Efficacy of Immune Checkpoint Inhibition and Cytotoxic Chemotherapy in Mismatch Repair-Deficient and Microsatellite Instability-High Pancreatic Cancer: Mayo Clinic Experience

Trametinib in combination with hydroxychloroquine or palbociclib in advanced metastatic pancreatic cancer: data from a retrospective, multicentric cohort (AIO AIO-TF/PAK-0123)

BACKGROUND

Preclinical models of pancreatic cancer (PDAC) suggest a synergistic role for combined MEK and autophagy signaling inhibition, as well as MEK and CDK4/6 pathway targeting. Several case reports implicate clinical activity of the combination of either trametinib and hydroxychloroquine (HCQ) in patients with KRAS-mutant PDAC or trametinib with CDK4/6 inhibitors in patients with KRAS and CDKN2A/B alterations. However, prospective data from clinical trials is lacking. Here, we aim to provide clinical evidence regarding the use of these experimental regimens in the setting of dedicated precision oncology programs.

METHODS

In this retrospective case series, PDAC patients who received either trametinib/HCQ (THCQ) or trametinib/palbociclib (TP) were retrospectively identified across 11 participating cancer centers in Germany.

RESULTS

Overall, 34 patients were identified. 19 patients received THCQ, and 15 received TP, respectively. In patients treated with THCQ, the median duration of treatment was 46 days, median progression-free survival (PFS) was 52 days and median overall survival (OS) was 68 days. In the THCQ subgroup, all patients evaluable for response (13/19) had progressive disease (PD) within 100 days. In the TP subgroup, the median duration of treatment was 60 days, median PFS was 56 days and median OS was 195 days. In the TP subgroup, 9/15 patients were evaluable for response, of which 1/9 showed a partial response (PR) while 8/9 had PD. One patient achieved a clinical benefit despite progression under TP.

CONCLUSION

THCQ and TP are not effective in patients with advanced PDAC harboring KRAS mutations or alterations in MAPK/CDKN2A/B.

Lynch Syndrome and Somatic Mismatch Repair Variants in Pancreas Cancer

Importance

Microsatellite (MS) instability (MSI-H) occurs frequently in Lynch syndrome (LS)-associated tumors and is associated with response to immune checkpoint blockade (ICB) therapy. MSI-H is conferred by germline or somatic variants in mismatch repair genes. The contribution of somatic oncogenesis to MSI-H in pancreatic cancer (PC) is unknown.

Objective

To evaluate an LS-related PC cohort to define clinicogenomic features, describe somatic MSI-H cases (germline negative), characterize response to ICB, and guide preferred MS testing methods.

Design, Setting, and Participants

This single-institution, retrospective analysis was conducted from March 2012 to July 2023 at Memorial Sloan Kettering Cancer Center and included 55 patients with PC and either an LS germline pathogenic variant (gPV) or somatic mismatch repair (MMR) variant.

Main Outcomes and Measures

Composite MMR and MS status determined using orthogonal methods. An artificial intelligence classifier was used to account for low-cellularity specimens. Demographic and clinical data were abstracted from medical record. Zygosity status and somatic comutation landscape analyzed.

Results

Fifty-five patients (23 women [42%]) had PC and an MMR variant: 32 (58%) had LS (LS cohort) and 23 (42%) had a somatic MMR variant (no germline pathogenic variant, somatic MMR cohort). In the LS cohort, 10 (31%) had gMSH2, 9 (28%) gMSH6, 8 (25%) gPMS2, 4 (13%) gMLH1, 1 (3%) gEPCAM. The median age at diagnosis was 68 years (range, 45-88 years). For composite MS status, 17 (59%) were MSI-H, 12 (41%) MS stable, and 3 MS unknown. Five cases were reclassified as MSI-H by the artificial intelligence classifier. In the somatic MMR cohort, 11 (48%) had MSH6, 7 (30%) MLH1, 3 (13%) MSH2, and 2 (9%) PMS2. The median age at diagnosis was 72 years (range, 66-85 years). For composite MS status, 10 (43%) were MSI-H, 11 (48%) MS stable, and 2 (9%) MS indeterminate. Six cases were reclassified as MSI-H by the artificial intelligence classifier. For the LS and somatic MMR cohorts, 20 received ICB (n = 17 MSI-H). The median ICB duration was 27.7 months (95% CI, 11.5 to not reached); the disease control rate was 80%.

Conclusion

The results of this cross-sectional study suggest that MSI-H occurs due to LS or somatic oncogenesis in PC. Orthogonal MS testing is key in PC; the artificial intelligence classifier reclassified approximately 20% of cases, most of which were low cellularity. ICB for patients with LS or somatic MSI-H PC provided significant benefit.

