Immune checkpoint inhibitors for POLE or POLD1 proofreading-deficient metastatic colorectal cancer

BACKGROUND

POLE and POLD1 proofreading deficiency (POLE/D1pd) define a rare subtype of ultramutated metastatic colorectal cancer (mCRC; over 100 mut/Mb). Disease-specific data about the activity and efficacy of immune checkpoint inhibitors (ICIs) in POLE/D1pd mCRC are lacking and it is unknown whether outcomes may be different from mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) mCRCs treated with ICIs.

PATIENTS AND METHODS

In this global study, we collected 27 patients with mCRC harboring POLE/D1 mutations leading to proofreading deficiency and treated with anti-programmed cell death-ligand 1 alone +/- anti-cytotoxic T-lymphocyte antigen-4 agents. We collected clinicopathological and genomic characteristics, response, and survival outcomes after ICIs of POLE/D1pd mCRC and compared them with a cohort of 610 dMMR/MSI-H mCRC patients treated with ICIs. Further genomic analyses were carried out in an independent cohort of 7241 CRCs to define POLE and POLD1pd molecular profiles and mutational signatures.

RESULTS

POLE/D1pd was associated with younger age, male sex, fewer RAS/BRAF driver mutations, and predominance of right-sided colon cancers. Patients with POLE/D1pd mCRC showed a significantly higher overall response rate (ORR) compared to dMMR/MSI-H mCRC (89% versus 54%; P = 0.01). After a median follow-up of 24.9 months (interquartile range: 11.3-43.0 months), patients with POLE/D1pd showed a significantly superior progression-free survival (PFS) compared to dMMR/MSI-H mCRC [hazard ratio (HR) = 0.24, 95% confidence interval (CI) 0.08-0.74, P = 0.01] and superior overall survival (OS) (HR = 0.38, 95% CI 0.12-1.18, P = 0.09). In multivariable analyses including the type of DNA repair defect, POLE/D1pd was associated with significantly improved PFS (HR = 0.17, 95% CI 0.04-0.69, P = 0.013) and OS (HR = 0.24, 95% CI 0.06-0.98, P = 0.047). Molecular profiling showed that POLE/D1pd tumors have higher tumor mutational burden (TMB). Responses were observed in both subtypes and were associated with the intensity of POLE/D1pd signature.

CONCLUSIONS

Patients with POLE/D1pd mCRC showed more favorable outcomes compared to dMMR/MSI-H mCRC to treatment with ICIs in terms of tumor response and survival.

Waiting for the "liquid revolution" in the adjuvant treatment of colon cancer patients: a review of ongoing trials

Since colon cancer has a high rate of shedding of tumour fragments into the blood, several research efforts are now focused on the investigation of the minimal residual disease through the detection of ctDNA to tailor the adjuvant therapy of colon cancer patients and optimize its cost/effectiveness balance. The negative prognostic impact of detectable ctDNA in patients' blood after radical surgery for colon cancer is well established. Several clinical trials adopting heterogeneous designs and techniques are now ongoing to translate promises into daily practice by answering five general questions: i) is a ctDNA-guided decision making efficacious in the post-operative management of colon cancer patients? ii) are de-escalation strategies possible in ctDNA-negative cases? iii) are escalation strategies useful to improve the prognosis of ctDNA-positive patients? iv) when MRD is identified at the end of the adjuvant chemotherapy, is another post-adjuvant systemic therapy efficacious? v) can we exploit ctDNA technologies in the follow up of colon cancer patients? This review focuses on currently ongoing trials and how their results may affect the ctDNA "liquid revolution" of early colon cancer.

Predicting early recurrence after resection of initially unresectable colorectal liver metastases: the role of baseline and pre-surgery clinical, radiological and molecular factors in a real-life multicentre experience

BACKGROUND

Advances in surgical techniques and systemic treatments have increased the likelihood of achieving radical surgery and long-term survival in metastatic colorectal cancer (mCRC) patients with initially unresectable colorectal liver metastases (CRLMs). Nonetheless, roughly half of the patients resected after an upfront systemic therapy experience disease relapse within 6 months from surgery, thus leading to the question whether surgery is actually beneficial for these patients.

MATERIALS AND METHODS

A real-world dataset of mCRC patients with initially unresectable liver-limited disease treated with conversion chemotherapy followed by radical resection of CRLMs at three high-volume Italian institutions was retrospectively assessed with the aim of investigating the association of baseline and pre-surgical clinical, radiological and molecular factors with the risk of relapse within 6 or 12 months from surgery.

RESULTS

Overall, 268 patients were included in the analysis and 207 (77%) experienced recurrence. Ninety-six (46%) of them had disease relapse within 6 months after CRLM resection and in spite of several variables associated with early recurrence at univariate analyses, only primary tumour resection at diagnosis [odds ratio (OR) 0.53, 95% confidence interval (CI) 0.32-0.89, P = 0.02] remained significant in the multivariable model. Among patients with resected primary tumours, pN+ stage was associated with higher risk of disease relapse within 6 months (OR 3.02, 95% CI 1.23-7.41, P = 0.02). One hundred and forty-nine patients (72%) had disease relapse within 12 months after CRLMs resection but none of the analysed variables was independently associated with outcome.

