at MSK with non-G12C KRAS PDAC was included for comparison.

RESULTS

Among 3,571 patients with PDAC, 39 with KRAS G12Cmut were identified (1.1%). Median age was 67 years, 56% were female. Median BMI was 29.2 kg/m2, 67% had a smoking history. Median OS 13 months (9.4, not reached (NR)) for stage IV, and 26 months (23, NR) for stage I-III. Complete genomic data (via AACR GENIE) was available for N = 74. Most common co-alterations included: TP53 (73%), CDKN2A (33%), SMAD4 (28%), and ARID1A (21%). Compared with a large cohort (N = 2931) of non-G12C KRAS-mutated PDAC, ARID1A co-mutations were more frequent in KRAS G12Cmut (P < .05). OS did not differ between KRAS G12Cmut and non-G12C KRAS PDAC. Germline pathogenic variants were identified in 17%. N = 2 received KRAS G12C-directed therapy.

CONCLUSION

PDAC and KRAS G12Cmut may be associated with a distinct clinical phenotype. Genomic features are similar to non-G12C KRAS-mutated PDAC, although enrichment of ARID1A co-mutations was observed. Targeting of KRAS G12C in PDAC provides a precedent for broader KRAS targeting in PDAC.

KRAS G12C inhibitor combination therapies: current evidence and challenge

Although KRAS G12C inhibitors have proven that KRAS is a "druggable" target of cancer, KRAS G12C inhibitor monotherapies have demonstrated limited clinical efficacy due to primary and acquired resistance mechanisms. Multiple combinations of KRAS G12C inhibitors with other targeted therapies, such as RTK, SHP2, and MEK inhibitors, have been investigated in clinical trials to overcome the resistance. They have demonstrated promising efficacy especially by combining KRAS G12C and EGFR inhibitors for KRAS G12C-mutated colorectal cancer. Many clinical trials of combinations of KRAS G12C inhibitors with other targeted therapies, such as SOS1, ERK, CDK4/6, and wild-type RAS, are ongoing. Furthermore, preclinical data have suggested additional promising KRAS G12C combinations with YAP/TAZ-TEAD inhibitors, FAK inhibitors, and farnesyltransferase inhibitors. The combinations of KRAS G12C inhibitors with immunotherapies and chemotherapies have also been investigated, and the preliminary results were reported. More recently, KRAS-targeted therapies not limited to KRAS G12C are being developed, potentially broadening the treatment landscape of KRAS-mutated cancers. Rationally combining KRAS inhibitors with other therapeutics is likely to play a significant role in future treatment for KRAS-mutated solid tumors.

Genome-wide CRISPR screens identify PKMYT1 as a therapeutic target in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with an overall 5-year survival rate of <12% due to the lack of effective treatments. Novel treatment strategies are urgently needed. Here, PKMYT1 is identified through genome-wide CRISPR screens as a non-mutant, genetic vulnerability of PDAC. Higher PKMYT1 expression levels indicate poor prognosis in PDAC patients. PKMYT1 ablation inhibits tumor growth and proliferation in vitro and in vivo by regulating cell cycle progression and inducing apoptosis. Moreover, pharmacological inhibition of PKMYT1 shows efficacy in multiple PDAC cell models and effectively induces tumor regression without overt toxicity in PDAC cell line-derived xenograft and in more clinically relevant patient-derived xenograft models. Mechanistically, in addition to its canonical function of phosphorylating CDK1, PKMYT1 functions as an oncogene to promote PDAC tumorigenesis by regulating PLK1 expression and phosphorylation. Finally, TP53 function and PRKDC activation are shown to modulate the sensitivity to PKMYT1 inhibition. These results define PKMYT1 dependency in PDAC and identify potential therapeutic strategies for clinical translation.

Tumour-selective activity of RAS-GTP inhibition in pancreatic cancer

Broad-spectrum RAS inhibition has the potential to benefit roughly a quarter of human patients with cancer whose tumours are driven by RAS mutations1,2. RMC-7977 is a highly selective inhibitor of the active GTP-bound forms of KRAS, HRAS and NRAS, with affinity for both mutant and wild-type variants3. More than 90% of cases of human pancreatic ductal adenocarcinoma (PDAC) are driven by activating mutations in KRAS4. Here we assessed the therapeutic potential of RMC-7977 in a comprehensive range of PDAC models. We observed broad and pronounced anti-tumour activity across models following direct RAS inhibition at exposures that were well-tolerated in vivo. Pharmacological analyses revealed divergent responses to RMC-7977 in tumour versus normal tissues. Treated tumours exhibited waves of apoptosis along with sustained proliferative arrest, whereas normal tissues underwent only transient decreases in proliferation, with no evidence of apoptosis. In the autochthonous KPC mouse model, RMC-7977 treatment resulted in a profound extension of survival followed by on-treatment relapse. Analysis of relapsed tumours identified Myc copy number gain as a prevalent candidate resistance mechanism, which could be overcome by combinatorial TEAD inhibition in vitro. Together, these data establish a strong preclinical rationale for the use of broad-spectrum RAS-GTP inhibition in the setting of PDAC and identify a promising candidate combination therapeutic regimen to overcome monotherapy resistance.

Phase I/II Study of Combined BCL-xL and MEK Inhibition with Navitoclax and Trametinib in KRAS or NRAS Mutant Advanced Solid Tumors

PURPOSE

MEK inhibitors (MEKi) lack monotherapy efficacy in most RAS-mutant cancers. BCL-xL is an anti-apoptotic protein identified by a synthetic lethal shRNA screen as a key suppressor of apoptotic response to MEKi.

PATIENTS AND METHODS

We conducted a dose escalation study (NCT02079740) of the BCL-xL inhibitor navitoclax and MEKi trametinib in patients with RAS-mutant tumors with expansion cohorts for: pancreatic, gynecologic (GYN), non-small cell lung cancer (NSCLC), and other cancers harboring KRAS/NRAS mutations. Paired pretreatment and day 15 tumor biopsies and serial cell-free (cf)DNA were analyzed.

