CHARIOT: a phase I study of berzosertib with chemoradiotherapy in oesophageal and other solid cancers using time to event continual reassessment method

BACKGROUND

Berzosertib (M6620) is a highly potent (IC50  =  19 nM) and selective, first-in-class ataxia telangiectasia-mutated and Rad3-related protein kinase (ATR) inhibitor. This trial assessed the safety, preliminary efficacy, and tolerance of berzosertib in oesophageal cancer (A1 cohort) with RT and advanced solid tumours (A2 cohort) with cisplatin and capecitabine.

METHODS

Single-arm, open-label dose-escalation (Time-to-Event Continual Reassessment Method) trial with 16 patients in A1 and 18 in A2. A1 tested six dose levels of berzosertib with RT (35 Gy over 15 fractions in 3 weeks).

RESULTS

No dose-limiting toxicities (DLTs) in A1. Eight grade 3 treatment-related AEs occurred in five patients, with rash being the most common. The highest dose (240 mg/m2) was determined as the recommended phase II dose (RP2D) for A1. Seven DLTs in two patients in A2. The RP2D of berzosertib was 140 mg/m2 once weekly. The most common grade ≥3 treatment-related AEs were neutropenia and thrombocytopenia. No treatment-related deaths were reported.

CONCLUSIONS

Berzosertib combined with RT is feasible and well tolerated in oesophageal cancer patients at high palliative doses. Berzosertib with cisplatin and capecitabine was well tolerated in advanced cancer. Further investigation is warranted in a phase 2 setting.

CLINICAL TRIALS IDENTIFIER

EU Clinical Trials Register (EudraCT) - 2015-003965-27 ClinicalTrials.gov - NCT03641547.

A Phase 1 Trial of the Safety, Tolerability, and Biological Effects of Intravenous Enadenotucirev (EnAd), a Novel Oncolytic Virus, in Combination with Chemoradiotherapy in Locally Advanced Rectal Cancer (CEDAR)

PURPOSE/OBJECTIVE(S)

Novel treatment combinations are required to increase response rates in rectal cancer. EnAd is an intravenous, tumor selective, oncolytic adenovirus with high affinity for malignant colorectal epithelial cells. Pre-clinical evidence of synergy with radiation warranted further clinical evaluation and assessment of safety in combination with chemoradiation (CRT), 25 × 2Gy and concurrent capecitabine.

MATERIALS/METHODS

EnAd was escalated using 2 dose levels of viral particles (1 × 1012, 3 × 1012), given Monday, Wednesday, Friday over 3 schedules (pre-CRT, pre & post CRT). Toxicity and efficacy were used as dual end points in escalation decisions. A 2-parameter and 3-parameter logistic Time to Event Continual Reassessment Method (TiTE-CRM) were used estimate the dose-toxicity and dose-efficacy relationship, respectively. Results are shown as probability and 95% credible interval (Cr.I). The dose limiting toxicity (DLT) window was 13 weeks. Patients who had not completed their DLT window at the time of a dose decision were included in the safety analysis but down-weighted according to their follow-up time and amount of IMP received. Efficacy was assessed at 13 weeks using MRI Tumor Regression Grade (mrTRG), where mrTRG 1-2 equals response. The trial (NCT03916510) was conducted in 4 UK centers.

RESULTS

A total of 13 patients were enrolled, 12 of whom were evaluable. Median age was 57 (range 31-84), and 10/13 were male. One patient had two G3 adverse events (AE); diarrhea, acute kidney injury. All other adverse events (AEs) were G1 or 2, with no G4/5 events. The most common AE by organ system was gastrointestinal (20.8%, G1). There were two observed DLTs on Dose schedule 3; leg swelling and acute kidney injury. Responses and toxicities increased with escalating schedules of EnAd (Table 1).

CONCLUSION

CEDAR is the first trial to successfully combine an intravenous oncolytic adenovirus with radiation, demonstrating the feasibility and acceptability of this approach, and a new paradigm in radiosensitization in rectal cancer. Within this small Phase I study, EnAd demonstrated an acceptable safety profile with evidence of a higher-than-expected rate of response by mrTRG. Translation analysis of tissue, blood and microbiome for biological correlates of radiation synergy is underway.

FUNDING

PsiOxus, CRUK (A24474).

SPONSOR

University of Oxford.

Analysis of metastases rates during follow-up after endoscopic resection of early "high-risk" esophageal adenocarcinoma

BACKGROUND AND AIMS

After endoscopic resection (ER) of early esophageal adenocarcinoma (EAC), the optimal management of patients with high-risk histologic features for lymph node metastases (ie, submucosal invasion, poor differentiation grade, or lymphovascular invasion) remains unclear. We aimed to evaluate outcomes of endoscopic follow-up after ER for high-risk EAC.

METHODS

For this retrospective cohort study, data were collected from all Dutch patients managed with endoscopic follow-up (endoscopy, EUS) after ER for high-risk EAC between 2008 and 2019. We distinguished 3 groups: intramucosal cancers with high-risk features, submucosal cancers with low-risk features, and submucosal cancers with high-risk features. The primary outcome was the annual risk for metastases during follow-up, stratified for baseline histology.

RESULTS

One hundred twenty patients met the selection criteria. Median follow-up was 29 months (interquartile range, 15-48). Metastases were observed in 5 of 25 (annual risk, 6.9%; 95% confidence interval [CI], 3.0-15) high-risk intramucosal cancers, 1 of 55 (annual risk, .7%; 95% CI, 0-4.0) low-risk submucosal cancers, and 3 of 40 (annual risk, 3.0%; 95% CI, 0-7.0) high-risk submucosal cancers.