Identifying Actionable Alterations in KRAS Wild-Type Pancreatic Cancer

The 5-year relative survival rate for pancreatic cancer is currently the lowest among all cancer types with a dismal 13%. A Kirsten rat sarcoma virus (KRAS) gene mutation is present in approximately 90% of patients with pancreatic cancer; however, KRAS-specific drugs are not yet widely used in clinical practice for pancreatic cancer, specifically the KRASG12D variant. Advances in genomic testing revealed an opportunity to detect genetic alterations in a subset of patients with no KRAS mutation termed KRAS wild-type. Patients with KRAS wild-type tumors have a propensity to express driver alterations, hence paving the way for utilizing a targeted therapy approach either via clinical trials or standard-of-care drugs. These alterations include fusions, amplifications, translocations, rearrangements and microsatellite instability-high tumors and can be as high as 11% in some studies. Here, we discuss some of the most notable alterations in KRAS wild-type and highlight promising clinical trials.

Molecular testing for personalized therapy is underutilized in patients with borderline resectable and locally advanced pancreatic cancer - real world data from the NORPACT-2 study

BACKGROUND

International guidelines currently recommend the use of molecular testing in patients with advanced pancreatic cancer. The rate of actionable molecular alterations is low. The utility of molecular testing in patients with borderline resectable (BRPC) or locally advanced (LAPC) pancreatic cancer in real world clinical practice is unclear.

METHODS

188 consecutive patients included in a prospective, population-based study (NORPACT-2) in patients with BRPC and LAPC (2018-2020) were reviewed. Molecular testing was performed at the discretion of the treating oncologist and was not recommended as a routine investigation by the national guidelines. All patients were considered fit to undergo primary chemotherapy and potential surgical resection. The frequency and the results of molecular testing (microsatellite instability (MSI) and/or KRAS status) were assessed.

RESULTS

Thirty patients (16%) underwent molecular testing. MSI tumour was detected in one (3.6%) of 28 tested patients. The patient received immunotherapy and subsequently underwent surgical resection. Histological assessment of the resected specimen revealed a complete response. KRAS wild type was detected in one (14.3%) of seven tested patient. Patients who initiated FOLFIRINOX as the primary chemotherapy regimen (p = 0.022), or were being treated at one of the eight hospital trusts (p = 0.001) were more likely to undergo molecular testing.

CONCLUSIONS

Molecular testing was rarely performed in patients with BRPC or LAPC. Routine molecular testing for all patients with BRPC and LAPC should be considered to increase identification of targetable mutations and improve outcomes.

Complete pathological response to pembrolizumab in pretreated pancreatic acinar cell carcinoma

BACKGROUND

Therapeutic approach used for pancreatic ductal adenocarcinoma is usually translated also for the rarer acinar counterpart, which shows a different mutational landscape nevertheless. While dMMR/MSI-H status is rare in the ductal histotype, it appears to be more prevalent in pancreatic acinar cell carcinoma (PACC).

CASE PRESENTATION

We report the case of a patient with locally advanced MSI-H PACC in whom the treatment with the anti-PD-1 pembrolizumab, administered as third line, made possible surgical resection, achieving even an exceptional pathological complete response.

CONCLUSIONS

Treatment of PACC should be tailored based on the peculiar molecular features that distinguish PACC from ductal adenocarcinoma. Evaluation of potentially therapeutically targetable alterations should be mandatory in case of PACC diagnosis.

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.

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.

An overview of up-and-coming immune checkpoint inhibitors for pancreatic cancer

INTRODUCTION

Immune checkpoint inhibitors (ICIs) targeting programmed cell death protein-1 (PD-1/PD-L1) pathway as well as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) have demonstrated substantial potential in several malignancies. Pancreatic adenocarcinoma (PC) still carries a high mortality despite tremendous advances in the anti-cancer arsenal.

AREAS COVERED

In this review, we discuss completed and ongoing studies on various ICIs in PC. ICIs have not yielded significant benefits as monotherapy. However, the combination with currently utilized therapies as well as with several other newer forms of therapy has delineated encouraging results. Larger trials are currently underway to definitively characterize the utility of ICIs in the treatment algorithm of PC. ICIs are approved for cancers with mismatch repair deficiency (dMMR) or microsatellite instability-high tumors (MSI-H) as a tumor-agnostic treatment strategy usually referred to as hot tumors.

EXPERT OPINION

Studies evaluating different drugs to transform the tumor microenvironment (TME) from 'cold' to 'hot' have not shown promise in PC. There still needs to be more prospective trials evaluating the efficacy of the combination of ICIs with different therapeutic modalities in PC that can augment the immunogenic potential of those 'cold' tumors. Exploratory biomarker analysis may help us identify those subsets of PC patients who may particularly benefit from ICIs.