RESULTS

A total of 91 patients initiated treatment, with 38 in dose escalation. Fifty-eight percent had ≥3 prior therapies. A total of 15 patients (17%) had colorectal cancer, 19 (11%) pancreatic, 15 (17%) NSCLC, and 32 (35%) GYN cancers. The recommended phase II dose (RP2D) was established as trametinib 2 mg daily days 1 to 14 and navitoclax 250 mg daily days 1 to 28 of each cycle. Most common adverse events included diarrhea, thrombocytopenia, increased AST/ALT, and acneiform rash. At RP2D, 8 of 49 (16%) evaluable patients achieved partial response (PR). Disease-specific differences in efficacy were noted. In patients with GYN at the RP2D, 7 of 21 (33%) achieved a PR and median duration of response 8.2 months. No PRs occurred in patients with colorectal cancer, NSCLC, or pancreatic cancer. MAPK pathway inhibition was observed in on-treatment tumor biopsies. Reductions in KRAS/NRAS mutation levels in cfDNA correlated with clinical benefit.

CONCLUSIONS

Navitoclax in combination with trametinib was tolerable. Durable clinical responses were observed in patients with RAS-mutant GYN cancers, warranting further evaluation in this population.

Genomic determinants of biological aggressiveness and poor prognosis of pancreatic cancers: KRAS and beyond

INTRODUCTION

A marked histomolecular heterogeneity characterizes pancreatic cancer. Thus, different tumor histologies with divergent genomic profiles exist within the same category.

AREAS COVERED

Using data from PubMed, SCOPUS, and Embase (last search date: 04/04/2024), this expert-based, narrative review presents and discusses the essential molecular determinants of biological aggressiveness and poor prognosis in pancreatic cancer. First, KRAS mutation still represents one of the most critical difficulties in treating pancreatic cancers. In this district, it is mutated in > 90% of malignant tumors. Notably, actionable alterations for molecular-based therapies are typically lacking in KRAS-mutated pancreatic cancer. Furthermore, transcriptome-based studies clarified that the squamous phenotype is characterized by poorer prognosis and response to standard chemotherapy. We also discuss molecular biomarkers related to dismal prognosis in specific subsets of pancreatic cancer, such as SMAD4 in signet-ring cell carcinoma and TP53 in invasive cancers derived from intraductal tubulopapillary neoplasms.

EXPERT OPINION

The identification of the subgroups of pancreatic cancer with particularly unfavorable prognoses is a critical step for addressing specific research efforts. In addition to implementing and strengthening current precision oncology strategies, the decisive step for improving the survival of patients affected by pancreatic cancer must pass through targeting the KRAS gene.

Agnostic drug development revisited

The advent of molecular profiling and the generalization of next generation sequencing in oncology has enabled the identification of patients who could benefit from targeted agents. Since the tumor-agnostic approval of pembrolizumab for patients with MSI-High tumors in 2017, different molecularly-guided therapeutics have been awarded approvals and progressively incorporated in the treatment landscape across multiple tumor types. As the number of tumor-agnostic targets considered druggable expands in the clinic, novel challenges will reshape the drug development field involving all the stakeholders in oncology. In this review, we provide an overview of current tumor-agnostic approvals and discuss promising candidate therapeutics for tumor-agnostic designation and challenges for their broad implementation.

Current and Future Therapeutic Targets for Directed Molecular Therapies in Cholangiocarcinoma

We conducted a comprehensive review of the current literature of published data, clinical trials (MEDLINE; ncbi.pubmed.com), congress contributions (asco.org; esmo.org), and active recruiting clinical trains (clinicaltrial.gov) on targeted therapies in cholangiocarcinoma. Palliative treatment regimens were analyzed as well as preoperative and perioperative treatment options. We summarized the current knowledge for each mutation and molecular pathway that is or has been under clinical evaluation and discussed the results on the background of current treatment guidelines. We established and recommended targeted treatment options that already exist for second-line settings, including IDH-, BRAF-, and NTRK-mutated tumors, as well as for FGFR2 fusion, HER2/neu-overexpression, and microsatellite instable tumors. Other options for targeted treatment include EGFR- or VEGF-dependent pathways, which are known to be overexpressed or dysregulated in this cancer type and are currently under clinical investigation. Targeted therapy in CCA is a hallmark of individualized medicine as these therapies aim to specifically block pathways that promote cancer cell growth and survival, leading to tumor shrinkage and improved patient outcomes based on the molecular profile of the tumor.

Abrogation of KLF5 sensitizes BRCA1-proficient pancreatic cancer to PARP inhibition

Poly ADP-ribose polymerase (PARP) inhibitor monotherapies are selectively effective in patients with pancreatic, breast, prostate, and ovarian cancers with BRCA1 mutations. Cancer patients with more frequent wild-type BRCA show poor responses to PARP inhibitors. Moreover, patients who are initially sensitive to these inhibitors eventually respond poorly to drugs. In the present study, we discover that abrogation of Kruppel-like factor 5 (KLF5) significantly inhibits homologous recombination, which is the main mechanism for DNA double-stranded repair. Furthermore, the downregulation of KLF5 expression promotes the DNA damage induced by olaparib and significantly reduces the IC 50 of the RARP inhibitor in pancreatic cancer cells. Overexpression of BRCA1 reverses the above effects caused by silencing of KLF5. Olaparib combined with a KLF5 inhibitor has an enhanced cytotoxic effect. Mechanistically, we identify BRCA1 as a KLF5 target gene. BRCA1 is positively correlated with KLF5 in PDAC tissue. Our results indicate that inhibition of KLF5 may induce BRCAness in a larger pancreatic cancer subset with proficient BRCA. The combination of KLF5 inhibitors and PARP inhibitors provides a novel treatment strategy to enhance the sensitivity of BRCA1-proficient pancreatic cancer to PARP inhibitors.

Clinical impact of panel gene sequencing on therapy of advanced cancers of the digestive system: a retrospective, single center study

BACKGROUND

Panel gene sequencing is an established diagnostic tool for precision oncology of solid tumors, but its utility for the treatment of cancers of the digestive system in clinical routine is less well documented.