CONCLUSIONS

Whereas the annual metastasis rate for high-risk submucosal EAC (3.0%) was somewhat lower than expected in comparison with previous reported percentages, the annual metastasis rate of 6.9% for high-risk intramucosal EAC is new and worrisome. This calls for further prospective studies and suggests that strict follow-up of this small subgroup is warranted until prospective data are available.

POS1092 SUBCHONDRAL BONE NORMALIZATION AFTER KNEE JOINT DISTRACTION TREATMENT AS MEASURED WITH CT

Background:

In addition to cartilage degeneration, knee osteoarthritis (OA) causes bone changes, including cortical bone thickening, subchondral bone density decrease, and bone shape changes as a result of widening and flattening condyles and osteophyte formation. Knee joint distraction (KJD) is a joint-preserving treatment for younger (<65 years) knee OA patients that has been shown to reverse OA cartilage degradation. On radiographs, KJD showed a decrease in subchondral bone density and an increase in osteophyte formation. However, these bone changes have never been evaluated with a 3D imaging technique.

Objectives:

To evaluate cortical bone thickness, subchondral trabecular bone density, and bone shape on CT scans before and one year after KJD treatment.

Methods:

19 KJD patients were included in an extended imaging protocol, undergoing a CT scan before and one year after treatment. Stradview v6.0 was used for semi-automatic tibia and femur segmentation from axial thin-slice (0.45mm) CT scans. Cortical bone thickness (mm) and trabecular bone density (Hounsfield units, HU) were measured with an automated algorithm. Osteophytes were excluded. Afterwards, wxRegSurf v18 was used for surface registration. Registration data was used for bone shape measurements. MATLAB R2020a and the SurfStat MATLAB package were used for data analysis and visualization. Two-tailed F-tests were used to calculate changes over time. Two separate linear regression models were used to show the influence of baseline Kellgren-Lawrence grade and sex on the changes over time. Statistical significance was calculated with statistical parametric mapping; a p-value <0.05 was considered statistically significant. Bone shape changes were explored visually using vertex by vertex displacements between baseline and follow-up. Patients were separated into two groups based on whether their most affected compartment (MAC) was medial or lateral. Only patients with axial CT scans at both time points available for analysis were included for evaluation.

Results:

3 Patients did not have complete CTs and in 1 patient the imaged femur was too short, leaving 16 patients for tibial analyses and 15 patients for femoral analyses. The MAC was predominantly the medial side (medial MAC n=14; lateral n=2). Before treatment, the MAC cortical bone was compared to the rest of the joint (Figure 1). One year after treatment, MAC cortical thickness decreased, although this decrease of up to approximately 0.25 mm was not statistically significant. The trabecular bone density was also higher before treatment in the MAC, and a decrease was seen throughout the entire joint, although statistically significant only for small areas on mostly the MAC where this decrease was up to approximately 80 HU (Figure 1). Female patients and patients with a higher Kellgren-Lawrence grade showed a somewhat larger decrease in cortical bone thickness. Trabecular density decreased less for patients with a higher Kellgren-Lawrence grade, and female patients showed a higher density decrease interiorly while male patients showed a higher decrease exteriorly. None of this was statistically significant. The central areas of both compartments showed an outward shape change, while the outer ring showed inward changes.

Conclusion:

MAC cortical bone thickness shows a partial decrease after KJD. Trabecular bone density decreased on both sides of the joint, likely as a direct result of the bicompartmental unloading. For both subchondral bone parameters, MAC values became more similar to the LAC, indicating (partial) subchondral bone normalization in the most affected parts of the joint. The bone shape changes may indicate a reversal of typical OA changes, although the inward difference that was seen on the outer edges may be a result of osteophyte-related changes that might have affected the bone segmentation. In conclusion, KJD treatment shows subchondral bone normalization in the first year after treatment, and longer follow-up might show whether these changes are a temporary result of joint unloading or indicate more prolonged bone changes.

Disclosure of Interests:

None declared.

A peptide derived from melanocytic protein gp100 and presented by HLA-B35 is recognized by autologous cytolytic T lymphocytes on melanoma cells

A panel of autologous cytolytic T lymphocyte (CTL) clones have been isolated from blood lymphocytes of a melanoma patient after in vitro stimulation with autologous tumor cells. We previously reported the molecular definition of three distinct antigens recognized by some of these CTL clones. We describe here, the identification of a fourth antigenic peptide expressed by this melanoma line and recognized by a CTL clone restricted by HLA-B*3503. The antigenic peptide, which is nine-amino acid long, has the sequence LPHSSSHWL and is derived from melanocyte differentiation antigen gp100. As HLA-B35 is one of the most frequent HLA-B alleles, being present in 20% of the Caucasian individuals, this peptide may be a good target for peptide-based immunotherapy of melanoma.

A tyrosinase peptide presented by HLA-B35 is recognized on a human melanoma by autologous cytotoxic T lymphocytes

We previously described different cytotoxic T lymphocyte (CTL) clones isolated from the blood lymphocytes of a melanoma patient after in vitro stimulation with autologous tumor cells. These CTL clones recognized at least 2 distinct antigens on the melanoma cells. Here, we show that one of them consists of a peptide derived from tyrosinase and presented by HLA-B35. The peptide is 9 amino acids long and has the sequence LPSSADVEF. It can be presented by the 2 major B35 allelic subtypes, B*3501 and B*3503. As HLA-B35 is one of the most frequent HLA-B specificities, being present in about 20% of Caucasian individuals, it may be a useful target for peptide-based immunotherapy of melanoma.