Concurrent Radiotherapy Research Articles

Concurrent Use of Trastuzumab Deruxtecan and Radiation Therapy in HER2-positive and HER2-low Metastatic Breast Cancer: A Single-center Experience and Review of the Literature.

Recent DESTINY-Breast trials have demonstrated trastuzumab deruxtecan's effectiveness in HER2-positive and HER2-low metastatic breast cancer. However, safety concerns remain regarding its combination with radiation therapy (RT). The purpose of this work is to assess the toxicity profile of combining trastuzumab deruxtecan and RT in patients with HER2-positive and HER2-low metastatic breast cancer to address these concerns. We conducted a retrospective study which included patients treated at Institut Curie Paris between November 2020 and January 2024. Patients with HER2-positive and HER2-low metastatic breast cancer who received concurrent trastuzumab deruxtecan and RT were identified. Data on patient demographics, treatment regimens, radiation doses, toxicity profiles, and treatment discontinuations were collected. Follow-up was conducted from the last day of radiotherapy until death or the last examination and toxicities were graded using the CTCAE V5.0. The studied population includes all 33 patients with HER2-positive and HER2-low metastatic breast cancer who underwent concurrent treatment with trastuzumab deruxtecan and radiotherapy. The median follow-up was 11 months. The most common acute grade 1 toxicity was nausea. Grade 2 toxicities affected 21.2% of patients, including asthenia, mucositis, cardiac decompensation, and diarrhea. Trastuzumab deruxtecan discontinuation occurred in 5 patients due to systemic treatment-related toxicities, including nausea, thrombocytopenia, neutropenia, and cardiac decompensation. There were 21.2% reported with late toxicities, with nausea being the most prevalent. Our series of patients who received concurrent treatment of radiotherapy and trastuzumab deruxtecan are showing acceptable toxicity. Larger prospective studies are needed to evaluate the toxicity and efficacy of this combination.

Capecitabine or Capecitabine Plus Oxaliplatin Versus Fluorouracil Plus Cisplatin in Definitive Concurrent Chemoradiotherapy for Locally Advanced Esophageal Squamous Cell Carcinoma (CRTCOESC): A Multicenter, Randomized, Open-Label, Phase 3 Trial.

This phase 3 trial aimed to compare the efficacy and safety of capecitabine or capecitabine plus oxaliplatin (XELOX) with those of fluorouracil plus cisplatin (PF) in definitive concurrent chemoradiotherapy (DCRT) for inoperable locally advanced esophageal squamous cell carcinoma (ESCC). Patients were randomly assigned to receive two cycles of capecitabine, XELOX, or PF along with concurrent intensity-modulated radiation therapy. Patients in each arm were again randomly assigned to receive two cycles of consolidation chemotherapy or not. The primary end points were 2-year overall survival (OS) rate and incidence of grade ≥3 adverse events (AEs). A total of 246 patients were randomly assigned into the capecitabine (n = 80), XELOX (n = 85), and PF (n = 81) arms. In capecitabine, XELOX, and PF arms, the 2-year OS rate was 75%, 66.7%, and 70.9% (capecitabine v PF: hazard ratio [HR], 0.91 [95% CI, 0.61 to 1.35]; nominal P = .637; XELOX v PF: 0.86 [95% CI, 0.58 to 1.27]; P = .444); the median OS was 40.9 (95% CI, 34.4 to 49.9), 41.9 (95% CI, 28.6 to 52.1), and 35.4 (95% CI, 30.4 to 45.4) months. The incidence of grade ≥3 AEs during the entire treatment was 28.8%, 36.5%, and 45.7%, respectively. Comparing the consolidation chemotherapy with the nonconsolidation chemotherapy groups, the median OS was 41.9 (95% CI, 34.6 to 52.8) versus 36.9 (95% CI, 28.5 to 44) months (HR, 0.71 [95% CI, 0.52 to 0.99]; nominal P = .0403). Capecitabine or XELOX did not significantly improve the 2-year OS rate over PF in DCRT for inoperable locally advanced ESCC. Capecitabine showed a lower incidence of grade ≥3 AEs than PF did.

Analysis of tumor regression after concurrent radiochemotherapy for locally advanced hypopharyngeal carcinoma