METHODS

We retrospectively identified patients with advanced or metastatic gastrointestinal, pancreaticobiliary or hepatic cancers who received panel gene sequencing at a tertiary university hospital from 2015 to 2022. For these cases, we determined the spectrum of genetic alterations, clinicopathological parameters and treatment courses. Assessment of actionability of genetic alterations was based on the OncoKB database, cancer-specific ESMO treatment guidelines, and recommendations of the local molecular tumor board.

RESULTS

In total, 155 patients received panel gene sequencing using either the Oncomine Focus (62 cases), Comprehensive (91 cases) or Childhood Cancer Research Assay (2 cases). The mean age of patients was 61 years (range 24-90) and 37% were female. Most patients suffered from either colorectal cancer (53%) or cholangiocellular carcinoma (19%). 327 genetic alterations were discovered in 123 tumor samples, with an average number of 2.1 alterations per tumor. The most frequently altered genes were TP53, KRAS and PIK3CA. Actionable gene alterations were detected in 13.5-56.8% of tumors, according to ESMO guidelines or the OncoKB database, respectively. Thirteen patients were treated with targeted therapies based on identified molecular alterations, with a median progression-free survival of 8.8 months.

CONCLUSIONS

Actionable genetic alterations are frequently detected by panel gene sequencing in patients with advanced cancers of the digestive tract, providing clinical benefit in selected cases. However, for the majority of identified actionable alterations, sufficient clinical evidence for targeted treatments is still lacking.

Tofacitinib to prevent anti-drug antibody formation against LMB-100 immunotoxin in patients with advanced mesothelin-expressing cancers

Background

LMB-100 is a mesothelin (MSLN)-targeting recombinant immunotoxin (iTox) carrying a Pseudomonas exotoxin A payload that has shown promise against solid tumors, however, efficacy is limited by the development of neutralizing anti-drug antibodies (ADAs). Tofacitinib is an oral Janus Kinase (JAK) inhibitor that prevented ADA formation against iTox in preclinical studies.

Methods

A phase 1 trial testing LMB-100 and tofacitinib in patients with MSLN-expressing cancers (pancreatic adenocarcinoma, n=13; cholangiocarcinoma, n=1; appendiceal carcinoma, n=1; cystadenocarcinoma, n=1) was performed to assess safety and to determine if tofacitinib impacted ADA formation. Participants were treated for up to 3 cycles with LMB-100 as a 30-minute infusion on days 4, 6, and 8 at two dose levels (100 and 140 µg/kg) while oral tofacitinib was administered for the first 10 days of the cycle (10 mg BID). Peripheral blood was collected for analysis of ADA levels, serum cytokines and circulating immune subsets.

Results

The study was closed early due to occurrence of drug-induced pericarditis in 2 patients. Pericarditis with the combination was not reproducible in a transgenic murine model containing human MSLN. Two of 4 patients receiving all 3 cycles of treatment maintained effective LMB-100 levels, an unusual occurrence. Sustained increases in systemic IL-10 and TNF-α were seen, a phenomenon not observed in prior LMB-100 studies. A decrease in activated T cell subsets and an increase in circulating immunosuppressive myeloid populations occurred. No radiologic decreases in tumor volume were observed.

Discussion

Further testing of tofacitinib to prevent ADA formation is recommended in applicable non-malignant disease settings.

Clinical trial registration

https://www.clinicaltrials.gov/study/NCT04034238.

The Genomic, Transcriptomic, and Immunologic Landscape of HRAS Mutations in Solid Tumors

Tipifarnib is the only targeted therapy breakthrough for HRAS-mutant (HRASmt) recurrent or metastatic head and neck squamous cell carcinoma (HNSCC). The molecular profiles of HRASmt cancers are difficult to explore given the low frequency of HRASmt. This study aims to understand the molecular co-alterations, immune profiles, and clinical outcomes of 524 HRASmt solid tumors including urothelial carcinoma (UC), breast cancer (BC), non-small-cell lung cancer (NSCLC), melanoma, and HNSCC. HRASmt was most common in UC (3.0%), followed by HNSCC (2.82%), melanoma (1.05%), BC (0.45%), and NSCLC (0.44%). HRASmt was absent in Her2+ BC regardless of hormone receptor status. HRASmt was more frequently associated with squamous compared to non-squamous NSCLC (60% vs. 40% in HRASwt, p = 0.002). The tumor microenvironment (TME) of HRASmt demonstrated increased M1 macrophages in triple-negative BC (TNBC), HNSCC, squamous NSCLC, and UC; increased M2 macrophages in TNBC; and increased CD8+ T-cells in HNSCC (all p < 0.05). Finally, HRASmt was associated with shorter overall survival in HNSCC (HR: 1.564, CI: 1.16-2.11, p = 0.003) but not in the other cancer types examined. In conclusion, this study provides new insights into the unique molecular profiles of HRASmt tumors that may help to identify new targets and guide future clinical trial design.

Somatic Mutational Analysis in Endoscopic Ultrasound-Guided Biopsy of Pancreatic Adenocarcinoma: Assessing Yield and Impact

INTRODUCTION

We sought to determine the yield of somatic mutational analysis from endoscopic ultrasound (EUS)-guided biopsies of pancreatic adenocarcinoma compared with that of surgical resection and to assess the impact of these results on oncologic treatment.

METHODS

We determined the yield of EUS sampling and surgical resection. We evaluated the potential impact of mutational analysis by identifying actionable mutations and its direct impact by reviewing actual treatment decisions.

RESULTS

Yield of EUS sampling was 89.5%, comparable with the 95.8% yield of surgical resection. More than a quarter in the EUS cohort carried actionable mutations, and of these, more than 1 in 6 had treatment impacted by mutational analysis.

DISCUSSION

EUS sampling is nearly always adequate for somatic testing and may have substantial potential and real impact on treatment decisions.

