Druggable growth dependencies and tumor evolution analysis in patient-derived organoids of neuroendocrine neoplasms from multiple body sites

Neuroendocrine neoplasms (NENs) comprise well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Treatment options for patients with NENs are limited, in part due to lack of accurate models. We establish patient-derived tumor organoids (PDTOs) from pulmonary NETs and derive PDTOs from an understudied subtype of NEC, large cell neuroendocrine carcinoma (LCNEC), arising from multiple body sites. PDTOs maintain the gene expression patterns, intra-tumoral heterogeneity, and evolutionary processes of parental tumors. Through hypothesis-driven drug sensitivity analyses, we identify ASCL1 as a potential biomarker for response of LCNEC to treatment with BCL-2 inhibitors. Additionally, we discover a dependency on EGF in pulmonary NET PDTOs. Consistent with these findings, we find that, in an independent cohort, approximately 50% of pulmonary NETs express EGFR. This study identifies an actionable vulnerability for a subset of pulmonary NETs, emphasizing the utility of these PDTO models.

Radiotherapy, atezolizumab, and bevacizumab in rectal cancers with the aim of organ preservation: The TARZAN study

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Background: Rectal cancer is traditionally treated with total mesorectal excision (TME), with/without neoadjuvant radiotherapy (RT) and chemotherapy. This approach often leads to temporary or permanent colostomies and other long-term morbidity such as urinary and sexual dysfunction in over 60% of patients. Organ preservation is increasingly being pursued in patients with a clinical complete response (cCR) following neoadjuvant treatment, thereby aiming to avoid TME-surgery. Based on preclinical data suggesting immunomodulatory effects of RT, and the synergy of combined PD-L1/VEGF blockade in several tumor types, the TARZAN study (NCT04017455) combines these treatments aiming to increase chances of organ preservation in patients with mainly MMR proficient (pMMR) rectal cancer without the need for chemotherapy. Methods: Patients with clinical stage ≤T3ab N0-1 distal-mid rectal tumors without mesorectal fascia involvement underwent 5x5 Gy RT followed by 3 cycles of atezolizumab and bevacizumab. Response was evaluated by MRI and endoscopy. The primary endpoint was clinical complete and near-complete response (CR) rate at 12 weeks after RT. Secondary endpoints included safety, organ preservation, pathologic (near) CR in case of surgery, and relapse free survival. According to a Simon’s 2-stage design, ≥3 responders were needed in stage I (18 patients) to continue accrual into stage II. Here we report data from stage I. Results: Eighteen patients (14 male, median age 63), all with pMMR tumors, were treated. Six tumors were cN1 on MRI, 10/18 tumors were ≥4cm and for 10/18 patients abdominoperineal resection (APR) appeared necessary due to distal tumor location. At the time of response evaluation, (near-)CR was achieved in 10/18 (56%) patients according to the primary endpoint. With a median follow-up of 20 months, 9/18 (50%) patients remain without TME surgery. Of these 9 patients, 5 underwent local excision to achieve organ preservation and in 5 patients no additional intervention was needed (cCR). The remaining 9 patients underwent TME surgery (4 APR), and pathologic assessment revealed near-CR in two patients, and a pCR in one patient. Three patients developed distant recurrences, one in the organ-sparing group. Neoadjuvant treatment was well-tolerated with grade 3 study drug-related adverse events (AEs) in 1 (5%) patient. Grade 3 surgery-related AEs occurred in 5/9 (55%) patients, including 4 anastomotic leaks and 1 abscess. Conclusions: Neoadjuvant RT followed by atezolizumab and bevacizumab resulted in a promising rate of clinical (near-)CRs in 56% of patients without the need for chemotherapy, reaching the primary endpoint. Accrual is ongoing in stage II, in which an additional 20 patients will be treated. Clinical trial information: NCT04017455 .

Genomic analysis of early-stage lung cancer reveals a role for TP53 mutations in distant metastasis

Patients with non-small cell lung cancer (NSCLC) who have distant metastases have a poor prognosis. To determine which genomic factors of the primary tumor are associated with metastasis, we analyzed data from 759 patients originally diagnosed with stage I-III NSCLC as part of the AACR Project GENIE Biopharma Collaborative consortium. We found that TP53 mutations were significantly associated with the development of new distant metastases. TP53 mutations were also more prevalent in patients with a history of smoking, suggesting that these patients may be at increased risk for distant metastasis. Our results suggest that additional investigation of the optimal management of patients with early-stage NSCLC harboring TP53 mutations at diagnosis is warranted in light of their higher likelihood of developing new distant metastases.

