Plasma ctDNA Monitoring of a PTCH1-Mutant Metastatic Adult Medulloblastoma Showing a Durable Benefit With Vismodegib

Adult medulloblastoma (MB) is a rare disease affecting 0.6 persons per million adults over 19 years of age. The SHH-activated/TP53-wild type is the most common subtype, accounting for 60% of adult MBs, being characterized by mutations in PTCH1, SMO, or the TERT promoter. Several small studies demonstrate objective but short-lived responses to SMO inhibitors such as vismodegib or sonidegib. Like other oncogene-addicted solid tumors, detection of the corresponding drivers through liquid biopsy could aid in the molecular diagnosis and monitoring of the disease through less invasive procedures. However, most studies have only evaluated cerebrospinal fluid as the ctDNA reservoir, and very limited evidence exists on the role of liquid biopsy in plasma in patients with primary central nervous system tumors, including MB. We present the case of a 26-year-old patient with a recurrent MB, in which next-generation sequencing (FoundationOne CDx) revealed a mutation in PTCH1, allowing the patient to be treated with vismodegib in second line, resulting in a durable benefit lasting for 1 year. Using an in-house digital PCR probe, the PTCH1 mutation could be tracked in ctDNA during treatment with first-line chemotherapy and while on treatment with vismodegib, demonstrating a precise correlation with the radiological and clinical behavior of the disease.

Major and durable responses to photon and electron-beam palliative radiotherapies after immune-checkpoint inhibitors in head and neck cancer

BACKGROUND

The immuno-modulatory effects of ionizing radiation are well-known and preclinical studies suggest a synergistic effect of combining radiotherapy (RT) and IO. However, data regarding the clinical activity and safety of this approach are limited.

METHODS

We present the cases of two patients with SCCHN primary progressing to PDL1-based IO within a clinical trial (NCT03383094), that received subsequent but not concurrent palliative RT using two different modalities (electron beam and photon beam therapies).

RESULTS

Both patients achieved major and durable responses at 4 irradiated sites, with excellent tolerance and no grade ≥ 3 toxicities. Complete response occurred in 3 of the disease areas (all locoregional) and partial response in 1 metastatic lesion.

CONCLUSION

Palliative radiotherapy after progression to IO was safe and demonstrated profound and durable responses in the cases presented.

Durable complete remission with local therapies after neoadjuvant and adjuvant nivolumab in recurrent/metastatic head and neck cancer

Up to 10-15% of patients with first-line recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) present with platinum-refractory disease. The anti-PD1 nivolumab is the first therapeutic option in this setting achieving a 19.2% objective response rate and a 7.7-month median overall survival (OS). Given the poor prognosis of platinum-refractory patients, those showing slow progressive disease with no functional status deterioration should maintain nivolumab beyond progression in the absence of severe or unmanageable toxicities. Another strategy is to use local therapies such as radiotherapy and surgical tumor resection in cases of oligometastatic or oligoprogressive disease. Both strategies may significantly improve disease control and OS in these populations. We present the case of a patient with platinum-refractory disease treated with first-line nivolumab beyond progression who achieved a durable complete response after palliative radiation and surgical resection of five tumor lesions. To our knowledge, this is the first reported case of an R/M HNSCC treated with such a strategy outside a clinical trial and contributes to the evidence for combining anti-PD1 agents and local therapies in selected patients with R/M HNSCC.

Clinical Behavior, Mutational Profile and T-Cell Repertoire of High-Grade Neuroendocrine Tumors of the Head and Neck

Neuroendocrine carcinomas (NECs) of the head and neck (HN) account for <1% of HN cancers (HNCs), with a 5-year overall survival (OS) <20%. This is a retrospective study of HN NECs diagnosed at our institution between 2005 and 2022. Immunohistochemistry and next-generation sequencing (NGS) were used to evaluate neuroendocrine markers, tumor mutational burden (TMB), mutational profiles and T-cell receptor repertoires. Eleven patients with high-grade HN NECs were identified (male:female ratio 6:5; median age 61 (Min-Max: 31-86)): nasoethmoidal (3), parotid gland (3), submaxillary gland (1), larynx (3) and base of tongue (1). Among n = 8 stage II/IVA/B, all received (chemo)radiotherapy with/without prior surgery or induction chemotherapy, with complete response in 7/8 (87.5%). Among n = 6 recurrent/metastatic patients, three received anti-PD1 (nivolumab (2), pembrolizumab (1)): two achieved partial responses lasting 24 and 10 months. After a median follow-up of 30 and 23.5 months since diagnosis and since recurrent/metastatic, median OS was not reached. Median TMB (n = 7) was 6.72 Mut/Mb. The most common pathogenic variants were TP53, HNF1A, SMARCB1, CDKN2A, PIK3CA, RB1 and MYC. There were 224 median TCR clones (n = 5 pts). In one patient, TCR clones increased from 59 to 1446 after nivolumab. HN NECs may achieve long-lasting survival with multimodality treatment. They harbor moderate-high TMBs and large TCR repertoires, which may explain responses to anti-PD1 agents in two patients and justify the study of immunotherapy in this disease.