Second-Line Treatment of Pancreatic Adenocarcinoma: Shedding Light on New Opportunities and Key Talking Points from Clinical Trials

Despite improvements in overall cancer mortality, deaths related to pancreatic cancer continue to rise. Following first-line treatment, second-line options are significantly limited. Classically, first-line treatment consisted of either gemcitabine or 5-fluorouracil based systemic chemotherapy. Upon progression of disease or recurrence, subsequent second-line treatment is still gemcitabine or 5-fluorouracil based chemotherapy, depending on what was used in the first line and the timing of progression or recurrence. A better understanding of the molecular underpinnings of pancreatic adenocarcinoma (PDAC) has led to new treatment strategies including specifically targeting the desmoplastic stroma, cytokine signaling and actionable mutations. Furthermore, efforts are also directed to enhance the immunogenicity profile of PDAC's well-established immunologically "cold" tumor microenvironment. More recently, the outstanding response rates of chimeric antigen receptor T (CAR-T) cells in hematologic malignancies, have led to clinical trials to evaluate the treatment modality in PDAC. In this review, we summarize recently presented clinical trials for metastatic pancreatic adenocarcinoma with novel treatment approaches in the second line and beyond.

The Clinical Implications of KRAS Mutations and Variant Allele Frequencies in Pancreatic Ductal Adenocarcinoma

The KRAS proto-oncogene is a major driver of pancreatic tumorigenesis and is nearly ubiquitously mutated in pancreatic ductal adenocarcinoma (PDAC). KRAS point mutations are detected in over 90% of PDAC cases, and these mutations have been shown to be associated with worse therapy response and overall survival. Pathogenic KRAS mutations are mostly limited to codons 12, 13 and 61, with G12D, G12V, G12R, Q61H, and G13D accounting for approximately 95% of the mutant cases. Emerging data have shown the importance of specific mutant subtypes, as well as KRAS variant allele frequency on clinical prognosis. Furthermore, novel technologies and therapies are being developed to target specific mutant subtypes, with encouraging early results. In this paper, we aim to review the recent studies regarding the relative impact of specific mutant KRAS subtypes on oncologic outcomes, the application of variant allele frequency in next generation sequencing analyses, and the ongoing research into therapies targeting specific mutant KRAS subtypes.

Targeting KRAS in cancer

RAS family variants-most of which involve KRAS-are the most commonly occurring hotspot mutations in human cancers and are associated with a poor prognosis. For almost four decades, KRAS has been considered undruggable, in part due to its structure, which lacks small-molecule binding sites. But recent developments in bioengineering, organic chemistry and related fields have provided the infrastructure to make direct KRAS targeting possible. The first successes occurred with allele-specific targeting of KRAS p.Gly12Cys (G12C) in non-small cell lung cancer, resulting in regulatory approval of two agents-sotorasib and adagrasib. Inhibitors targeting other variants beyond G12C have shown preliminary antitumor activity in highly refractory malignancies such as pancreatic cancer. Herein, we outline RAS pathobiology with a focus on KRAS, illustrate therapeutic approaches across a variety of malignancies, including emphasis on the 'on' and 'off' switch allele-specific and 'pan' RAS inhibitors, and review immunotherapeutic and other key combination RAS targeting strategies. We summarize mechanistic understanding of de novo and acquired resistance, review combination approaches, emerging technologies and drug development paradigms and outline a blueprint for the future of KRAS therapeutics with anticipated profound clinical impact.

From bench to bedside: current development and emerging trend of KRAS-targeted therapy

Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) is the most frequently mutated oncogene in human cancers with mutations predominantly occurring in codon 12. These mutations disrupt the normal function of KRAS by interfering with GTP hydrolysis and nucleotide exchange activity, making it prone to the GTP-bound active state, thus leading to sustained activation of downstream pathways. Despite decades of research, there has been no progress in the KRAS drug discovery until the groundbreaking discovery of covalently targeting the KRASG12C mutation in 2013, which led to revolutionary changes in KRAS-targeted therapy. So far, two small molecule inhibitors sotorasib and adagrasib targeting KRASG12C have received accelerated approval for the treatment of non-small cell lung cancer (NSCLC) harboring KRASG12C mutations. In recent years, rapid progress has been achieved in the KRAS-targeted therapy field, especially the exploration of KRASG12C covalent inhibitors in other KRASG12C-positive malignancies, novel KRAS inhibitors beyond KRASG12C mutation or pan-KRAS inhibitors, and approaches to indirectly targeting KRAS. In this review, we provide a comprehensive overview of the molecular and mutational characteristics of KRAS and summarize the development and current status of covalent inhibitors targeting the KRASG12C mutation. We also discuss emerging promising KRAS-targeted therapeutic strategies, with a focus on mutation-specific and direct pan-KRAS inhibitors and indirect KRAS inhibitors through targeting the RAS activation-associated proteins Src homology-2 domain-containing phosphatase 2 (SHP2) and son of sevenless homolog 1 (SOS1), and shed light on current challenges and opportunities for drug discovery in this field.

[The use of targeted therapies in gastrointestinal oncology]

In recent years, several drugs have been approved that specifically target molecular changes in tumour cells. For patients with gastrointestinal cancer, this has contributed to a significant improvement in prognosis. This article provides an overview of the currently available treatment options and the underlying biomarkers of their mechanisms of action.The evaluation of biomarkers and the use of targeted therapeutics have now become standard care in gastrointestinal oncology. Beyond the molecular-targeted therapy options already approved in the European Union, there is a multitude of additional drugs and biomarkers available, which can also be used outside of formal approval (so-called off-label use). Examples of this are also discussed in this overview (e.g., HER2-targeted therapy for cholangiocarcinoma, the use of KRASG12C inhibitors, or checkpoint inhibition in microsatellite unstable ductal pancreatic carcinoma).The question whether the use of one of these therapeutics represents a possible treatment option for patients with gastrointestinal cancers is typically discussed in a Molecular Tumour Board after undergoing guideline-appropriate therapies.

