Determination of a Treatment Response Threshold for the Eosinophilic Esophagitis Endoscopic Reference Score

Background and study aims: While endoscopic features of eosinophilic esophagitis (EoE) are measured using the validated EoE Endoscopic Reference Score (EREFS), a threshold for treatment response has not been defined. We aimed to determine a cut-point for endoscopic response as measured by EREFS. Patients and Methods: We performed a secondary analysis of a randomized clinical trial comparing budesonide slurry to swallowed fluticasone multidose inhaler for initial treatment of EoE. In the parent trial, EREFS was determined before and after treatment (score range 0-9), as were histologic findings and dysphagia symptoms. We performed tabular, flexible trend, and dependent mixture analyses of measures of treatment response to select the best clinical EREFS threshold. Results: In the 111 included subjects (mean age 39 years; 67% male; 96% white), an EREFS threshold of ≤2 was 80% sensitive (95% confidence limits 69 - 88%) and 83% specific (95% confidence limits 67 - 94%) for histologic response (peak of <15 eosinophils per high-power field). Flexible trend analysis and dependent mixture modeling similarly suggested a threshold of ≤2 best captured the correlation of EREFS with histologic and symptomatic measures. Dependent mixture modeling found near total membership in the response class at EREFS of 0 or 1 and >75% at EREFS of 2 or 3. Conclusions: An EREFS of ≤2 was the best clinical threshold for endoscopic response to topical steroid treatment and was consistent with clinical and histologic response. Therefore, future studies can report a binary outcome of endoscopic response when EREFS is two or less.

Implementing a Machine Learning Strategy to Predict Pathologic Response in Patients With Soft Tissue Sarcomas Treated With Neoadjuvant Chemotherapy

PURPOSE Neoadjuvant chemotherapy (NAC) has been increasingly used in patients with locally advanced high-risk soft tissue sarcomas in the past decade, but definition and prognostic impact of a good histologic response (GHR) are lacking. Our aim was to investigate which histologic feature from the post-NAC surgical specimen independently correlated with metastatic relapse-free survival (MFS) in combination with clinical, radiologic, and pathologic features using a machine learning approach. METHODS This retrospective study included 175 consecutive patients (median age: 59 years, 75 women) with resectable disease, treated with anthracycline-based NAC between 1989 and 2015 in our sarcoma reference center, and with quantitative histopathologic analysis of the surgical specimen. The outcome of interest was the MFS. A multimodel, multivariate survival analysis was used to define GHR. The added prognostic value of GHR was investigated through the comparisons with the standard model (including histologic grade, size, and depth) and SARCULATOR nomogram using concordance indices (c-index) and Monte-Carlo cross-validation. RESULTS Seventy-two patients (72 of 175, 41.1%) had a metastatic relapse. Stepwise Cox regression, random survival forests, and least absolute shrinkage and selection operator–penalized Cox regression all converged toward the same definition for GHR, ie, < 5% stainable tumor cells. The five-year MFS probability was 1 (95% CI, 1 to 1) in patients with GHR versus 0.73 (95% CI, 0.65 to 0.81) in patients without GHR (log-rank P = .0122). The final prognostic model incorporating the GHR was significantly better than the standard model and SARCULATOR (average c-index in testing sets = 0.72 [95% CI, 0.61 to 0.82] v 0.57 [95% CI, 0.44 to 0.70] and 0.54 [95% CI, 0.45 to 0.64], respectively; P = .0414 and .0091). CONCLUSION Histologic response to NAC improves the prediction of MFS in patients with soft tissue sarcoma and represents a possible end point in future studies exploring innovative regimens in the neoadjuvant setting.

ABCB1/P-glycoprotein (Pgp) expression as stratification factor for treatment of patients with non-metastaticextremity high-grade osteosarcoma: A merged analysis of an Italian (ISG) and a Spanish (GEIS) sarcoma groups' multicentric prospective trials.