Objective: To investigate the pathological characteristics of tumor regression and the expression level of chemoradiotherapy resistance-related molecular markers after preoperative concurrent radiochemotherapy in patients with locally advanced hypopharyngeal carcinoma. Methods: The clinical data of 44 patients with locally advanced hypopharyngeal carcinoma who underwent preoperative concurrent radiochemotherapy in the Department of Head and Neck Surgery of Shandong Otolaryngology Hospital from August 2016 to August 2020 were retrospectively analyzed. All patients received preoperative concurrent chemotherapy and radiotherapy. After radiochemotherapy, electronic laryngoscopy and imaging examination were performed to assess the tumor regression status. After 4 weeks, surgical resection was performed, and the specimens of the primary focus were processed as continuous pathological sections. After operation, HE staining and TdT-mediated dUTP nick-end labeling (TUNEL) method were used to detect the distribution characteristics and apoptosis of the remaining cancer focus, and immunohistochemistry was performed to determine the proliferation of the remaining cancer focus and the expression of radiation resistance-related molecular markers [signal transducer and activator of transcription 3 (STAT3), hypoxia-inducible factor-1alpha (HIF-1α), sex determining region Y-box 2 (SOX2), and P53]. Results: A total of 44 patients were included, all of whom were male, with a mean age of (58.3±3.5) years. There were 40 cases of pyriform sinus carcinoma and 4 cases of posterior pharyngeal wall carcinoma. Twenty-nine cases were in stage T3 and 15 cases were in stage T4. There were 6 stage Ⅲ cases and 38 stage Ⅳ cases. According to the response evaluation criteria in solid tumors (RECIST), 13 patients achieved complete response (CR), 22 patients had partial response (PR), and 9 patients achieved stable disease (SD) after concurrent radiochemotherapy. The primary lesion resection methods included 19 cases of hypopharyngeal circumferential resection and 2 cases of total laryngectomy and partial hypopharyngeal resection. Twenty-three cases underwent supracricoid cartilage subtotal laryngectomy cricoid tongue fixation (CHP). Among 22 patients with PR, 10 had large PR (remission rate ≥70%) and 12 had small PR (remission rate <70%). The residual tumor was found in 30 patients (68.2%) after resection of all primary lesions by HE staining of pathological sections, of which 3 patients (3/13) with CR had residual cancer, all of which were focal residues. In large PR patients, residual cancer was detected in 6 cases (6/10), scattered in 4 cases, and focal residual in 2 cases, respectively. Large residual tumors were detected in small PR and SD patients. TUNEL method did not show any sign of apoptosis in 30 specimens with residual cancer focus, and the positive expression rate of Ki-67 was less than 10%. The expression of STAT3 (3.40±2.49 vs 5.23±3.02, t=-2.932, P=0.007) in 19 cases (63.3%) and HIF-1α (3.73±2.66 vs 6.97±3.05, t=-4.45, P<0.001) in 22 cases (73.3%) of residual cancer were significantly higher than those before radiochemotherapy. Other molecular markers showed no significant changes. All patients were followed up for 3 years. The 2-year survival rate was 59.3%, and the 3-year survival rate was 54.1%. Conclusions: Preoperative radiochemotherapy can make some patients with locally advanced hypopharyngeal carcinoma achieve complete or significant remission in clinical evaluation, but pathological detection still shows some residual cancer lesions with enhanced anti-apoptosis ability and decreased proliferation activity.

Concurrent use of Radiotherapy and Ribociclib: Preliminary Results and Review of the Literature.

In the recent MONALEESA-2, MONALEESA-3, and MONALEESA-7 clinical trials, the addition of ribociclib, a CDK4/6 inhibitor, to standard endocrine therapy significantly improved progression-free survival (PFS) compared with hormone therapy alone in the treatment of locally advanced or metastatic estrogen receptor-positive (ER) and HER2-negative breast cancer. However, its toxicity raises concerns when administered concomitantly with radiotherapy, leading most radiotherapists and medical oncologists to prefer to discontinue Ribociclib during radiotherapy (RT). Although there are insufficient published data on this combination, our preliminary experience with the first 2 patients treated at Institut Curie suggests promising results when using Ribociclib with Letrozole or Fulvestrant concurrently with palliative radiotherapy in the treatment of metastatic breast cancer. Our study aimed to evaluate the safety of combining Ribociclib with palliative radiotherapy in patients with metastatic breast cancer, providing crucial insights for clinical decision-making. A retrospective analysis was conducted on patients treated for hormone receptor-positive metastatic breast cancer with Ribociclib and concurrent radiotherapy at the Institut Curie (Paris, France) between September 2023 and April 2024. Among 38 patients who received Ribociclib and underwent irradiation, 36 temporarily suspended Ribociclib during radiotherapy, while 2 continued Ribociclib concurrently and were included in the analysis. Palliative radiotherapy was administered using volumetric modulated arc therapy, delivering 20Gy in 5 fractions to bone metastatic sites. Ribociclib was given at 600mg/day with hormonotherapy. Follow-up was conducted from the last day of RT until the last medical consultation. Toxicities were graded using CTCAE V5.0. Two patients received Ribociclib concomitantly with radiotherapy, experiencing pain relief without interruptions in RT. However, Ribociclib treatment was halted in both cases due to grade 3 neutropenia and grade 1 QTc interval prolongation, respectively. One patient had a dose reduction to 400mg due to neutropenia, with favorable outcomes observed. Both patients continued Ribociclib treatment, with one achieving complete remission and the other partial remission of bone disease. No late toxicities were observed. Despite the need for further investigation, our results suggest safety consistent with pivotal trials, advocating for a prospective cooperative data collection initiative to explore this combined strategy further, potentially revolutionizing metastatic breast cancer management.