Temporal trends and regional variability in BRAF and KRAS genetic testing in Denmark (2010-2022): Implications for precision medicine

OBJECTIVE

This study aims to evaluate the developments in the testing of Kirsten Rat Sarcoma viral oncogene homolog (KRAS) and v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) mutations across different cancer types and regions in Denmark from 2010 to 2022.

STUDY DESIGN AND SETTING

Using comprehensive data from the Danish health registries, we linked molecular test results from the Danish Pathology Registry with cancer diagnoses from the Danish National Patient Registry between 2010 and 2022. We assessed the frequency and distribution of KRAS and BRAF mutations across all cancer types, years of testing, and the five Danish regions.

RESULTS

The study included records of KRAS testing for 30 671 patients and BRAF testing for 30 860 patients. Most KRAS testing was performed in colorectal (78%) and lung cancer (18%), and BRAF testing in malignant melanoma (13%), colorectal cancer (67%), and lung cancer (12%). Testing rates and documentation mutational subtypes increased over time. Reporting of wildtype results varied between lung and colorectal cancer, with underreporting in lung cancer. Regional variations in testing and reporting were observed.

CONCLUSION

Our study highlights substantial progress in KRAS and BRAF testing in Denmark from 2010 to 2022, evidenced by increased and more specific reporting of mutational test results, thereby improving the precision of cancer diagnosis and treatment. However, persistent regional variations and limited testing for cancer types beyond melanoma, colorectal, and lung cancer highlight the necessity for a nationwide assessment of the optimal testing approach.

Treatment resistance in pancreatic and biliary tract cancer: molecular and clinical pharmacology perspectives

INTRODUCTION

Treatment resistance poses a significant obstacle in oncology, especially in biliary tract cancer (BTC) and pancreatic cancer (PC). Current therapeutic options include chemotherapy, targeted therapy, and immunotherapy. Resistance to these treatments may arise due to diverse molecular mechanisms, such as genetic and epigenetic modifications, altered drug metabolism and efflux, and changes in the tumor microenvironment. Identifying and overcoming these mechanisms is a major focus of research: strategies being explored include combination therapies, modulation of the tumor microenvironment, and personalized approaches.

AREAS COVERED

We provide a current overview and discussion of the most relevant mechanisms of resistance to chemotherapy, target therapy, and immunotherapy in both BTC and PC. Furthermore, we compare the different strategies that are being implemented to overcome these obstacles.

EXPERT OPINION

So far there is no unified theory on drug resistance and progress is limited. To overcome this issue, individualized patient approaches, possibly through liquid biopsies or single-cell transcriptome studies, are suggested, along with the potential use of artificial intelligence, to guide effective treatment strategies. Furthermore, we provide insights into what we consider the most promising areas of research, and we speculate on the future of managing treatment resistance to improve patient outcomes.

Combinatorial Approaches for Chemotherapies and Targeted Therapies With Radiation: United Efforts to Innovate in Patient Care

Combinatorial therapies consisting of radiation therapy (RT) with systemic therapies, particularly chemotherapy and targeted therapies, have moved the needle to augment disease control across nearly all disease sites for locally advanced disease. Evaluating these important combinations to incorporate more potent therapies with RT will aid our understanding of toxicity and efficacy for patients. This article discusses multiple disease sites and includes a compilation of contributions from expert Red Journal editors from each disease site. Leveraging improved systemic control with novel agents, we must continue efforts to study novel treatment combinations with RT.

Pancreatic cancer biomarkers: A pathway to advance in personalized treatment selection

Pancreatic cancer is one of the tumors with the worst prognosis, and unlike other cancers, few advances have been made in recent years. The only curative option is surgery, but only 15-20% of patients are candidates, with a high risk of relapse. In advanced pancreatic cancer there are few first-line treatment options and no validated biomarkers for better treatment selection. The development of targeted therapies in pancreatic cancer is increasingly feasible due to tumor-agnostic treatments, such as PARP inhibitors in patients with BRCA1, BRCA2 or PALB2 alterations or immunotherapies in patients with high microsatellite instability/tumor mutational burden. In addition, other therapeutic molecules have been developed for patients with KRAS G12C mutation or fusions in NTRK or NRG1. Consequently, there has been a growing interest in biomarkers that may help guide targeted therapy in pancreatic cancer. Therefore, this review aims to offer an updated perspective on biomarkers with therapeutic potential in pancreatic cancer.

Modelling the micro- and macro- environment of pancreatic cancer: from patients to pre-clinical models and back

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with very low survival rates. Over the past 50 years, improvements in PDAC survival have significantly lagged behind the progress made in other cancers. PDAC's dismal prognosis is due to typical late-stage diagnosis combined with lack of effective treatments and complex mechanisms of disease. We propose that improvements in survival are partly hindered by the current focus on largely modelling and targeting PDAC as one disease, despite it being heterogeneous. Implementing new disease-representative pre-clinical mouse models that capture this complexity could enable the development of transformative therapies. Specifically, these models should recapitulate human PDAC late-stage biology, heterogeneous genetics, extensive non-malignant stroma, and associated risk factors and comorbidities. In this Perspective, we focus on how pre-clinical mouse models could be improved to exemplify key features of PDAC micro- and macro- environments, which would drive clinically relevant patient stratification, tailored treatments and improved survival.