Paclitaxel Plus Cetuximab as Induction Chemotherapy for Patients With Locoregionally Advanced Head and Neck Squamous Cell Carcinoma Unfit for Cisplatin-Based Chemotherapy

Objectives

Induction chemotherapy (ICT) followed by definitive treatment is an accepted non-surgical approach for locoregionally advanced head and neck squamous cell carcinoma (LA-HNSCC). However, ICT remains a challenge for cisplatin-unfit patients. We evaluated paclitaxel and cetuximab (P-C) as ICT in a cohort of LA-HNSCC patients unfit for cisplatin.

Materials and Methods

This is a retrospective analysis of patients with newly diagnosed LA-HNSCC considered unfit for cisplatin-based chemotherapy (age >70 and/or ECOG≥2 and/or comorbidities) treated with weekly P-C followed by definitive radiotherapy and cetuximab (RT-C) between 2010 and 2017. Toxicity and objective response rate (ORR) to ICT and RT-C were collected. Median overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan–Meier method. Cox regression analysis was performed to determine baseline predictors of OS and PFS.

Results

A total of 57 patients were included. Grade 3–4 toxicity rate to ICT was 54.4%, and there was a death deemed treatment-related (G5). P-C achieved an ORR of 66.7%, including 12.3% of complete responses (CR). After P-C, 45 patients (78.9%) continued with concomitant RT-C. Twenty-six patients (45.6%) achieved a CR after definitive treatment. With a median follow-up of 21.7 months (range 1.2–94.6), median OS and PFS were 22.9 months and 10.7 months, respectively. The estimated 2-year OS and PFS rates were 48.9% and 33.7%, respectively. Disease stage had a negative impact on OS (stage IVb vs. III–IVa: HR = 2.55 [1.08–6.04], p = 0.03), with a trend towards worse PFS (HR = 1.92 [0.91–4.05], p = 0.09). Primary tumor in the larynx was associated with improved PFS but not OS (HR = 0.45 [0.22–0.92], p = 0.03, and HR = 0.69 [0.32–1.54], p = 0.37, respectively).

Conclusion

P-C was a well-tolerated and active ICT regimen in this cohort of LA-HNSCC patients unfit for cisplatin-based chemotherapy. P-C might represent a valid ICT option for unfit patients and may aid patient selection for definitive treatment.

Durable benefit and change in TCR clonality with nivolumab in a Lynch syndrome-associated glioma

Germline replication-repair deficient (gRRD) gliomas are exceptional events, and only a few of them have been treated with immune checkpoint inhibitors (ICIs). Contrary to sporadic gliomas, where ICIs have failed to show any objective benefit, the very few patients with gRRD gliomas treated with ICIs to date seem to benefit from programmed-death-1 (PD-1) inhibitors, such as nivolumab or pembrolizumab, either in terms of durable responses or in terms of survival. T-cell immunohistochemistry (IHC) and T-cell receptor (TCR) repertoire using high-throughput next-generation sequencing (NGS) with the Oncomine TCR-Beta-SR assay (Thermo Fisher Scientific) were analyzed in pre- and post-nivolumab tumor biopsies obtained from a patient with a Lynch syndrome-associated glioma due to a germline pathogenic hMLH1 mutation. The aim was to describe changes in the T-cell quantity and clonality after treatment with nivolumab to better understand the role of acquired immunity in gRRD gliomas. The patient showed a slow disease progression and overall survival of 10 months since the start of anti-PD-1 therapy with excellent tolerance. A very scant T-cell infiltrate was observed both at initial diagnosis and after four cycles of nivolumab. The drastic change observed in TCR clonality in the post-nivolumab biopsy may be explained by the highly spatial and temporal heterogeneity of glioblastomas. Despite the durable benefit from nivolumab, the scant T-cell infiltrate possibly explains the lack of objective response to anti-PD-1 therapy. The major change in TCR clonality observed after nivolumab possibly reflects the evolving molecular heterogeneity in a highly pre-treated disease. An in-deep review of the available literature regarding the role of ICIs in both sporadic and gRRD gliomas was conducted.