A high-throughput focused collimator for OAR-sparing preclinical proton FLASH studies: commissioning and validation

Objective. To fabricate and validate a novel focused collimator designed to spare normal tissue in a murine hemithoracic irradiation model using 250 MeV protons delivered at ultra-high dose rates (UHDRs) for preclinical FLASH radiation therapy (FLASH-RT) studies. Approach. A brass collimator was developed to shape 250 MeV UHDR protons from our Varian ProBeam. Six 13 mm apertures, of equivalent size to kV x-ray fields historically used to perform hemithorax irradiations, were precisely machined to match beam divergence, allowing concurrent hemithoracic irradiation of six mice while sparing the contralateral lung and abdominal organs. The collimated field profiles were characterized by film dosimetry, and a radiation survey of neutron activation was performed to ensure the safety of staff positioning animals. Main results. The brass collimator produced 1.2 mm penumbrae radiation fields comparable to kV x-rays used in preclinical studies. The penumbrae in the six apertures are similar, with full-width half-maxima of 13.3 mm and 13.5 mm for the central and peripheral apertures, respectively. The collimator delivered a similar dose at an average rate of 52 Gy s−1 for all apertures. While neutron activation produces a high (0.2 mSv h−1) initial ambient equivalent dose rate, a parallel work-flow in which imaging and setup are performed without the collimator ensures safety to staff. Significance. Scanned protons have the greatest potential for future translation of FLASH-RT in clinical treatments due to their ability to treat deep-seated tumors with high conformality. However, the Gaussian distribution of dose in proton spots produces wider lateral penumbrae compared to other modalities. This presents a challenge in small animal pre-clinical studies, where millimeter-scale penumbrae are required to precisely target the intended volume. Offering high-throughput irradiation of mice with sharp penumbrae, our novel collimator-based platform serves as an important benchmark for enabling large-scale, cost-effective radiobiological studies of the FLASH effect in murine models.

Tolerance of radiotherapy with concomitant glofitamab in diffuse large Bcell lymphoma: acase report.

Glofitamab, an anti-CD20 antibody, is approved as a third-line treatment for relapsed or refractory (r/r) diffuse large-cell B lymphoma (DLBCL), achieving a complete response in nearly 40% of patients. This humanized IgG1 bispecific monoclonal antibody binds to CD20 on malignant B lymphocytes and to CD3 on cytotoxic T cells. This dual binding forms an immunological synapse, activating T lymphocytes and leading to the lysis of tumor cells. Salvage radiotherapy is also effective for r/r DLBCL, but its combination with systemic treatments like glofitamab may increase radiation-induced toxicity. We report the first case of a patient with r/r DLBCL receiving concurrent salvage radiotherapy and glofitamab. A 68-year-old female diagnosed with stage IV DLBCL underwent initial treatment with R-CHOP, then Car-T cell therapy, followed by glofitamab for recurrence. Upon early metabolic progression detected by 18FDG-PET/CT, salvage radiotherapy was administered to the refractory site concurrently with glofitamab. The patient experienced mild para-spinal pain post-radiotherapy but no other significant toxicities. Three months post-treatment, she showed a complete metabolic response with no radiotherapy toxicity, as evidenced by PET-CT, and no signs of radiation pneumonitis. This case indicates that combining glofitamab with salvage radiotherapy is tolerable and suggests potential efficacy, warranting further investigation in prospective studies for r/r DLBCL.

Phase II, Single-Arm Trial of Induction and Concurrent Vismodegib With Curative-Intent Radiation Therapy for Locally Advanced, Unresectable Basal Cell Carcinoma.

Locally advanced, unresectable basal cell carcinoma (LA BCC) can be treated with radiation therapy (RT), but locoregional control (LRC) rates are unsatisfactory. Vismodegib is a hedgehog pathway inhibitor (HPI) active in BCC that may radiosensitize BCC. We evaluated the combination of vismodegib and RT for patients with LA BCC. In this multicenter, single-arm, phase II study, patients with unresectable LA BCC received 12 weeks of induction vismodegib, followed by 7 weeks of concurrent vismodegib and RT. The primary end point was LRC rate at 1 year after the end of treatment. Secondary end points included objective response, progression-free survival (PFS), overall survival (OS), safety, and patient-reported quality of life (PRQOL). Twenty-four patients received vismodegib; five were unable to complete 12 weeks of induction therapy. LRC was achieved in 91% (95% CI, 68 to 98) of patients at 1 year. The response rate was 63% (95% CI, 38 to 84) after induction vismodegib and 83% (95% CI, 59 to 96) after concurrent vismodegib and RT. With a median follow-up of 5.7 years, 1-year PFS and OS rates were 100% and 96%, and at 5 years PFS and OS rates were 78% and 83%, respectively. Distant metastasis or BCC-related death has not been observed. The most frequent treatment-related adverse events (AEs) were dysgeusia, fatigue, and myalgias occurring in 83%, 75%, and 75% of patients. No grade 4 to 5 treatment-related AEs occurred. PRQOL demonstrated clinically meaningful improvements in all subscales, with emotions and functioning improvements persisting for a year after the end of treatment. In patients with unresectable LA BCC, the combination of vismodegib and RT yielded high rates of LRC and PFS and durable improvements in PRQOL.