The Extracellular Niche and Tumor Microenvironment Enhance KRAS Inhibitor Efficacy in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease that lacks effective treatment options, highlighting the need for developing new therapeutic interventions. Here, we assessed the response to pharmacologic inhibition of KRAS, the central oncogenic driver of PDAC. In a panel of PDAC cell lines, inhibition of KRASG12D with MRTX1133 yielded variable efficacy in suppressing cell growth and downstream gene expression programs in 2D cultures. On the basis of CRISPR-Cas9 loss-of-function screens, ITGB1 was identified as a target to enhance the therapeutic response to MRTX1133 by regulating mechanotransduction signaling and YAP/TAZ expression, which was confirmed by gene-specific knockdown and combinatorial drug synergy. Interestingly, MRTX1133 was considerably more efficacious in 3D cell cultures. Moreover, MRTX1133 elicited a pronounced cytostatic effect in vivo and controlled tumor growth in PDAC patient-derived xenografts. In syngeneic models, KRASG12D inhibition led to tumor regression that did not occur in immune-deficient hosts. Digital spatial profiling on tumor tissues indicated that MRTX1133-mediated KRAS inhibition enhanced IFNγ signaling and induced antigen presentation that modulated the tumor microenvironment. Further investigation of the immunologic response using single-cell sequencing and multispectral imaging revealed that tumor regression was associated with suppression of neutrophils and influx of effector CD8+ T cells. Together, these findings demonstrate that both tumor cell-intrinsic and -extrinsic events contribute to response to MRTX1133 and credential KRASG12D inhibition as a promising therapeutic strategy for a large percentage of patients with PDAC.

SIGNIFICANCE

Pharmacologic inhibition of KRAS elicits varied responses in pancreatic cancer 2D cell lines, 3D organoid cultures, and xenografts, underscoring the importance of mechanotransduction and the tumor microenvironment in regulating therapeutic responses.

Farnesyl-transferase inhibitors show synergistic anticancer effects in combination with novel KRAS-G12C inhibitors

BACKGROUND

Inhibition of mutant KRAS challenged cancer research for decades. Recently, allele-specific inhibitors were approved for the treatment of KRAS-G12C mutant lung cancer. However, de novo and acquired resistance limit their efficacy and several combinations are in clinical development. Our study shows the potential of combining G12C inhibitors with farnesyl-transferase inhibitors.

METHODS

Combinations of clinically approved farnesyl-transferase inhibitors and KRAS G12C inhibitors are tested on human lung, colorectal and pancreatic adenocarcinoma cells in vitro in 2D, 3D and subcutaneous xenograft models of lung adenocarcinoma. Treatment effects on migration, proliferation, apoptosis, farnesylation and RAS signaling were measured by histopathological analyses, videomicroscopy, cell cycle analyses, immunoblot, immunofluorescence and RAS pulldown.

RESULTS

Combination of tipifarnib with sotorasib shows synergistic inhibitory effects on lung adenocarcinoma cells in vitro in 2D and 3D. Mechanistically, we present antiproliferative effect of the combination and interference with compensatory HRAS activation and RHEB and lamin farnesylation. Enhanced efficacy of sotorasib in combination with tipifarnib is recapitulated in the subcutaneous xenograft model of lung adenocarcinoma. Finally, combination of additional KRAS G1C and farnesyl-transferase inhibitors also shows synergism in lung, colorectal and pancreatic adenocarcinoma cellular models.

DISCUSSION

Our findings warrant the clinical exploration of KRAS-G12C inhibitors in combination with farnesyl-transferase inhibitors.

Genetic Signature of Human Pancreatic Cancer and Personalized Targeting

Pancreatic cancer is a highly lethal disease with a 5-year survival rate of around 11-12%. Surgery, being the treatment of choice, is only possible in 20% of symptomatic patients. The main reason is that when it becomes symptomatic, IT IS the tumor is usually locally advanced and/or has metastasized to distant organs; thus, early diagnosis is infrequent. The lack of specific early symptoms is an important cause of late diagnosis. Unfortunately, diagnostic tumor markers become positive at a late stage, and there is a lack of early-stage markers. Surgical and non-surgical cases are treated with neoadjuvant and/or adjuvant chemotherapy, and the results are usually poor. However, personalized targeted therapy directed against tumor drivers may improve this situation. Until recently, many pancreatic tumor driver genes/proteins were considered untargetable. Chemical and physical characteristics of mutated KRAS are a formidable challenge to overcome. This situation is slowly changing. For the first time, there are candidate drugs that can target the main driver gene of pancreatic cancer: KRAS. Indeed, KRAS inhibition has been clinically achieved in lung cancer and, at the pre-clinical level, in pancreatic cancer as well. This will probably change the very poor outlook for this disease. This paper reviews the genetic characteristics of sporadic and hereditary predisposition to pancreatic cancer and the possibilities of a personalized treatment according to the genetic signature.

Targeting KRAS mutations in pancreatic cancer: opportunities for future strategies

Targeting the RAS pathway remains the holy grail of precision oncology. In the case of pancreatic ductal adenocarcinomas (PDAC), 90-92% harbor mutations in the oncogene KRAS, triggering canonical MAPK signaling. The smooth structure of the altered KRAS protein without a binding pocket and its affinity for GTP have, in the past, hampered drug development. The emergence of KRASG12C covalent inhibitors has provided renewed enthusiasm for targeting KRAS. The numerous pathways implicated in RAS activation do, however, lead to the development of early resistance. In addition, the dense stromal niche and immunosuppressive microenvironment dictated by oncogenic KRAS can influence treatment responses, highlighting the need for a combination-based approach. Given that mutations in KRAS occur early in PDAC tumorigenesis, an understanding of its pleiotropic effects is key to progress in this disease. Herein, we review current perspectives on targeting KRAS with a focus on PDAC.

Adeno-to-squamous transition drives resistance to KRAS inhibition in LKB1 mutant lung cancer

KRASG12C inhibitors (adagrasib and sotorasib) have shown clinical promise in targeting KRASG12C-mutated lung cancers; however, most patients eventually develop resistance. In lung patients with adenocarcinoma with KRASG12C and STK11/LKB1 co-mutations, we find an enrichment of the squamous cell carcinoma gene signature in pre-treatment biopsies correlates with a poor response to adagrasib. Studies of Lkb1-deficient KRASG12C and KrasG12D lung cancer mouse models and organoids treated with KRAS inhibitors reveal tumors invoke a lineage plasticity program, adeno-to-squamous transition (AST), that enables resistance to KRAS inhibition. Transcriptomic and epigenomic analyses reveal ΔNp63 drives AST and modulates response to KRAS inhibition. We identify an intermediate high-plastic cell state marked by expression of an AST plasticity signature and Krt6a. Notably, expression of the AST plasticity signature and KRT6A at baseline correlates with poor adagrasib responses. These data indicate the role of AST in KRAS inhibitor resistance and provide predictive biomarkers for KRAS-targeted therapies in lung cancer.