Detection of IDH1 Mutations in Plasma Using BEAMing Technology in Patients with Gliomas

Simple Summary

In contrast with other solid tumors, only a few, small studies have shown the feasibility of detecting different biomarkers in the peripheral blood (PB) of patients with gliomas. A prospective study was conducted, enrolling 10 patients with gliomas where 33 consecutive PB samples were analyzed. Among the six patients with isocitrate dehydrogenase 1 (IDH1)-mutant tumors that were surveyed, circulating tumor DNA (ctDNA) was detected in PB in three of them (50%), at timepoints at which the patients were either untreated or exhibited progressive disease. While no false positives were identified, the false-negative rate was high, reaching 86% (18/21). Finally, in one of the IDH1-mutant cases, the Beads, Emulsion, Amplification and Magnetics (BEAMing) digital PCR technology detected one of the two IDH1 mutations that had been detected in the patient’s tumor sample in plasma, 7 years prior to its detection in blood.

Abstract

Molecular testing using blood-based liquid biopsy approaches has not been widely investigated in patients with glioma. A prospective single-center study enrolled patients with gliomas ranging from grade II to IV. Peripheral blood (PB) was drawn at different timepoints for circulating tumour DNA (ctDNA) monitoring. Next-generation sequencing (NGS) was used for the study of isocitrate dehydrogenase 1 (IDH1) mutations in the primary tumor. Beads, Emulsion, Amplification and Magnetics (BEAMing) was used for the study of IDH1 mutations in plasma and correlated with the NGS results in the tumor. Between February 2017 and July 2018, ten patients were enrolled, six with IDH1-mutant and four with IDH1 wild-type gliomas. Among the six IDH-mutant gliomas, three had the same IDH1 mutation detected in plasma (50%), and the IDH1-positive ctDNA result was obtained in patients either at diagnosis (no treatment) or during progressive disease. While the false-negative rate reached 86% (18/21), 15 out of the 18 (83%) plasma-negative results were from PB collected from the six IDH-mutant patients at times at which there was no accompanying evidence of tumor progression, as assessed by MRI. There were no false-positive cases in plasma collected from patients with IDH1 wild-type tumors. BEAMing detected IDH1 mutations in the plasma of patients with gliomas, with a modest clinical sensitivity (true positivity rate) but with 100% clinical specificity, with complete agreement between the mutant loci detected in tumor and plasma. Larger prospective studies should be conducted to expand on these findings, and further explore the clearance of mutations in PB from IDH1-positive patients in response to therapy.

Neoadjuvant immunotherapy in head and neck cancer: Rationale, current evidence and future perspective

Immune-checkpoint inhibitors (ICIs) have shown to improve survival in the first- and second-line settings of recurrent/metastatic squamous cell carcinoma of the head and neck (SCCHN). In the past two years more than a dozen neoadjuvant IO studies have been reported in SCCHN, demonstrating the feasibility of one or a few doses of single agent or combination ICIs. This approach seems safe with no surgical delays due to toxicity in most of the studies with no new safety signals. Efficacy in terms of pathologic response appears promising both with single-agent ICIs and especially with chemo-IO combinations. The scientific rationale and current clinical evidence of neoadjuvant IO trials in SCCHN will be reviewed, including currently debated aspects such as the methodology for radiological and pathological evaluation as well as types and criteria for biomarker use in this setting. Finally, the future perspective of neoadjuvant IO in SCCHN will be approached.

Immunotherapy in microsatellite instability metastatic colorectal cancer: Current status and future perspectives

BACKGROUND

Colorectal cancer (CRC) is one of the most frequent and deadly malignancies worldwide. This specific pathology is composed of various molecular entities, with distinct immunological phenotypes. In addition to KRAS, NRAS, and BRAF mutation status, other druggable alterations such as those in HER2, MET, NTRK, ALK, and ROS1 have been identified in recent years offering new therapeutic options for some patients with CRC.