PPD01.09 Cardiac Events following Concurrent Chemotherapy and Radiation with Durvalumab Consolidation for Unresectable Non-metastatic Non-Small Cell Lung Cancer

PPD01.09 Cardiac Events following Concurrent Chemotherapy and Radiation with Durvalumab Consolidation for Unresectable Non-metastatic Non-Small Cell Lung Cancer

Optimizing Organ-Preservation Strategies Through Chemotherapy-Based Selection in Esophageal Squamous Cell Carcinoma: Results From the CROC Multi-Institutional Phase 2 Clinical Trial

PurposeThis study aimed to assess the viability of definitive chemoradiotherapy (dCRT) as an organ-preservation strategy for remarkable responders who were downstaged to stage IA after receiving induction chemotherapy for resectable esophageal squamous cell carcinoma (ESCC). Methods and MaterialsChemotherapy-naïve patients with resectable ESCC (stage IB–III, UICC, International Cancer Control 7th edition) were eligible for the study. All patients received three cycles of DCF therapy (docetaxel 75 mg/m2 on day 1, cisplatin 75 mg/m2 on day 1, and 5-fluorouracil [5-FU] 750 mg/m2 on days 1–5, repeated every three weeks). A remarkable response was defined as a reduction of the tumor to T1, metastatic lymph nodes smaller than 1 cm on the short axis, and downstaging to stage IA after three cycles of DCF therapy. Remarkable responders then underwent dCRT, which included two courses of cisplatin 75 mg/m2 and 5-FU 1000 mg/m2 on days 1–4, repeated every four weeks, along with 50.4 Gy of concurrent radiotherapy. The primary endpoint was 1-year progression-free survival (PFS) in remarkable responders following DCF therapy and subsequent dCRT. Secondary endpoints included 3-year overall survival (OS) and esophagectomy-free survival (EFS). ResultsOf the 92 patients registered, 90 were analyzed. A remarkable response to three courses of DCF therapy was observed in 58.4% of patients. Among these responders, 89.8% achieved a complete response after dCRT. During the median follow-up period of 33 months (range: 1–85 months), the 1-year PFS was 89.8% (95% confidence interval = 77.2%–95.6%, primary endpoint), and the 3-year OS was 83.7%. The 3-year OS and EFS rates in the analysis group were 74.1% and 45.3%, respectively. An 18F-fluorodeoxyglucose-positron emission tomography response after two courses of DCF therapy was significantly associated with OS (p = 0.0049). ConclusionsIn patients with resectable ESCC, dCRT for remarkable responders downstaging to stage IA after induction chemotherapy with three courses of DCF therapy is a feasible treatment option and provides an optimizing organ-preservation strategy of chemotherapy-based selection.

Effectiveness and safety of combined nimotuzumab and S-1 chemotherapy with concurrent radiotherapy for locally advanced esophageal cancer in malnourished and elderly patients: A prospective phase II study.

Definitive chemoradiotherapy (dCRT) is the standard treatment for unresectable locally advanced esophageal cancer. However, this treatment is associated with substantial toxicity, and most malnourished or elderly patients are unable to complete this therapy. Therefore, there is a need for a more suitable radiotherapy combination regimen for this population. This study was aimed to evaluate the efficacy and safety of a combination regimen comprising chemotherapy with nimotuzumab and S-1 and concurrent radiotherapy for patients with fragile locally advanced esophageal cancer with a high Nutritional Risk Screening 2002 (NRS-2002) score. Eligible patients with unresectable esophageal carcinoma who had an NRS-2002 score of 2 or higher were enrolled. They were treated with S-1 and nimotuzumab with concurrent radiotherapy, followed by surgery or definitive radiotherapy. The primary endpoint was the locoregional control (LRC) rate. A total of 55 patients who met the study criteria were enrolled. After completion of treatment, surgery was performed in 15 patients and radiotherapy was continued in 40 patients. The median follow-up period was 33.3 [95% confidence interval (95% CI), 31.4-35.1)] months. The LRC rate was 77.2% (95% CI, 66.6%-89.4%) at 1 year in the entire population. The overall survival (OS) rate and event-free survival (EFS) rate were 57.5% and 51.5% at 3 years, respectively. Surgery was associated with better LRC [hazard ratio (HR)=0.16; 95% CI, 0.04-0.70; P=0.015], OS (HR=0.19; 95% CI, 0.04-0.80; P=0.024), and EFS (HR=0.25; 95% CI, 0.08-0.75; P=0.013). Most adverse events were of grade 1 or 2, and no severe adverse events occurred. For malnourished or elderly patients with locally advanced esophageal cancer, radiotherapy combined with nimotuzumab and S-1 is effective and has a good safety profile.

A single arm phase 2 clinical trial of YIV-906 with neoadjuvant concurrent chemo-radiation therapy in patients with locally advanced rectal cancer.

Pre-operative chemoradiation for rectal cancer is often associated with severe gastrointestinal (GI) toxicity which can interrupt, delay, and/or lead to termination of treatment. In this study, we evaluated whether the addition of YIV-906, a novel herbal medicine proven to reduce GI toxicity associated with chemotherapy could also reduce GI side effects during standard pre-operative capecitabine and pelvic radiation therapy (RT) in the neoadjuvant setting for the treatment of locally advanced rectal cancer. This single arm clinical study enrolled 24 patients between Dec 23, 2014-Sep 17, 2018 at Smilow Cancer Hospital, a comprehensive cancer center at Yale New Haven Hospital. All patients were age ≥18 years, Eastern Cooperative Oncology Group 0-1 and with histologically confirmed T3-T4 and N0-N2, M0 adenocarcinoma of the rectum. Median follow-up was 61.9 months. All patients received concurrent pelvic external beam RT (50.4 Gy in 28 fractions), YIV-906 (taken orally 800 mg twice daily on days 1-4 of RT each week), and oral capecitabine delivered in a neo-adjuvant fashion, followed by definitive surgery. Toxicity was assessed weekly during radiation and until acute symptoms resolved and then at 28 days, 4 months, 7 months and 10 months. Toxicities were graded in accordance with Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. At the time of surgery, 4 patients (16.7%) had a complete or near-complete response. At a median follow-up of 61.9 months, the mean overall survival (OS) of our patient cohort was 74.9 months [95% confidence interval (CI): 67.3-82.5]. The estimated 5-year OS was 82.0%. We observed 0% acute grade 4 toxicities, and only two cases of acute grade 3 diarrhea (8.3%). The addition of YIV-906 to capecitabine based chemoradiation for locally advanced rectal cancer led to reduced rates of GI toxicity compared to historical controls, in particular grade 3 or greater diarrhea. These findings suggest YIV-906 should be evaluated in a randomized clinical trial to further assess potential reductions in the toxicity profile of chemoradiation for GI cancers.