Exploiting the therapeutic implications of KRAS inhibition on tumor immunity

Over the past decade, RAS oncogenic proteins have transitioned from being deemed undruggable to having two clinically approved drugs, with several more in advanced stages of development. Despite the initial benefit of KRAS-G12C inhibitors for patients with tumors harboring this mutation, the rapid emergence of drug resistance underscores the urgent need to synergize these inhibitors with other therapeutic approaches to improve outcomes. RAS mutant tumor cells can create an immunosuppressive tumor microenvironment (TME), suggesting an increased susceptibility to immunotherapies following RAS inhibition. This provides a rationale for combining RAS inhibitory drugs with immune checkpoint blockade (ICB). However, achieving this synergy in the clinical setting has proven challenging. Here, we explore how understanding the impact of RAS mutant tumor cells on the TME can guide innovative approaches to combining RAS inhibition with immunotherapies, review progress in both pre-clinical and clinical stages, and discuss challenges and future directions.

New clinical trial design in precision medicine: discovery, development and direction

In the era of precision medicine, it has been increasingly recognized that individuals with a certain disease are complex and different from each other. Due to the underestimation of the significant heterogeneity across participants in traditional "one-size-fits-all" trials, patient-centered trials that could provide optimal therapy customization to individuals with specific biomarkers were developed including the basket, umbrella, and platform trial designs under the master protocol framework. In recent years, the successive FDA approval of indications based on biomarker-guided master protocol designs has demonstrated that these new clinical trials are ushering in tremendous opportunities. Despite the rapid increase in the number of basket, umbrella, and platform trials, the current clinical and research understanding of these new trial designs, as compared with traditional trial designs, remains limited. The majority of the research focuses on methodologies, and there is a lack of in-depth insight concerning the underlying biological logic of these new clinical trial designs. Therefore, we provide this comprehensive review of the discovery and development of basket, umbrella, and platform trials and their underlying logic from the perspective of precision medicine. Meanwhile, we discuss future directions on the potential development of these new clinical design in view of the "Precision Pro", "Dynamic Precision", and "Intelligent Precision". This review would assist trial-related researchers to enhance the innovation and feasibility of clinical trial designs by expounding the underlying logic, which be essential to accelerate the progression of precision medicine.

New Function Annotation of PROSER2 in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis due to the absence of diagnostic markers and molecular targets. Here, we took an unconventional approach to identify new molecular targets for pancreatic cancer. We chose uncharacterized protein evidence level 1 without function annotation from extensive proteomic research on pancreatic cancer and focused on proline and serine-rich 2 (PROSER2), which ranked high in the cell membrane and cytoplasm. In our study using cell lines and patient-derived orthotopic xenograft cells, PROSER2 exhibited a higher expression in cells derived from primary tumors than in those from metastatic tissues. PROSER2 was localized in the cell membrane and cytosol by immunocytochemistry. PROSER2 overexpression significantly reduced the metastatic ability of cancer cells, whereas its suppression had the opposite effect. Proteomic analysis revealed that PROSER2 interacts with STK25 and PDCD10, and their binding was confirmed by immunoprecipitation and immunocytochemistry. STK25 knockdown enhanced metastasis by decreasing p-AMPK levels, whereas PROSER2-overexpressing cells increased the level of p-AMPK, indicating that PROSER2 suppresses invasion via the AMPK pathway by interacting with STK25. This is the first demonstration of the novel role of PROSER2 in antagonizing tumor progression via the STK25-AMPK pathway in PDAC. LC-MS/MS data are available at MassIVE (MSV000092953) and ProteomeXchange (PXD045646).

Impact of KRAS mutations and co-mutations on clinical outcomes in pancreatic ductal adenocarcinoma

The relevance of KRAS mutation alleles to clinical outcome remains inconclusive in pancreatic adenocarcinoma (PDAC). We conducted a retrospective study of 803 patients with PDAC (42% with metastatic disease) at MD Anderson Cancer Center. Overall survival (OS) analysis demonstrated that KRAS mutation status and subtypes were prognostic (p < 0.001). Relative to patients with KRAS wildtype tumors (median OS 38 months), patients with KRASG12R had a similar OS (median 34 months), while patients with KRASQ61 and KRASG12D mutated tumors had shorter OS (median 20 months [HR: 1.9, 95% CI 1.2-3.0, p = 0.006] and 22 months [HR: 1.7, 95% CI 1.3-2.3, p < 0.001], respectively). There was enrichment of KRASG12D mutation in metastatic tumors (34% vs 24%, OR: 1.7, 95% CI 1.2-2.4, p = 0.001) and enrichment of KRASG12R in well and moderately differentiated tumors (14% vs 9%, OR: 1.7, 95% CI 1.05-2.99, p = 0.04). Similar findings were observed in the external validation cohort (PanCAN's Know Your Tumor® dataset, n = 408).

Advancements in Preclinical Models of Pancreatic Cancer

ABSTRACT

Pancreatic cancer remains one of the deadliest of all cancer types with a 5-year overall survival rate of just 12%. Preclinical models available for understanding the disease pathophysiology have evolved significantly in recent years. Traditionally, commercially available 2-dimensional cell lines were developed to investigate mechanisms underlying tumorigenesis, metastasis, and drug resistance. However, these cells grow as monolayer cultures that lack heterogeneity and do not effectively represent tumor biology. Developing patient-derived xenografts and genetically engineered mouse models led to increased cellular heterogeneity, molecular diversity, and tissues that histologically represent the original patient tumors. However, these models are relatively expensive and very timing consuming. More recently, the advancement of fast and inexpensive in vitro models that better mimic disease conditions in vivo are on the rise. Three-dimensional cultures like organoids and spheroids have gained popularity and are considered to recapitulate complex disease characteristics. In addition, computational genomics, transcriptomics, and metabolomic models are being developed to simulate pancreatic cancer progression and predict better treatment strategies. Herein, we review the challenges associated with pancreatic cancer research and available analytical models. We suggest that an integrated approach toward using these models may allow for developing new strategies for pancreatic cancer precision medicine.