Neoadjuvant atezolizumab plus docetaxel/oxaliplatin/capecitabine in non-metastatic gastric and gastroesophageal junction adenocarcinoma: The PANDA trial

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Background: Immune checkpoint blockade improves clinical outcomes for patients with gastric and gastro-esophageal junction (GEJ) cancers, but its efficacy and impact on the tumor microenvironment in non-metastatic, resectable disease remains largely unknown. Peri-operative FLOT, the current standard-of-care, leads to pathologic complete responses (pCR) and major pathologic responses (MPR) in 16% and 37% of patients, respectively. An important open question is whether PDL-1 blockade monotherapy can prime the tumor microenvironment in a favorable manner, prior to combination with chemotherapy. Methods: We report results from the phase 2 PANDA trial (NCT03448835) of neoadjuvant atezolizumab (anti-PDL-1) plus docetaxel, oxaliplatin, and capecitabine (DOC) in patients with resectable gastric or GEJ adenocarcinoma. Patients received a single cycle of atezolizumab monotherapy, followed by 4 cycles of atezolizumab+DOC. Tumor tissue was collected at baseline, after atezolizumab monotherapy, the first atezolizumab+DOC, and at resection. The primary endpoints were safety and feasibility in 20 patients, and secondary endpoints included MPR (<10% viable tumor rest) and disease-free survival. Results: Twenty patients, of which 18 with mismatch repair (MMR) proficient and two with MMR-deficient tumors, were evaluable for safety and efficacy analyses. MPR was observed in 14/20 patients (70%; 95% CI 46–88%), including 9 pCR (45%; 95% CI 23-68%). Among patients with intestinal type adenocarcinoma, 12/15 (80%; 95% CI 52-96%) had an MPR, with 9/15 (60%; 95% CI 32-84%) pCR. Treatment was well tolerated, with two patients (10%) experiencing a grade 3 immune adverse event. At a median follow-up of 29 months (IQR 16-34), 15 patients (75%) were alive and disease-free. None of the patients with an MPR recurred. All patients underwent resections without treatment-related delays and no unexpected surgical complications were documented. Translational analyses, including baseline PDL-1 CPS score and whole exome sequencing (WES), plus CD8 T-cell infiltration and RNA sequencing at 4 timepoints will be presented at the meeting. Conclusions: Our data show that the addition of atezolizumab to neoadjuvant chemotherapy leads to promising pathologic responses in gastric/GEJ adenocarcinoma, which appears to be higher than in historical controls, with no recurrences in responders. These data should be validated in a large randomized controlled trial. Clinical trial information: NCT03448835.

Neoadjuvant nivolumab, ipilimumab, and celecoxib in MMR-proficient and MMR-deficient colon cancers: Final clinical analysis of the NICHE study

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Background: The combination of PD-1 and CTLA4 blockade has changed the treatment landscape for several cancer types. Although this treatment is highly effective in metastatic mismatch-repair deficient (dMMR) colorectal cancers, metastatic MMR-proficient (pMMR) tumors do not respond. The NICHE study was the first neoadjuvant immunotherapy study in colon cancer (CC) to show impressive responses in 100% of dMMR ( n= 20) and 27% of pMMR ( n= 15) CC. In contrast, pathologic response to neoadjuvant chemotherapy using standard of care folfox is approximately 5% in dMMR tumors. Here we present the final efficacy data for the original NICHE study cohorts. Methods: Patients with non-metastatic, resectable dMMR or pMMR CC were treated with a single dose of ipilimumab 1mg/kg and two doses of nivolumab 3mg/kg and underwent surgery within 6 weeks. In addition, patients with pMMR tumors were randomized to receive celecoxib. The primary endpoints were safety and feasibility, and secondary endpoints included pathologic response rate and disease-free survival in 30 patients with dMMR and 30 with pMMR tumors. Pathologic response was defined as 50% or less viable tumor rest (VTR), and major pathologic response (MPR) as <10% VTR. Results: Thirty patients with pMMR and 32 with dMMR tumors were evaluable for the efficacy analyses. In the pMMR cohort, pathologic response was observed in 9/30 (30%, 95% CI 14-46%) patients, consisting of 7 MPR (including 3 pathologic complete responses {pCR}) and 2 partial responses. Four out of 9 pMMR responders had received celecoxib. Five patients received adjuvant chemotherapy. At a median follow-up of 25 months (IQR 12-35 months), 3 patients (all non-responders) in the pMMR group had disease recurrence. In the 32 patients with dMMR tumors, pathologic response was observed in 100% of patients, with 31/32 MPR (97%, 95% CI 91-100%) and one partial response. Pathologic complete response was observed in 22/32 (69%, 95% CI 53-85%) patients. None of the patients in the dMMR cohort had disease recurrence. Surgery was delayed in one patient with a pMMR tumor due to myositis. Grade 3 immune-related adverse events were observed in 12% of patients, consistent with our previous report on the primary endpoint. There were no grade 4 immune-related AEs nor unexpected surgical complications. Conclusions: These data confirm our previously published results of the NICHE study, with responses to neoadjuvant nivolumab plus ipilimumab in 30% of pMMR and 100% of dMMR CC in the completed original cohorts. Validation of the dMMR responses in a large group of dMMR patients is ongoing and has the potential to change current practice. Clinical trial information: NCT03026140.