Prospective clinical study of the efficacy and safety of different doses of PEG recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) for preventing leukopenia/neutropenia caused by concurrent chemoradiotherapy for cervical cancer

ObjectiveThe efficacy and safety of different doses of PEG recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) in the prevention of leukopenia/neutropenia during concurrent chemoradiotherapy for cervical cancer were investigated.MethodsThe patients who received concurrent radiotherapy and chemotherapy for cervical cancer from June 2020 to January 2023 were selected to evaluate the difference in efficacy, adverse reactions, and treatment cost of PEG-rhG-CSF in the prevention of leukopenia/neutropenia between the test group and the control group.ResultsThe minimum value of leukopenia/neutropenia in the test group was significantly higher than that in the control group (P < 0.05). The incidence of grade ≥ 3 leukopenia/neutropenia was significantly lower than that of the control group (P < 0.05). The number of interrupted days of radiotherapy was less than that of the control group (P < 0.05). PEG-rhG-CSF of different prophylactic doses (100 μg/kg dose or 50 μg/kg dose) had similar prophylactic effects in the test group, OR=1.192 (0.761, 1.868), P=0.443.ConclusionProphylactic application of PEG-rhG-CSF could reduce the incidence of leukopenia/neutropenia in cervical cancer during concurrent chemoradiotherapy. There was no significant difference in efficacy and safety with prophylactic use of drug at doses of 100 μg/kg and 50 μg/kg.

DIPG-41. CONVECTION ENHANCED DELIVERY-MEDIATED RADIOSENSITIZATION FOR DIFFUSE MIDLINE GLIOMA

Abstract BACKGROUND Diffuse midline glioma (DMG) is the most aggressive primary brain tumor in children. The only approved standard of care is radiation therapy (RT). Studies examining the role of other systemic agents have failed to demonstrate a survival benefit, partially due to tumor extension to areas of the brain where the blood-brain barrier (BBB) remains intact. As our laboratory has recently determined active NAD(P)H Quinone Dehydrogenase 1 (NQO1) expression in patient-derived DMG tumor samples, we sought to investigate NQO1 bioactivatable agent Napabucasin to augment reactive oxygen species (ROS) production and overcome radioresistance in DMG. Furthermore, we explore the safety and feasibility of convection-enhanced deliver (CED) to overcome limitations of the BBB. METHODS Using two DMG cell lines, we performed clonogenic survival assays with increasing doses of RT with and without Napabucasin. We then created subcutaneous xenograft mouse models, treating with (1) vehicle control, (2) Napabucasin, (3) 2 Gy of RT daily, or (4) combination treatment with RT and Napabucasin. Using a syngeneic orthotopic DMG mouse model, we implanted 7-day osmotic infusion pumps containing either vehicle control or 80uM Napabucasin. Mice then underwent a second randomization with or without daily RT for 5 days. RESULTS We identified a robust radiosensitizing effect with Napabucasin using in vitro clonogenic survival assays. In subcutaneous flank models, combination treatment led to a statistically significant smaller tumor volume post-treatment completion when compared to any monotherapy. In our syngeneic orthotopic DMG mouse model, RT after CED pump implantation in the brainstem did not lead to significant morbidity or mortality. Combination RT and CED of Napabucasin led to a significant survival benefit when compared to monotherapy. CONCLUSIONS In this study, we show Napabucasin as a promising radiosensitizer in DMG. Furthermore, this is the first preclinical study showing safety/efficacy of CED with concurrent RT in DMG.