AIM

This review will focus on the molecular biology, immunological fingerprints, and current clinical evidence for the use of immunotherapy in patients with CRC.

RELEVANCE FOR PATIENTS

High microsatellite instability (MSI-H) and mutations in mismatch repair genes constitute a new molecular entity within CRC, which is characterized by a high mutational and neoantigen burden, frequent immune cell infiltration, and where immune checkpoint inhibitors have shown high response and survival rates compared to microsatellite stable (MSS) tumors. Indeed, the approval of pembrolizumab in MSI-H tumors was the first agnostic FDA approval in solid tumors. While monotherapy with anti-programmed cell death protein-1 agents achieves objective response rates (ORR) of around 30% and 1-year overall survival (OS) rates of 76%, anti-PD1, and anti-CTLA4 combinations achieve a 55% ORR and a 1-year OS rate of 85%. Several ongoing trials are evaluating the use of different immunotherapy combinations, both in the advanced and early settings and in MSI-h and MSS CRCs.

Safety and Efficacy of Cetuximab-Based Salvage Chemotherapy After Checkpoint Inhibitors in Head and Neck Cancer

BACKGROUND

There are still few data on the activity and safety of cetuximab-based salvage chemotherapy after immunotherapy (SCAI) in patients with squamous cell cancer of the head and neck (SCCHN).

MATERIALS AND METHODS

This was a retrospective study of patients with SCCHN who received cetuximab-based SCAI after programmed cell death protein 1 or programmed cell death ligand 1(PD[L]1) inhibitors. Overall response rate (ORR) and disease control rate (DCR) with SCAI and with last chemotherapy before immunotherapy (LCBI) by RECIST 1.1, percentage change from baseline in target lesions (PCTL), progression-free survival (PFS), overall survival (OS), treatment compliance, and toxicity were evaluated.

RESULTS

Between March 2016 and November 2019, 23 patients were identified. SCAI consisted of cetuximab-based combinations (3-weekly cisplatin-5FU-cetuximab [n = 2], weekly paclitaxel-cetuximab [n = 17], weekly cisplatin-cetuximab [n = 2], weekly carboplatin-paclitaxel-cetuximab [n = 2]). ORR was 56.5% (11 partial response, 2 complete response). DCR was 78.3%. Among 13 objective responders, median best PCTL was -53.5% (range, -30% to -100%). Median OS and PFS were 12 months and 6 months, respectively. In 10 patients receiving LCBI, ORR to LCBI was 40%, whereas ORR to SCAI achieved 60%. In LCBI-treated patients, median PFS with LCBI was 8 months and median PFS and OS with SCAI were 7 months and 12 months, respectively. Reduced dose intensity of the chemotherapy and cetuximab components occurred in 82.6% and 52.2% of the patients. Grade 1 or 2 adverse events (AEs) occurred in all patients. Grade 3 or 4 AEs developed in 65%, being grade 3 in all of them except in one patient (grade 4 neutropenia). There were no treatment-related deaths.

CONCLUSION

Cetuximab-based salvage chemotherapy after PD(L)1 inhibitors associated with high response rates and deep tumor reductions with a manageable safety profile. Subsequent lines of therapy may explain the long survival achieved in our series. These results invite to design studies to elucidate the best therapeutic sequence in patients with SCCHN in the immunotherapy era.

IMPLICATIONS FOR PRACTICE

Cetuximab-based salvage chemotherapy (SCAI) achieved high response rates in patients with recurrent/metastatic squamous cell cancer of the head and neck (SCCHN) after progression to PD-1/PD-L1 inhibitors. Objective response rate was higher than and progression-free survival was comparable to that of chemotherapy administered before immunotherapy (IO). In most patients, SCAI consisted of weekly, well-tolerated regimens. These observations have implications for current practice because of the limited evidence to date in SCCHN and the scant therapeutic options in this disease and invite to elucidate which may be the best treatment sequence for patients with head and neck cancer in the IO era.