11527 Background: Overexpression of ABCB1/P-glycoprotein (Pgp) predicts poor outcome in retrospective osteosarcoma series.Two prospective trials with Pgp expression and post-induction histologic response as stratification factors were activated in Italy (ISG/OS-2) and Spain (GEIS-33). Methods: Patients ≤ 40 years with extremity non-metastatic high-grade osteosarcoma were eligible. Analysisi of Pgp expression from diagnostic biopsy was centralized. Preoperatively, all patients received methotrexate, adriamycin, cisplatinum (MAP). Surgery was performed at week 8. All patients received a dose of adriamycin following surgery. In case of Pgp overexpression (Pgp+), mifamurtide (2 mg/m2 twice/week for 3 months then weekly for 6 months) was added after surgery, with 4 consecutive cycles of ifosfamide 3 gr/m2/day, day 1-5 (HDIFO) in case of poor histologic response (necrosis < 90%) to MAP. Patients without overexpression of Pgp (Pgp-) received MAP postoperatively, regardless the pathological response. From March 2013, an amendment increased high dose methotrexate cumulative dose from 60 g/m2 (5 cycles) to 120 mg/m2 (10 cycles). The post-amendment regimen was adopted in the observational prospective study by GEIS. Here we present the merged analysis of ISG/OS-2 patients treated post-amendment and GEIS-33. Results: From March 2013 to April 2018, 274 patients were included. Median age was 14 years (range 4-38), male/female: 163/111; 90 were Pgp-, 164 were Pgp+, 20 not evaluable. With a median follow-up of 48 months (1.3-78.5 months), the 3-year EFS and OS were 71.9% (95%CI 66-76.9) and 88% (95%CI: 83.2-91.5) respectively, with no inferior survival for Pgp positive patients and improved survival for good responders (Table). Conclusions: In this prospective uncontrolled study with a risk-adapted strategy for non-metastatic osteosarcoma, survival is superior to that of all ISG/GEIS previous series. The 3-year EFS of 71.9% compares favorably with other reports. Pgp+ patients performed well in this study, in which mifamurtide and HDIFO were added after a poor response to MAP. Clinical trial information: NCT01459484; NCT04383288. [Table: see text]

Localized osteosarcoma analysis of very poor responders subgroup (Huvos I).

e22010 Background: Osteosarcoma is a malignant primitive bone tumor whose prognosis is not changed since 4 decades, after the introduction of neoadjuvant chemotherapy with Methotrexate, Cisplatin, Doxorubicine and Ifosfamide. Histologic response to preoperative chemotherapy is a significant prognostic factor. Huvos I (necrosis ≤ 50%) has worst prognosis . Previous studies reported a 3 years EFS of this Huvos I patients around 25% (Tsuda Y,2020). In order to evaluate if survival has changed in recent years in this unfavourable prognostic group we evaluated the outcome of osteosarcoma patients with Huvos I. Methods: from our Pathology archieves we retrieved all cases of localized osteosarcoma treated at Rizzoli with neoadjuvant chemotherapy who reported an histologic necrosis below or equal to 50% (Huvos I grade) after preoperative chemotherapy MAP (Ethical C. Approval 917/2020/Oss/IOR). Results: from 2003 to 2019 we had 70 cases of localized osteosarcoma with Huvos I necrosis after neoadjuvant chemotherapy ( MAP in 66 and MAPI in 4) evaluable. Median age 21,5 (3-70); M:F = 44:26. 10/70 had axial localization vs extremity(60), subhistotype distribution:46 osteoblastic,11 chondroblastic, 7 fibroblastic, 5 teleangectatic, one not classified. In 24 cases PgP was available(14 PgP positive). With a median follow up of 86.7 ms (IQR 41-136) 43/70 had already relapsed. The median EFS was 25 ms (95% CI 15-42) and the 3 yrs EFS was 40.6% (95% CI 29-52). The 3 yrs overall survival was 80% (95%CI 68-88) and median OS was not reached. Axial tumor site was associated with significant inferior EFS (P = .004). Conclusions: these data confirm the poor prognosis of patients with necrosis ≤50% and the need of new drugs to improve their survival in this sub-group.