DIPG-61. ARGININE DEPRIVATION USING ADI-PEG20 IMPROVES SURVIVAL IN A SYNGENEIC DIFFUSE MIDLINE GLIOMA MOUSE MODEL

Abstract BACKGROUND Diffuse midline glioma (DMG-H3K27) presents a significant challenge in paediatric oncology, with a &amp;lt;10% two-year survival rate despite standard palliative radiotherapy. Tumour infiltration behind the blood-brain barrier hampers drug delivery, contributing to clinical trial failures. ADI-PEG20 exploits tumour metabolic vulnerabilities: lack of argininosuccinate synthetase and reliability on extracellular arginine for proliferation. This study investigates ADI-PEG20’s efficacy in a syngeneic DMG mouse model. METHODS Twenty C57BL/6J mice were intracranially injected with a DMG cell line (H1H3BK27M, DNp53, PDGFRAD642V, Acvr1G328V) and monitored via bioluminescence imaging from day 7. Weekly treatments began on day 10, comprising ADI-PEG20 (5 I.U.) alone, ADI-PEG20 with concurrent radiation (2 Gy), radiation alone, or saline (0.9%), with each group comprising n=5. Radiation was administered 24 hours post-drug treatment. Bioluminescence imaging was conducted twice weekly, with mice culled upon symptom onset. Immunohistochemistry was performed on brain tissue. RESULTS The combination and ADI-PEG20 monotherapy cohorts exhibited comparable median survival rates, both surpassing those of the radiation-only and saline groups, with the latter exhibiting the lowest median survival. A significant disparity in survival curves was observed overall (p&amp;lt;0.0001), confirmed by log-rank (Mantel-Cox) test. Pairwise comparisons revealed significant differences in survival curves between the combination and radiation-only (p=0.0066), ADI-PEG20 monotherapy and radiation-only (p=0.0018), and ADI-PEG20 monotherapy and saline (p=0.0062) groups. Minimal divergence in IVIS signal intensity was noted across groups. Histological examination via H&amp;E staining demonstrated marked tumour regression in mice treated with ADI-PEG20 ± radiation, contrasting with the persistent tumour mass evident in the radiation-only and saline cohorts, alongside discernible heterogeneity in cellular phenotypes within the ADI-PEG20 ± groups. CONCLUSIONS In conclusion, ADI-PEG20 shows promise as a therapeutic strategy for DMG, offering a significant survival advantage over radiation and saline. Ongoing efforts will elucidate its mechanistic underpinnings, explore its efficacy across diverse DMG models, and assess synergistic interactions with immune-based therapies.

Audiological Outcomes of Weekly vs. Triweekly Cisplatin in Head and Neck Cancer with Cochlear-Sparing Intensity-Modulated Radiation Therapy.

Cisplatin, one of the most ototoxic anti-neoplastic agents, causes permanent hearing loss in up to 90% of patients. We assessed ototoxicity rates and prospectively collected audiologic outcomes of patients receiving low-dose or high-dose cisplatin with concurrent cochlear-sparing intensity-modulated radiation therapy (IMRT). Patients with head and neck squamous cell carcinoma (HNSCC) receiving definitive or adjuvant cisplatin-based chemoradiotherapy (CRT) were analyzed. Cisplatin was administered either in low doses weekly (40 mg/m2) for up to seven doses or in high doses triweekly (100 mg/m2) for up to three doses. Cochlear-sparing IMRT was delivered in all cases. Audiologic data were prospectively collected before, during, and after treatment completion. The primary endpoint was a hearing change grade of ≥3 after CRT completion. Of the 96 HNSCC patients evaluated, 69 received weekly cisplatin and 58 received definitive CRT. Of patients receiving weekly cisplatin, 13% developed ≥G3 ototoxicity vs. 56% of patients who received triweekly cisplatin (p < 0.001). In multivariable modeling, the cisplatin dose schedule remained significant (OR: 8.4, 95%CI: 2.8-27.8, p < 0.001) for risk of severe irreversible ototoxicity. Triweekly cisplatin CRT significantly increased the ≥G3 severe irreversible ototoxicity risk compared to low-dose weekly cisplatin, irrespective of the cumulative cisplatin dose, even with the use of cochlear-sparing IMRT. No significant difference in oncologic outcomes was observed between the two schedules.

Long term results of a randomized phase III study of nimotuzumab in combination with concurrent radiotherapy and cisplatin versus radiotherapy and cisplatin alone, in locally advanced squamous cell carcinoma of the head and neck.

LBA6092 Background: The addition of nimotuzumab to weekly cisplatin as a radiosensitizer had improved progression-free survival (PFS) in a phase 3 study in locally advanced head and neck squamous cell carcinoma (LA HNSCC). However, whether it leads to an improvement in long-term OS is unknown. Hence this analysis was performed to evaluate the efficacy (in terms of OS) and late-term adverse events of the addition of nimotuzumab to concurrent chemoradiation in LA HNSCC. Methods: This was an open-label, investigator-initiated, phase 3 randomized trial conducted from 2012 - 2018. 536 adult patients with LA HNSCC, fit for radical chemoradiation were randomly assigned. Primary sites in the nasopharynx, salivary gland, nasal cavity, and paranasal sinus were excluded. Randomized 1:1 to either radical radiotherapy (66-70 Gy) with concurrent weekly cisplatin (30 mg/m2) (CRT) or the same schedule of chemoradiation with weekly nimotuzumab (200 mg) (NCRT). The primary endpoint was a 10-year OS; the key secondary endpoint was late adverse events. Intent to treat analysis was performed. OS was defined as the time from randomization till death. Kaplan Meier method will be used for the estimation of OS. Landmark analysis was performed to compare 10 OS between the 2 arms. COX proportional hazard model will be used for the calculation of hazard ratio (HR). The adverse events between the 2 arms were compared using a Fisher's test. A p-value of 0.05 will be considered as significant. Results: The median follow-up was 8.86 years (95% CI 8.59-9.16). The primary site of the primary was the oropharynx (269,50.2%) and only 24 cases were HPV positive. The 10-year OS was 22.5% (95% CI 16.7-28.8) versus 33.5% (95% CI 27.6-39.4) in the CRT and NCRT arm respectively (Hazard ratio=0.811; 95%CI 0.664-0.995, P=0.044). The median OS was 2.78 years (95% CI 2.31-3.69) versus 3.69 years (95% CI 2.90-4.49) in the CRT and NCRT arm respectively (P value by log-rank test=0.04). The median OS in HPV negative oropharynx was 1.8 years (95% CI 1.51-2.09) versus 2.48 years (95% CI 1.79-3.16) in the CRT and NCRT arm respectively (P value by log-rank test=0.02; HR 0.724 95%CI 0.546-0.959). Long-term adverse events were captured in 380 patients. There was no statistically significant difference in late-term adverse events between the 2 arms and will be presented at the conference. Conclusions: The addition of nimotuzumab to weekly cisplatin leads to improvement in long-term overall survival in locally advanced HNSCC without any additional increase in late-term adverse events. These results are largely applicable in HPV-negative patients. Clinical trial information: CTRI/2014/09/004980 .