International validation of the Immunoscore-biopsy (ISB) to guide selection and monitoring of patients treated with watch-and-wait (WW) strategy for rectal cancer

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Background: The WW strategy for patients with rectal cancer who achieved a clinical complete response (cCR) after neoadjuvant therapy (nT) allows to avoid major resection and the associated morbidity and mortality. Standardized criteria to select and monitor WW patients, including biomarkers predicting recurrence after nT, are lacking. The prognostic impact of the immune infiltrate in colorectal cancers is now demonstrated and has been implemented into clinics through the Immunoscore, the first standardized digital-pathology-based assay, recommended by academic institutions. We evidenced that an Immunoscore adapted to biopsies (ISB) performed at diagnosis, predicts the response to nT and the risk of recurrence after nT. Its clinical utility was suggested in a test cohort of WW patients (El Sissy et al., Clin Cancer Res 2020). The aim of this study was to confirm the ability of the ISB to predict clinical outcomes, improve patients’ eligibility for the WW strategy, and optimize a follow-up schedule. Methods: A total of 304 WW patients from 10 centers across 7 countries were included. Tumor biopsies before treatment were immunostained for CD3+ and CD8+ T-cells and converted to ISB using the pre-defined cut-off. The primary endpoint was time-to-recurrence (TTR). Secondary endpoint was disease-free-survival (DFS). As immune response originates in draining lymph nodes, signs of immune activation were carried out in lymph nodes of additional patients managed by radical surgery with complete pathological response (pCR; n = 12) or non-pCR (n = 12) by 3' RNA-Seq and immunofluorescence technologies. Results: High-ISB patients presented with the lowest risk of recurrence after WW. 5-year recurrence-free rates were 97% (92%-100%), 61% (49%-76%), and 56% (44%-73%) with ISB High, Intermediate, and Low, respectively (HR [Low-vs-High] = 14.3, 95% CI 1.8-100). In patients with cCR after nT (n = 209), High-ISB showed a significant association with prolonged TTR and DFS (Logrank P = 0.005 and P = 0.006, respectively). When ISB was evaluated as a continuous variable, the risk of recurrence was increasing along with decreasing ISB (Wald tests, all P < 0.005). In multivariate analyses, ISB was independent of age, sex, location, and cTNM stage and was the single parameter correlated with TTR (HR [ISB High-vs-Low] = 0.08, 95% CI 0.01-0.6; P = 0.015) and DFS (P = 0.013). Unlike for patients with cCR, no difference according to ISB was observed for those with incomplete response (n = 41) or treated with brachytherapy (n = 34). Finally, intranodal signs of T-cell and B-cell activation were only evidenced in patients with pCR. Conclusions: ISB provides a reliable biomarker to predict clinical outcomes, improve eligibility, and optimize patients’ follow-up. Intranodal T-cell and B-cell activation further supports the immune benefit of both organ and lymph node preservation.

Guidelines on acute gastroenteritis in children: a critical appraisal of their quality and applicability in primary care

BACKGROUND

Reasons for poor guideline adherence in acute gastroenteritis (AGE) in children in high-income countries are unclear, but may be due to inconsistency between guideline recommendations, lack of evidence, and lack of generalizability of the recommendations to general practice. The aim of this study was to assess the quality of international guidelines on AGE in children and investigate the generalizability of the recommendations to general practice.

METHODS

Guidelines were retrieved from websites of professional medical organisations and websites of institutes involved in guideline development. In addition, a systematic search of the literature was performed. Articles were selected if they were a guideline, consensus statement or care protocol.

RESULTS

Eight guidelines met the inclusion criteria, the quality of the guidelines varied. 242 recommendations on diagnosis and management were found, of which 138 (57%) were based on evidence.There is a large variety in the classification of symptoms to different categories of dehydration. No signs are generalizable to general practice.It is consistently recommended to use hypo-osmolar ORS, however, the recommendations on ORS-dosage are not evidence based and are inconsistent. One of 14 evidence based recommendations on therapy of AGE is based on outpatient research and is therefore generalizable to general practice.

CONCLUSIONS

The present study shows considerable variation in the quality of guidelines on AGE in children, as well as inconsistencies between the recommendations. It remains unclear how to asses the extent of dehydration and determine the preferred treatment or referral of a young child with AGE presenting in general practice.