Long-term survival of a patient with programmed death ligand 1-negative lung adenocarcinoma and oligoprogressive disease treated with nivolumab and stereotactic body radiation therapy

Immune-checkpoint inhibitors have shown to prolong survival in patients with metastatic non-small cell lung cancer. Programmed death ligand 1 (PD-L1) expression is associated with a higher probability of response, although some patients with PD-L1 negative tumors may also respond or show durable stabilizations. However, the optimal strategy after progression to immunotherapy (IO) is not yet defined. Patients with oligometastatic disease may benefit from local treatments such as radiotherapy (RT), achieving significant local control rates. In addition, RT is claimed to have numerous immunogenic effects that could synergize with IO. We present the case of a complete responder to nivolumab that after a monotopic adrenal relapse received stereotactic body radiation therapy, followed by maintenance nivolumab achieving a partial response that is still ongoing. Aspects such as mechanisms of acquired resistance to PD-L1 inhibitors, the optimal management after progression, and the potential interplay between IO and RT are briefly reviewed and discussed.

Comparison of circulating tumor cells and cell-free DNA in the molecular characterization of patients with head and neck cancer

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Background: The role of liquid biopsy in diagnosis and therapy monitoring in patients with head and neck cancer has been much less studied compared to other cancers. Our aim was to evaluate the perfomance in the isolation and recovery for molecular characterization of circulating tumour cells (CTC) of a new immunoafinity-based method and to compare it with the molecular diagnostic yield of plasma cell-free DNA. Methods: Patients with recurrent/metastatic (RM) head and neck cancer (HNC) were enrolled prospectively. Forty mililiters (ml) of plasma were collected at one or several time-points. First blood draw was always collected before starting a new therapeutic intervention or at the time of radiologic progression. For CTC detection and isolation, either anti-EpCAM or both anti-EpCAM + anti-EGFR antibodies were used. Digital PCR and castPCR were used to study KRAS and PI3KCA mutations in non-squamous HNC. A 15-gene customized NGS panel was used to characterized both CTC and cfDNA in patients with squamous HNC. Results: Between February 2016 and October 2018, 14 patients with R/M HNC were included (n = 1 local-only disease, n = 10 local and distant disease, n = 3 distant-only disease). Squamous histology (S): n = 9. Non-squamous (NS): n = 5 (1 naso-ethmoidal intestinal-type adenocarcinoma, 1 parotid gland exadenoma pleomorfic carcinoma, 2 parotid-gland salivary duct carcinomas (SDC), 1 parotid-gland high-grade neuroendocrine carcinoma). Twenty-five CTC determinations were performed. In 5 patients serial CTC determinations were performed. Median CTC was 4 (min-max: 0-49). Median CTC among 11 CTC determinations in S-HNC was 4 (min-max: 0-49). Median CTC was 3 CTC (min-max: 0-26) among the 14 determinations performed in NS-HNC. Digital PCR unveiled mutations in CTC and in cfDNA in 2 of 4 patients tested with NS histology (KRAS, PIK3CA), with one of them being concordant for the specific mutation. NGS unveiled mutations in CTC in 7/9 patients and in cfDNA in 6/9 patients, with only one loci-concordant case between CTC and plasma. Conclusions: IsoFlux detected CTC in the majority of patients with R/M HNC, regardless of the histologic type, and allowed for molecular characterization of CTC using different techniques for mutational analysis. Both NGS and digital PCR allowed for the detection in cell-free DNA of commonly mutated genes in HNC. Liquid biopsy should be more actively studied in this disease in order to better define its role in diagnosis and therapeutic monitoring.

Plasma PD-L1 levels according to histologic grade and IDH status in patients with gliomas

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Background: Plasma immune biomarkers such as soluble plasma PD-L1 (sPD-L1) may serve as surrogates of the immune condition of cancer patients and be potential markers of response to different immunotherapy modalities. Very few data exist regarding sPD-L1 in patients with primary brain tumors. Our aim was to study the levels of sPD-L1 in patients with gliomas according to histologic grade and IDH mutation status. Methods: Patients (pts) with grade II to IV gliomas were prospectively enrolled. Single-time-point plasma samples were obtained prior to adjuvant radiotherapy +/- chemotherapy. sPD-L1 determined using ELISA with a rabbit polyclonal anti-PDL1/CD274 antibody as capture reagent. Results: Between February 2017 and August 2019, 44 patients (pts) with gliomas and 12 healthy controls (HC) were enrolled. N=11 grade II, n=9 grade III, n=24 grade IV; n=26 IDHwt, n=18 IDHmut. Higher sPD-L1 levels in glioma pts compared to HC (60.8 vs 47.8 ng/ml, p=0.05). Higher sPD-L1 levels in grade II vs grades III-IV (73.3 vs 60 ng/ml, p=0.09). Higher sPD-L1 in IDHmut grades II-III vs IDHwt grades II-III + IDHmut/wt grade IV (73 vs 59 ng/ml, p=0.07). Non-significantly higher sPD-L1 in grades II-III vs grade IV (73 vs 59 ng/ml, p=0.46). No difference in sPD-L1 in IDHmut vs IDHwt (63.3 vs 59.1 ng/ml, p=0.496), nor in IDHwt vs HC (59.1 vs 47.8 ng/ml, p=0.109). Trend to significance in IDHmut vs HC (63.3 vs 47.8, p=0.062). Conclusions: sPD-L1 levels were significantly higher in glioma pts compared to HC. A trend was seen towards higher sPD-L1 levels in lower-grade (grades II, III) IDHmut gliomas. These findings may indicate a different systemic immune profile for currently defined glioma groups based on histologic grade and IDH status and merit confirmation in a larger sample.