Survival outcomes of concurrent radiotherapy and toripalimab versus radiotherapy alone for elderly patients with postoperative head and neck squamous cell carcinoma unfit for cisplatin.

6099 Background: For elderly patients with locally advanced head and neck squamous cell carcinoma (HNSCC), the role of postoperative concurrent chemotherapy was controversial since the intolerable toxicities and increased acute mortality, thus, radiotherapy alone was recommended. We aimed to assess if addition of toripalimab (anti-PD-1) to radiotherapy could improve treatment outcomes for this patient population. Methods: This trial was an, open-label, phase 2, randomized study.We randomly assigned (1:1) patients aged&gt;65 years, with ECOG Performance Status(PS) of 0–2, and with postoperative Stage III-IV (AJCC 8th Staging system) HNSCC unfit for cisplatin to concurrent radiotherapy (60-66Gy) and toripalimab (240mg on D0, D21 and D42)(RT+PD-1 group) or radiotherapy alone(RT group). The primary endpoint was 2-year disease free survival (DFS). It is hypothesized to detect a difference between arms of 45%-65% in 2-year DFS. Results: Between September 2020 and May 2023, 87 patients were randomly assigned (43 in RT+PD-1 group and 44 in RT group). The median age were 71.0 years (range 66-81) for the RT+PD-1 group and 72.5 years (range 67-80 years) for RT group. In the RT+PD-1 group, 35 (81.4%) patients received at least one dose of toripalimab; 38 (88.3%) patients in the RT+PD-1 group and 36 (81.8%) patients in the RT group complete the planed radiation dose. Median follow-up was 24 months in both arms. The 2-year DFS was 55.3% with RT+PD-1 and 51.2% with RT alone (p=0.866), and the 2-year OS was 63.3% with RT+PD-1 and 78.4% with RT alone(p=0.557). In RT+PD-1 group, 18(41.8%) patients were CPS≥20%; 2-year DFS was 72.2% in patients with CPS≥20%, which was 53.8% in patients with CPS&lt;20 (p=0.412). Conclusions: The primary objective of prolonging DFS with concurrent radiotherapy and toripalimab in elderly patients unfit for cisplatin with locally advanced HNSCC was not met. For patients with CPS≥20, further study still warranted to evaluate the benefit of toripalimab in this patient setting. Biomarker analysis is still ongoing. Clinical trial information: NCT04523883 .

Efficacy and safety of concurrent capecitabine and radiotherapy as adjuvant treatment in triple negative breast cancer.

e12534 Background: Triple-negative breast cancer remains a very aggressive disease with few treatments option. Neoadjuvant dose dense chemotherapy, adjuvant therapy with capecitabine for residual disease and radiotherapy are standard treatments. The aims of this study were to evaluate the efficacy and safety of capecitabine concurrent with radiotherapy in initially clinical stage III patients with triple negative breast cancer in order to improve locoregional control and survival of these patients. Methods: We prospectively analyzed 24 patients with triple negative breast cancer with residual disease after dose dense neoadjuvant chemotherapy with Epirubicin and Cyclophosphamide and Docetaxel (in some cases with carboplatin) who received concurrent Capecitabine and radiotherapy in adjuvant setting. External beam radiotherapy to the hole breast was administered at a dose of 45–50.4 Gy in 25–28 fractions, concurrent with Capecitabine 825 mg/m2, 5 days/week. Results: Median age at diagnostic was 47.1±7.4. Stage distribution was as followed: 45.8% stage IIIA, 25% stage IIIB and 29.2% stage IIIC. Median follow-up was 31 months. Median Disease-Free Survival (DFS) was 48 months, with 76%, 68%, and 46% of patients without recurrence at 24, 36 and 48 months respectively. All patients presented with distant relapses. Median overall survival (OS) was not reached, and 3 years survival rate was 88%. Most common toxicities of concurrent radiotherapy and capecitabine were radiation dermatitis all grades in 100% of patients, grade 3 in 37.5% and grade 4 in 4.1%. Other side effects were neutropenia grade 4 in 8.3% and lymphopenia grade 4 in 45.8% of patients. Conclusions: Capecitabine concurrent with radiotherapy appears to be very efficacious and safe in the adjuvant treatment of breast cancer, especially in preventing local recurrence.

