A Review of Scheduling Strategies for Radiotherapy and Immune Checkpoint Inhibition in Locally Advanced Rectal Cancer

Colorectal cancer (CRC) is the third most common malignancy across the globe and, despite advances in treatment strategies, survival rates remain low. Rectal cancer (RC) accounts for most of these cases, and traditional management strategies for advanced disease include total neoadjuvant therapy (TNT) with chemoradiotherapy followed by curative surgery. Unfortunately, approximately 10-15% of patients have no response to treatment or have recurrence at a short interval following radiotherapy. The introduction of immunotherapy in the form of immune checkpoint blockade (ICB) in metastatic colorectal cancer has improved clinical outcomes, yet most patients with RC present with microsatellite stable disease, which lacks the immune-rich microenvironment where ICB is most effective. There is evidence that combining radiotherapy with ICB can unlock the mechanisms that drive resistance in patients; however, the sequencing of these therapies is still debated. This review offers a comprehensive overview of clinical trials and preclinical models that use radiotherapy-immunotherapy combinations in RC in an attempt to extrapolate the ideal sequencing of the two treatment modalities. The results highlight the dearth of evidence to answer the question of whether ICB should be given before, during, or after radiotherapy, yet it is suggested that improving the relevance of our preclinical models will provide a platform with higher translational value and will lead to appropriate clinical trial designs.

Efficacy and Safety of 4-Weekly Docetaxel for Castration-Resistant Prostate Cancer

We investigated the efficacy and safety profiles of 4-weekly docetaxel for castration-resistant prostate cancer. Patients treated with ≥2 courses of docetaxel chemotherapy (median, 70 mg/m²) between 2008 and 2018 were included. Among 125 Japanese men, 40 (32.0%) and 85 (68.0%) were treated with 3-weekly and 4-weekly regimens, respectively. In the 4-weekly regimen, the risks of progression, treatment failure, and any-cause mortality were comparable to those in the 3-weekly regimen. The incidences of severe adverse events were also similar between the 3-weekly and 4-weekly regimens. These data suggest that the 4-weekly regimen may be an acceptable option for selected patients.

Treatment of keloids with a single dose of low-energy superficial X-ray radiation to prevent recurrence after surgical excision: An in vitro and in vivo study

BACKGROUND

Although keloids have been empirically treated with steroids and radiation, evidence-based radiation parameters for keloid therapy are lacking.

OBJECTIVE

To determine evidence-based radiation parameters for blocking keloid fibroblast proliferation in vitro and apply them to patients.

METHODS

The effects of various radiation parameters and steroids on cell proliferation, cell death, and collagen production in keloid explants and fibroblasts were evaluated with standard assays. Effective radiation parameters were then tested on patients.

RESULTS

No differences were observed between the effects of 50 and 320 kV radiation or between single and fractionated radiation doses on keloid fibroblasts. A 3 Gy, 50 kV dose inhibited keloid fibroblast proliferation in culture, whereas 9 Gy completely blocked their outgrowth from explants by inducing multiple cell death pathways and reducing collagen levels. Thirteen of 14 keloids treated with a single 8 Gy, 50 kV dose of radiation did not recur, although 4 patients with 6 keloids were lost to follow-up.

LIMITATIONS

Seventy-five percent of patients received steroids for pruritus, whereas approximately 25% of patients were lost to follow-up.

CONCLUSIONS

A single 8 Gy dose of superficial 50 kV radiation delivered an average of 34 days after keloid excision maybe sufficient to minimize recurrence, including in individuals resistant to steroids. Higher radiation energies, doses, or fractions may be unnecessary for keloid therapy.

Drug-Drug Interactions of Irinotecan, 5-Fluorouracil, Folinic Acid and Oxaliplatin and Its Activity in Colorectal Carcinoma Treatment