Unveiling the role of KRAS in tumor immune microenvironment

Kirsten rats sarcoma viral oncogene (KRAS), the first discovered human oncogene, has long been recognized as "undruggable". KRAS mutations frequently occur in multiple human cancers including non-small cell lung cancer(NSCLC), colorectal cancer(CRC) and pancreatic ductal adenocarcinoma(PDAC), functioning as a "molecule switch" determining the activation of various oncogenic signaling pathways. Except for its intrinsic pro-tumorigenic role, KRAS alteration also exhibits an unique immune signature characterized by elevated PD-L1 level and high tumor mutational burden(TMB). KRAS mutation shape an immune suppressive microenvironment by impeding effective T cells infiltration and recruiting suppressive immune cells including myeloid-derived suppressor cells(MDSCs), regulatory T cells(Tregs), cancer associated fibroblasts(CAFs). In immune checkpoint inhibitor(ICI) era, NSCLC patients with mutated KRAS tend to be more responsive to ICI than patients with intact KRAS. The hallmark for KRAS mutation is the existence of multiple kinds of co-mutations. Different types of co-alterations have distinct tumor microenvironment(TME) signatures and responses to ICI. TP53 co-mutation possess a "hot" TME and achieve higher response to immunotherapy while other loss of function mutation correlated with a "colder" TME and a poor outcome to ICI-based therapy. The groundbreaking discovery of KRAS G12C inhibitors significantly improved outcomes for this KRAS subtype even though efficacy was limited to NSCLC patients. KRAS G12C inhibitors also restore the suppressive TME, creating an opportunity for combinations with ICI. However, an inevitable challenge to KRAS inhibitors is drug resistance. Promising combination strategies such as combination with SHP2 is an approach deserve further exploration because of their immune modulatory effect.

K-ras gene mutation analysis to diagnosis pancreatic adenocarcinoma from endoscopic ultrasound-guided tissue acquisition; a systematic review and meta-analysis

BACKGROUND

Endoscopic ultrasound-guided tissue acquisition (EUS-TA) has high sensitivity for the pathological diagnosis of pancreatic masses, but also a high false-negative rate. K-ras gene mutations occur in over 75 % of pancreatic ductal adenocarcinomas (PDAC), and this meta-analysis evaluated the utility of detecting K-ras gene mutations from EUS-TA specimens for the diagnosis of PDAC.

METHODS

Relevant studies in PubMed, the Cochrane Library, and Web of Science were systematically searched. Meta-analysis was performed on data from the selected studies using a bivariate model to provide pooled values of sensitivity, specificity, and their 95 % confidence intervals (CIs).

RESULTS

This meta-analysis included 1521 patients (from 10 eligible studies) who underwent EUS-TA with K-ras gene mutation analysis for diagnosis of pancreatic solid masses. The pooled estimates of sensitivity and specificity were 76.6 % (95 % CI, 70.9-81.5 %) and 97.0 % (95 % CI, 94.0-98.5 %), respectively, for pathological diagnosis, 75.9 % (95 % CI 69.5-81.4 %) and 95.3 % (95 % CI, 92.3-97.2 %) for K-ras gene mutation analysis, and 88.7 % (95 % CI 87.1-91.7 %) and 94.9 % (95 % CI, 91.5-97.0 %) for pathological diagnosis in combination with K-ras gene mutation analysis. The sensitivity for diagnosis of PDAC was significantly higher for pathological diagnosis in combination with K-ras gene mutation analysis than for pathological diagnosis or K-ras gene mutation analysis alone (both, p < 0.001). There was no difference in specificity between pathological diagnosis in combination with K-ras gene mutation analysis and both either (p = 0.234, 0.945, respectively).

CONCLUSIONS

K-ras gene mutation analysis in combination with to pathological diagnosis of EUS-TA increases the accuracy of differential diagnosis of PDAC.

Vaccine antibodies against a synthetic epidermal growth factor variant enhance the antitumor effects of inhibitors targeting the MAPK/ERK and PI3K/Akt pathways

BACKGROUND

The EGFR pathway is involved in intrinsic and acquired resistance to a wide variety of targeted therapies in cancer. Vaccination represents an alternative to the administration of anti-EGFR monoclonal antibodies, such as cetuximab or panitumumab. Here, we tested if anti-EGF antibodies generated by vaccination (anti-EGF VacAbs) could potentiate the activity of drugs targeting the ERK/MAPK and PI3K/Akt pathways.

METHODS

Non-small cell lung cancer (NSCLC), colorectal cancer (CRC) and melanoma cell lines harboring KRAS, NRAS, BRAF and PIK3CA mutations were used. Anti-EGF VacAbs were obtained by immunizing rabbits with a fusion protein containing a synthetic, highly mutated variant of human EGF. Cell viability was determined by MTT, total and phosphorylated proteins by Western blotting, cell cycle distribution and cell death by flow cytometry and emergence of resistance by microscopic examination in low density cultures.

RESULTS

Anti-EGF VacAbs potentiated the antiproliferative effects of MEK, KRAS G12C, BRAF, PI3K and Akt inhibitors in KRAS, NRAS, BRAF and PIK3CA mutant cells and delayed the appearance of resistant clones in vitro. The effects of anti-EGF VacAbs were comparable or superior to those of panitumumab and cetuximab. The combination of anti-EGF VacAbs with the targeted inhibitors effectively suppressed EGFR downstream pathways and sera from patients immunized with an anti-EGF vaccine also blocked activation of EGFR effectors.

CONCLUSIONS

Anti-EGF VacAbs enhance the antiproliferative effects of drugs targeting the ERK/MAPK and PIK3CA/Akt pathways. Our data provide a rationale for clinical trials testing anti-EGF vaccination combined with inhibitors selected according to the patient's genetic profile.