Real-world safety and efficacy of concurrent immunotherapy and thoracic chemoradiotherapy: A multi-institutional analysis.

e23262 Background: Despite the success of Immune checkpoint inhibitors (ICIs) as consolidation following concurrent chemoradiotherapy (CCRT), 22% to 30% of patients still cannot be treated with durvalumab due to progression or adverse events (AEs) during or after CCRT. Concurrent ICIs with CCRT would offer the opportunity to receive ICIs and may provide treatment benefit to a greater proportion of patients. In this study, we performed a multicenter investigation to evaluate the safety and efficacy of ICIs and chemotherapy with concurrent thoracic radiotherapy. Methods: All patients from three institutions who underwent ICIs and concurrent thoracic radiotherapy were included. The rate of 12-month progression-free survival (PFS) was estimated using the Kaplan-Meier method and evaluated with 95% CIs calculated using the Greenwood formula. Therapy-related pneumonitis (TRP) and esophagitis (TRE) were defined per CTCAE v5.0. Statistics utilized logistic regression modeling and receiver operating characteristic (ROC) analysis. Results: 69 patients (median [range] age, 62 [52-76]; 61 [88.4%] male; median follow-up 30.4 months) were collected, including 18 (26.1 %) cases of non-small cell lung cancer (NSCLC), 26 (37.7 %) cases of small cell lung cancer (SCLC), and 25 (36.2 %) cases of esophageal cancer (EC). The 12-month PFS rates in NSCLC, SCLC and EC were 72.2%, 69.2% and 72.0%, respectively. The median PFS in NSCLC and SCLC was 24.3 and 13.1 months, and not reached (mean 29 months) for EC. The incidences of all-grade TRP and TRE were 60.7% and 57.7%, respectively. Grades 1-5 TRP occurred in 15.9%, 30.4%, 8.6%, 1.4%, and 0, respectively. Grades 1-5 TRE occurred in 20.2%, 28.9%, 8.6%, 0, and 0, respectively. On multivariable analysis, age and MLD significantly predicted for any-grade and grade ≥2 TRP. Only age significantly predicted for grade ≥3 TRP. ROC analysis was able to pictorially model RP risk probabilities for a variety of MLD and age thresholds. Conclusions: This real-world study can be helpful for understanding the true efficacy and toxicity of ICIs and chemotherapy with concurrent thoracic radiotherapy given the lack of robust clinical data. Close monitoring should be recommended in this patient population during RT and follow-up.

Five-year survival outcomes from the PIT-1 trial: Pemetrexed-cisplatin plus bevacizumab or concurrent thoracic radiation therapy followed by surgery in stage IIIA (N2) nonsquamous non-small cell lung cancer.

8064 Background: Personized Induction Therapy-1 (PIT-1) is a multicenter, randomized phase II selection design trial of pemetrexed-cisplatin plus bevacizumab (BEV arm) or concurrent thoracic radiation therapy (TRT arm) followed by surgery in patients with stage IIIA (N2) nonsquamous non-small cell lung cancer (NSCLC). The TRT arm was chosen as the investigational induction treatment strategy for a future phase III study based on the results of a numerically higher 2-year progression-free survival (PFS, primary endpoint) in the TRT arm and fatal postoperative complications observed only in the BEV arm. We report updated, exploratory analyses of survival, approximately 5 years after the last patient was randomly assigned. Methods: Patients with stage IIIA (N2) nonsquamous NSCLC were randomly assigned (1:1) induction therapy consisting of pemetrexed and cisplatin plus bevacizumab (n = 44) or concurrent TRT (n = 44) followed by surgery. Among them, 38 patients in the BEV arm and 37 patients in the TRT arm underwent surgery. Five-year overall survival (OS), 5-year PFS, and patterns of postoperative recurrence were compared between arms. Prognostic factors of OS were analyzed in surgically resected patients using Cox’s proportional hazard model. Results: The median follow-up was 66.4 months. In 82 treated patients, the 5-year OS and PFS rates were 63.5% (95% CI: 46.9-76.1) and 26.2% (95% CI: 14.1-40.0) in the BEV arm (n = 42), and 57.2% (95% CI: 40.5-70.8) and 27.5% (95% CI: 14.9-41.7) in the TRT arm (n = 40), respectively. There were no statistical differences in OS ( P = 0.572) and PFS ( P = 0.356). In 75 surgically resected patients, pathological nodal down stage was the only significant prognostic factor of OS ( P = 0.014). Age, sex, smoking status, clinical T stage, clinical N stage based on a computed tomography scan, preoperative serum CEA and CYFRA level, EGFR mutation status, pathological complete response, and major pathological response did not have a significant prognostic impact on OS. The patterns of postoperative recurrence were different between arms: locoregional only, in four (11%) and one (3%); distant metastasis only, in 16 (42%) and 21 (57%); and both, in five (13%) and four (11%) in the BEV and TRT arms, respectively. The recurrence rate of ipsilateral hilar or mediastinal lymph nodes (the irradiation field) was significantly lower in the TRT arm (3%) than in the BEV arm (21%, P= 0.01). Conclusions: Five-year survival outcomes were not different between the BEV and TRT arms. The TRT arm demonstrated sufficient local control, but insufficient control of distant metastasis so this is an important issue that requires improvement in the future. Clinical trial information: s031180402.