Association of Genomic Domains in BRCA1 and BRCA2 with Prostate Cancer Risk and Aggressiveness

Pathogenic sequence variants (PSV) in BRCA1 or BRCA2 (BRCA1/2) are associated with increased risk and severity of prostate cancer. We evaluated whether PSVs in BRCA1/2 were associated with risk of overall prostate cancer or high grade (Gleason 8+) prostate cancer using an international sample of 65 BRCA1 and 171 BRCA2 male PSV carriers with prostate cancer, and 3,388 BRCA1 and 2,880 BRCA2 male PSV carriers without prostate cancer. PSVs in the 3' region of BRCA2 (c.7914+) were significantly associated with elevated risk of prostate cancer compared with reference bin c.1001-c.7913 [HR = 1.78; 95% confidence interval (CI), 1.25-2.52; P = 0.001], as well as elevated risk of Gleason 8+ prostate cancer (HR = 3.11; 95% CI, 1.63-5.95; P = 0.001). c.756-c.1000 was also associated with elevated prostate cancer risk (HR = 2.83; 95% CI, 1.71-4.68; P = 0.00004) and elevated risk of Gleason 8+ prostate cancer (HR = 4.95; 95% CI, 2.12-11.54; P = 0.0002). No genotype-phenotype associations were detected for PSVs in BRCA1. These results demonstrate that specific BRCA2 PSVs may be associated with elevated risk of developing aggressive prostate cancer. SIGNIFICANCE: Aggressive prostate cancer risk in BRCA2 mutation carriers may vary according to the specific BRCA2 mutation inherited by the at-risk individual.

RAS analysis of circulating tumor cells from advanced colorectal cancer using BEAMing technology

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Background: RAS mutations predict a lack of response to anti-EGFR therapies in metastatic colorectal cancer (mCRC). BEAMing technology is useful for detecting hot-spot mutations in ctDNA in mCRC. Analysis of these mutations in DNA from Circulating Tumor Cells (CTC) may increase the predictive value in mCRC patients (pts). Our aim was to explore the feasibility of studying RAS status using BEAMing in DNA from CTC. Methods: First, spiking experiments (SE) using wild-type (WT) and KRAS-mutated (MUT) cell lines were performed to establish the limit of detection (LOD) for RAS analysis with BEAMing. Second, SE were performed with CTC collected by CellCelector (removes non-CTC background achieving 100% purity of CTC). Finally, BEAMing was used for RAS analysis in ctDNA and in DNA from CTC isolated either with IsoFlux or with CellCelector in 9 mCRC pts with confirmed RAS mutation in primary tumor. Total DNA from CTC was preamplified using RepliG. Results: In SE, 10 and 5 KRAS MUT-cells using different backgrounds of WT-cells (10-0.2% MUT-cells) were detected using BEAMing. However, 3 and 1 MUT-cells (0.009-0%) were not detected. In SE of CTCs collected with CellCelector, BEAMing detected KRAS mutations with 50, 20, 10, 6, 4, 2 and 1 cell (MAF: 23.8%±3.8). A mutation (codon 13) was detected in CTC from one patient positive in tissue and ctDNA (CellCelector; 15 CTCs; MAF: 11.4%). Discordant results were found in 8 patients when CTCs were isolated using Isoflux (min: 0, max: 9 CTCs). CTC from another patient were possibly mutated but WT in ctDNA. Conclusions: This pilot study indicates that RAS mutations can be detected in CTCs using BEAMing. Reducing the non-CTC cellular background may be needed in cases with low CTC number. Molecular information provided by CTC and ctDNA may prove complementary and useful for taking therapeutic decisions in mCRC. These results merit confirmation in larger, prospective studies.