The combination of folinic acid, 5-fluorouracil, oxaliplatin and/or irinotecan (FOLFOXIRI) is the standard of care for metastatic colorectal cancer (CRC). This strategy inhibits tumor growth but provokes drug resistance and serious side effects. We aimed to improve FOLFOXIRI by optimization of the dosing and the sequence of drug administration. We employed an orthogonal array composite design and linear regression analysis to obtain cell line-specific drug combinations for four CRC cell lines (DLD1, SW620, HCT116, LS174T). Our results confirmed the synergy between folinic acid and 5-fluorouracil and additivity, or even antagonism, between the other drugs of the combination. The drug combination administered at clinical doses resulted in significantly higher antagonistic interactions compared to the low-dose optimized drug combination (ODC). We found that the concomitant administration of the optimized drug combination (ODC) was comparatively active to sequential administration. However, the administration of oxaliplatin or the active metabolite of irinotecan seemed to sensitize the cells to the combination of folinic acid and 5-fluorouracil. ODCs were similarly active in non-cancerous cells as compared to the clinically used doses, indicating a lack of reduction of side effects. Interestingly, ODCs were inactive in CRC cells chronically pretreated with FOLFOXIRI, suggesting the occurrence of resistance. We were unable to improve FOLFOXIRI in terms of efficacy or specificity. Improvement of CRC treatment should come from the optimization of targeted drugs and immunotherapy strategies.

Appropriate Sequence for Afatinib and Cisplatin Combination Improves Anticancer Activity in Head and Neck Squamous Cell Carcinoma

Despite a better understanding in head and neck tumors pathogenesis as well as improvements in radiotherapy and surgery, locally advanced head and neck squamous cell carcinoma (HNSCC) remains of poor prognosis. One promising target is the epidermal growth factor receptor (EGFR), which is overexpressed in the majority of HNSCC and is associated to tumor progression and resistance to treatment. However, in several clinical trials, the combination of EGFR inhibitors with chemotherapy and/or radiotherapy generates moderate results. In this study, we investigated the anti-tumor activity of afatinib, an irreversible pan-EGFR inhibitor, combined to cisplatin in different schedules of exposure. For that, we used two human EGFR wild-type HNSCC cell lines and we evaluated the cytotoxicity of the two drugs combined in different sequences. The efficiency of each strategy was assessed by evaluating the effects on cell cycle distribution, DNA damage, cell death and downstream pathways of ErbB family receptors. We demonstrated that cisplatin treatment followed by afatinib exposure displayed more cytotoxic effects than the opposite timing or than simultaneous association. This higher anticancer activity is probably due to afatinib-induced cell cycle arrest, which prevents the repair of cisplatin-induced DNA damage and promotes cell death by various mechanisms including apoptosis. These data suggest the importance of an appropriate timing administration between an EGFR inhibitor and a conventional chemotherapy in order to obtain the best clinical benefit for patients with a head and neck cancer.

Computational design of treatment strategies for proactive therapy on atopic dermatitis using optimal control theory

Atopic dermatitis (AD) is a common chronic skin disease characterized by recurrent skin inflammation and a weak skin barrier, and is known to be a precursor to other allergic diseases such as asthma. AD affects up to 25% of children worldwide and the incidence continues to rise. There is still uncertainty about the optimal treatment strategy in terms of choice of treatment, potency, duration and frequency. This study aims to develop a computational method to design optimal treatment strategies for the clinically recommended 'proactive therapy' for AD. Proactive therapy aims to prevent recurrent flares once the disease has been brought under initial control. Typically, this is done by using an anti-inflammatory treatment such as a potent topical corticosteroid intensively for a few weeks to 'get control', followed by intermittent weekly treatment to suppress subclinical inflammation to 'keep control'. Using a hybrid mathematical model of AD pathogenesis that we recently proposed, we computationally derived the optimal treatment strategies for individual virtual patient cohorts, by recursively solving optimal control problems using a differential evolution algorithm. Our simulation results suggest that such an approach can inform the design of optimal individualized treatment schedules that include application of topical corticosteroids and emollients, based on the disease status of patients observed on their weekly hospital visits. We demonstrate the potential and the gaps of our approach to be applied to clinical settings.This article is part of the themed issue 'Mathematical methods in medicine: neuroscience, cardiology and pathology'.