CONCLUSIONS

Clinical, radiological and molecular factors assessed before and after conversion chemotherapy do not reliably predict early recurrence after secondary resection of initially unresectable CRLMs. While novel markers are needed to optimize the cost/efficacy balance of surgical procedures, CRLM resection should be offered as soon as metastases become resectable during first-line chemotherapy to all patients eligible for surgery.

Clinical impact of neutropenia and febrile neutropenia in metastatic colorectal cancer patients treated with FOLFOXIRI/bevacizumab: a pooled analysis of TRIBE and TRIBE2 studies by GONO

BACKGROUND

TRIBE and TRIBE-2 studies demonstrated higher benefit from FOLFOXIRI (fluorouracil, leucovorin, oxaliplatin, and irinotecan)/bevacizumab compared with FOLFIRI (fluorouracil, leucovorin, and irinotecan) or FOLFOX/bevacizumab as an upfront option for metastatic colorectal cancer patients, with more toxicities. We focused on the incidence and longitudinal dynamics of neutropenia and febrile neutropenia (FN) in the two studies, to evaluate their clinical relevance, the magnitude of impact of FOLFOXIRI/bevacizumab, and the role of risk factors in predicting their occurrence.

METHODS

The overall incidence of grade 3-4 (G3-4) neutropenia and FN, the time to their onset, the use of granulocyte colony-stimulating factor, and the association with risk factors were evaluated in the overall population and according to treatment arm. FN episodes were assessed by Multinational Association for Supportive Care in Cancer (MASCC) score.

RESULTS

Among 1155 patients, 568 (49%) received FOLFOXIRI/bevacizumab. Overall, 410 (35%) experienced G3-4 neutropenia and 70 (6%) FN, 21 (2%) at high risk. FOLFOXIRI/bevacizumab was associated with higher incidence of neutropenia (51% versus 21%, P < 0.001), FN (8% versus 4%, P = 0.02), and high-risk FN [18 (3%) versus 3 (1%), P = 0.015]. No related deaths were observed. The first episode of G3-4 neutropenia and FN occurred mainly in the first 2 months in both arms. Longitudinal analysis showed different patterns of evolution over cycles between the arms (P < 0.001) G3-4 neutropenia being more frequent in the first cycles with FOLFOXIRI/bevacizumab. Older patients (P = 0.01) and females (P < 0.001) had a significantly higher risk of G3-4 neutropenia. No significant interaction effect between arm and analysed risk factors in terms of risk of G3-4 neutropenia or FN was observed. The incidence of FN among older females receiving FOLFOXIRI/bevacizumab was 12%. Neither G3-4 neutropenia nor FN impaired efficacy in terms of overall response rate, progression-free survival, and overall survival.

CONCLUSIONS

FOLFOXIRI/bevacizumab has a higher risk of G3-4 neutropenia and FN than doublets/bevacizumab. FN occurred in <10% of patients, mostly as low-risk episodes. A closer monitoring during the first 2 months is recommended; prophylactic use of granulocyte colony-stimulating factor may be considered for older females.

A knowledge discovery framework to predict the N2O emissions in the wastewater sector

Data Analytics is being deployed to predict the dissolved nitrous oxide (N₂O) concentration in a full-scale sidestream sequence batch reactor (SBR) treating the anaerobic supernatant. On average, the N₂O emissions are equal to 7.6% of the NH₄-N load and can contribute up to 97% to the operational carbon footprint of the studied nitritation-denitritation and via-nitrite enhanced biological phosphorus removal process (SCENA). The analysis showed that average aerobic dissolved N₂O concentration could significantly vary under similar influent loads, dissolved oxygen (DO), pH and removal efficiencies. A combination of density-based clustering, support vector machine (SVM), and support vector regression (SVR) models were deployed to estimate the dissolved N₂O concentration and behaviour in the different phases of the SBR system. The results of the study reveal that the aerobic dissolved N₂O concentration is correlated with the drop of average aerobic conductivity rate (spearman correlation coefficient equal to 0.7), the DO (spearman correlation coefficient equal to -0.7) and the changes of conductivity between sequential cycles. Additionally, operational conditions resulting in low aerobic N₂O accumulation (<0.6 mg/L) were identified; step-feeding, control of initial NH₄⁺ concentrations and aeration duration can mitigate the N₂O peaks observed in the system. The N₂O emissions during aeration shows correlation with the stripping of accumulated N₂O from the previous anoxic cycle. The analysis shows that N₂O is always consumed after the depletion of NO₂^- during denitritation (after the "nitrite knee"). Based on these findings SVM classifiers were constructed to predict whether dissolved N₂O will be consumed during the anoxic and anaerobic phases and SVR models were trained to predict the N₂O concentration at the end of the anaerobic phase and the average dissolved N₂O concentration during aeration. The proposed approach accurately predicts the N₂O emissions as a latent parameter from other low-cost sensors that are traditionally deployed in biological batch processes.