Mutational profile of dysplastic lesions evolving to laryngeal cancer

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Background: Few studies have addressed the carcinogenic process of laryngeal cancer from its premalignant phases. Our aim was to compare mutational status of laryngeal dysplasias (LD) evolving to laryngeal cancer (ELC) and not evolving to LC (NELC). Methods: Retrospective study of LD diagnosed between 2007 and 2011. A customized 15-gene NGS panel (DICER, IRF6, NOTCH1, NOTCH2, NOTCH3, NOTCH2NLA, PIK3CA, PTEN, RB1, RIPK4, SYNE1, SYNE2, TP53, TP63, CASP8) was used for mutational analysis with Truseq Custom Amplicon (Illumina) performed in FFPE LD samples and results compared between LD-ELC and LD-NELC. Results: Sixty-four patients (pts) with LD were identified. LD-ELC (N = 23) and LD-NELC (N = 41) were scored as mild (N = 40; NELC: 32 / ELC:8), moderate (N = 8; NELC: 4/ ELC: 4) and severe (N = 16; NELC:5 / ELC: 11). Prior or current moderate-to-heavy tobacco smoking ( > 10 pack-year): 53/64 (83%). Males: N = 50 (ELC: 21; NELC: 29); Female: N = 14 (ELC: 2; NELC: 12). Median time to cancer among 23 LD-ELC: 8 m (range: 0-46). Forty-seven gene variants were detected in ELC not found in NELC, of which 27 were pathogenic/likely pathogenic: Frameshift: 8 (1 in NOTCH2, 1 in PTEN, 2 in RB1, 2 in SYNE1 y 2 in SYNE2); Stop-gained: 3 (1 in NOTCH2NL, 2 in SYNE2); Splicing: 3 (1 in RB1, 1 in RIPK4 y 1 in TP53); Missense: 12 (1 in IRF6, 2 in NOTCH1, 1 in RB1, 2 in RIPK4, 6 in SYNE1). Conclusions: LD from pts ELC showed a different mutational profile than LD-NELC. These results show promise for identifying pts at higher risk for developing LC and should be validated in a larger, prospective study.

PD-1 blockade after PD-(L)1 inhibitors in head and neck cancer: Role of immunotherapy rechallenge

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Background: Immunotherapy (IO) has shown to improve survival in recurrent or metastatic (R/M) squamous cell cancer of the head and neck (SCCHN) with a better toxicity profile than chemotherapy (CT). An increased objective response rate (ORR) to CT has been shown after PD(L)1 blockade in SCCHN and other solid tumors. However, there are no data regarding the safety and efficacy of PD(L)1 rechallenge in SCCHN. Methods: Retrospective study of patients with R/M SCCHN treated with PD-1 inhibitors after an overt clinical and radiological progression to PD(L)1 blockade. Post-IO CT regimens, overall survival (OS), objective response rates (ORR) and percentage of tumor reduction (PTR) with post-IO CT and toxicity of IO rechallenge were recorded. Results: Eight patients treated between October 2016 and October 2018, were included. All patients received the first IO (1st-IO) treatment within clinical trials (anti-PDL1: 7; anti-PD1: 1), and received rescue cetuximab-based CT at progression (PD) (ERBITAX: 7; EXTREME: 1). ORR to post-IO 1st rescue CT (1RCT): 7 partial responses (PR), 1 stable disease (SD). PTR to 1RCT (median): 45% (range: 40-80). All second IO (2nd-IO) treatments consisted of PD1 inhibitors (nivolumab) and 6 received rescue CT (2RCT) at PD (ERBITAX: 1; wkCDDP-Cetuximab: 2; EXTREME: 3). Only 1of 6 evaluable patients responded to 2nd-IO with 5 PD as best response. Median duration of 2nd-IO: 3 months (range: 1-6). ORR to 2RCT (5 evaluable): 4 PR, 1 PD. PTR to 2RCT (median): 30% (range: 30-80). No G3/4 toxicities were detected during 2nd-IO. Conclusions: No new safety signals were encountered during PD-1 blockade in patients with SCCHN previously treated with PD-(L)1 inhibitors. First and second IO treatments associated with increased response rates to subsequent CT compared with historical data. Clinical trials should try to address the optimal treatment sequence in the IO era.