Clinical and biological significance of erlotinib therapy after pemetrexed in non-small cell lung cancer with wild-type EGFR

Pemetrexed is a multi-targeted anti-folate agent that confers favorable benefits to patients with non-small cell lung cancer (NSCLC). However, the optimal use including treatment schedule of pemetrexed and other drugs in clinical practice remains to be determined, particularly for NSCLC with wild-type epidermal growth factor receptor (EGFR). The present study investigated a potential therapeutic strategy for NSCLC patients with wild-type EGFR who were treated with pemetrexed. To identify factors associated with a survival, medical record data from 130 patients were retrospectively reviewed, using the Kaplan-Meier method with log-rank test. Factors identified in the clinical analysis were further investigated within in vitro studies. Patients who underwent the treatment schedule of erlotinib at the time of progression after pemetrexed-based chemotherapy prolonged overall survival, compared to those treated with other schedules (p=0.010; hazard ratio, 0.418). This survival benefit was also observed in the treatment schedule of pemetrexed monotherapy and subsequent erlotinib (p=0.008; hazard ratio, 0.220). As a treatment at the time of progression after pemetrexed-based chemotherapy, erlotinib conferred a survival benefit when compared to docetaxel (p=0.024; hazard ratio, 0.377). The cell growth assay confirmed that treatment with pemetrexed followed by erlotinib significantly inhibited proliferation of NSCLC cells regardless of EGFR mutation status. In conclusion, use of erlotinib at the time of progression after pemetrexed therapy confers a survival benefit in NSCLC patients with wild-type EGFR. The result of this study provides an important clue to the optimal treatment schedule for NSCLC.

Sunitinib administered on 2/1 schedule in patients with metastatic renal cell carcinoma: the RAINBOW analysis

BACKGROUND

First-line sunitinib is recommended in metastatic renal cell carcinoma (mRCC), but it is frequently associated with relevant toxicities and subsequent dose reductions. Alternative schedules, such as 2-week-on treatment and 1-week-off (2/1 schedule), might improve tolerability. We evaluated the safety and outcomes of this schedule in a large multicenter analysis.

PATIENTS AND METHODS

Retrospective, multicenter analysis of mRCC patients treated with first-line sunitinib on a 2/1 schedule. Data of 249 patients were reviewed: 208 cases who started sunitinib on the 4/2 schedule (full dosage: 188/208, 90.4%) and thereafter switched to the 2/1 schedule for toxicity (group 4/2 → 2/1) and 41 patients who started first-line sunitinib with the 2/1 schedule because of suboptimal clinical conditions (group 2/1). A total of 211 consecutive patients treated with the 4/2 schedule in another institution served as external controls. Safety was the primary end point. Treatment duration (TD), progression-free survival (PFS) and overall survival (OS) were also analyzed.

RESULTS

In group 4/2 → 2/1, the overall incidence of grade ≥ 3 toxicities was significantly reduced (from 45.7% to 8.2%, P < 0.001) after the switch to 2/1 schedule. This advantage was maintained also in the 106/188 cases (56.4%) who maintained the full dosage. Fatigue, hypertension, hand-foot syndrome and thrombocytopenia were less frequent. The incidence of grade ≥ 3 adverse events in the negatively selected group 2/1 (only 73.2% starting at full dose) was 26.8%, similar to what observed in the external control group (29.4%). Median TD was 28.2 months in the 4/2 → 2/1 group (total time spent with both schedules), 7.8 months in the 2/1 group and 9.7 months in external controls. Median PFS was 30.2, 10.4 and 9.7 months, respectively. Median OS was not reached, 23.2 and 27.8 months, respectively.

CONCLUSIONS

mRCC patients who moved to a modified 2/1 schedule of sunitinib experience an improved safety profile compared with that observed during the initial 4/2 schedule.

Immunotherapy of Lewis lung carcinoma with hydrosoluble peptidoglycan monomer (PGM)

The water-soluble peptidoglycan monomer (PGM) isolated from the culture fluid of Brevibacterium divaricatum, which has immunostimulating activity, has been examined for its antitumor effects in C57BL mice bearing Lewis lung carcinoma. The formation of spontaneous lung metastases from SC tumor implants is significantly inhibited. The growth of SC primary tumors, including advanced ones, is also significantly inhibited, though to a less pronounced extent than the growth of metastases. The effects on metastases are evident with all treatment schedules used, whereas those on SC primary tumors are treatment schedule-dependent. The treatment with PGM was found to be therapeutically useful when combined with surgical removal of IM implants; in conditions where a single post-operative treatment was ineffective, combined post-operative and immediately pre-operative administration of PGM significantly increased (by 40%) the survival time of treated animals over that of controls undergoing surgery only.