Durable intracranial and extracranial response to nivolumab with appearance of secondary resistance in a heavily pretreated patient with head and neck cancer

BACKGROUND

Recently, nivolumab was approved in the second-line setting of squamous cell cancer of the head and neck (SCCHN). The benefits of PD-(L)1 inhibitors in PD-L1(-) tumors are unclear, and no reports exist on the activity of these agents in brain metastases from SCCHN. Little is known regarding the mechanisms underlying acquired resistance to PD-(L)1 inhibition.

METHODS

A patient with PD-L1(-) metastatic SCCHN progressing to cetuximab-based chemotherapy received third-line nivolumab. T cell infiltration and mRNA expression of immune-related genes were compared in prenivolumab and postnivolumab biopsies from a progressing tumor lesion.

RESULTS

An exceptional local and systemic response was achieved, including complete devitalization of brain metastases that lasted for more than a year. Increased T cell infiltration and upregulation of genes related to T cell exhaustion and resistance to PD-1 inhibition were found.

CONCLUSION

Durable responses to PD-(L)1 inhibitors may be observed in biomarker-negative SCCHN. Mechanisms of resistance should be studied.

Nasoethmoidal Intestinal-Type Adenocarcinoma Treated with Cetuximab: Role of Liquid Biopsy and BEAMing in Predicting Response to Anti-Epidermal Growth Factor Receptor Therapy

Sinonasal intestinal-type adenocarcinomas (SNS-ITAC) are very rare tumors that resemble colorectal cancer in many of their pathological and molecular characteristics. Indeed, in most published series, 10%-14% of SNS-ITAC harbor mutations in KRAS. There is no standard systemic treatment in recurrent or metastatic SNS-ITAC, and there is no evidence of the use of any targeted agent in this entity. We present the case of a recurrent nasoethmoidal ITAC informed as RAS and BRAF wild-type by standard real-time polymerase chain reaction methods and treated with first-line cetuximab and irinotecan without response. Circulating tumor cells coupled to highly sensitive DNA analyses unveiled a mutation in KRAS exon 2 codon 12. Subsequent studies in the primary tumor using BEAMing detected a mutation in the same codon, confirming the KRAS mutated status of the tumor, and possibly explaining the absence of treatment response. This case exemplifies how liquid biopsy can aid in the correct and real-time molecular characterization of tumors even in a rare nonmetastatic cancer of the head and neck. KEY POINTS: Sinonasal intestinal type adenocarcinomas (SNS-ITAC) are rare tumors that commonly develop after a prolonged exposure to organic dusts (wood, leather, etc.), and that resemble colorectal cancer in some of their morphological and molecular characteristics.KRAS mutations have been described in 10%-14% in most series. However, its predictive value for guiding treatment decisions with targeted therapies (i.e., anti-epidermal growth factor receptor [EGFR] therapy) has not been defined.The first case of an SNS-ITAC treated with anti-EGFR therapy (cetuximab) is reported. Analysis of DNA from circulating tumor cells (CTCs) unveiled a mutation in KRAS not detected by standard methods in the primary tumor. However, RAS analysis using BEAMing detected a mutation in the primary tumor in the same codon of KRAS originally detected in CTCs, altogether possibly explaining the lack of treatment response.Liquid biopsy may allow for an accurate molecular diagnosis in rare, organ-confined tumors where few therapeutic options exist. Highly sensitive molecular diagnostics may aid in better characterizing rare entities harboring potentially druggable targets.

Pancreatic acinar cell carcinoma with bilateral ovarian metastases, panniculitis and polyarthritis treated with FOLFIRINOX chemotherapy regimen. A case report and review of the literature

Pancreatic acinar cell carcinoma (PACC) is a rare pancreatic tumor, with an estimated frequency of less than 1% of pancreatic malignancies. There are no prospective studies to guide diagnostic or therapeutic algorithms. We report the case of a 36 year-old woman, diagnosed of a pancreatic tumor with liver and peritoneal metastases that was initially managed as a neuroendocrine tumor with temozolomide and capecitabine. After two cycles a severely painful arthritis developed in her left ankle with panniculitis and extensive fat necrosis, and CT scan demonstrated progressive disease. Pathology of the primary was reassessed establishing the diagnosis of PACC. The patient started treatment with FOLFIRINOX regimen, achieving clinical benefit and disease stabilization. We also briefly reviewed the literature on this rare subtype of pancreatic tumor.