A new perspective on the BO06 trial in osteosarcoma: short- and long-term prognostic value of histologic response and intensified chemotherapy

Purpose. Despite evidence of cured patients, previous osteosarcoma studies have not taken it into consideration. We aim to better understand the prognostic value of histologic response and chemotherapy intensification on cure fraction and progression-free survival (PFS) for the uncured patients. Methods. A logistic model is assumed for the effect of histologic response and intensified chemotherapy on the cure status, while a Cox regression model is estimated only for the uncured patients on PFS. The mixture cure model is used to simultaneously study these two effects. Results. Histologic response is a strong prognostic factor for the cure status (OR: 3.00 [1.75-5.17]), but it has no clear effect on PFS for the uncured patients (HR: 0.78 [0.53-1.16]). The cure fractions are 55% [46%-63%] and 29% [22%-35%] among GR and patients with poor histologic response (PR) respectively. The intensified regimen was associated with higher cure fraction among PR (OR: 1.90 [0.93-3.89]), with no evidence of effect for GR (OR: 0.78 [0.38-1.59]). Conclusions. Accounting for cured patients is valuable in distinguishing the covariate effects on cure and PFS for the uncured patients. Estimating cure chances based on these prognostic factors is relevant for counseling patients and can also affect treatment decisions.

P395 Impact of mirikizumab therapy on histologic measures of intestinal inflammation in a Phase 2 study of patients with moderately to severely active Crohn’s disease

Background Mirikizumab (miri), a p19-directed IL-23 antibody, demonstrated efficacy and was well-tolerated in a phase 2 randomized clinical trial (NCT02891226) in patients with Crohn’s disease (CD). The histologic results at Week (W)12 induction and W52 maintenance are presented here. Methods Patients were randomized 2:1:1:2 across 4 treatment arms (PBO, 200, 600, 1000mg miri) administered intravenously (IV) every four weeks (Q4W) at Weeks 0, 4, and 8. Patients who received miri and achieved ≥1 point improvement from baseline (BL) at W12 in Simple Endoscopic Score for Crohn’s Disease (SES-CD) were re-randomized 1:1 into double-blind maintenance to continue their IV dose assignment Q4W (IV/IV) or to 300mg miri SC Q4W (IV/SC); maintenance IV arms were pooled for analysis. W12 non-improvers and all induction PBO patients received 1000mg miri Q4W from W12 through W52. Biopsies from terminal ileum and 4 colonic segments (ascending, transverse, descending, rectum) were obtained during endoscopy at W0, 12 and 52 and scored blind to treatment and response status. Ileum and colon scores were reported separately. Colon scores were derived from the sum of the 4 colonic segments, and total intestine scores from the 4 colonic segments plus ileum. Endpoints were defined post-hoc but prior to performing the analyses and only included patients with active histologic disease at BL (see Table). Histologic response was defined as: a) absence of neutrophils in lamina epithelialis, and absence of epithelial damage, erosions and ulceration or b) decrease of either RHI or GHAS ≥50% from BL. Histologic remission was defined as absence of mucosal neutrophils, epithelial damage, erosions, and ulceration. Deep histologic remission was defined as histologic remission combined with absence of chronic inflammatory cell infiltration of the lamina propria. For assessment of total intestine inflammation, the criteria for response, remission or deep remission must have been met in all 5 bowel segments. Results At W12, histologic response and remission were significantly higher in all segments of the 1000mg group versus PBO (response: ileum p&lt;0.01, total intestine p&lt;0.01, colon p&lt;0.05; remission: ileum p&lt;0.05, colon p&lt;0.05, total intestine p&lt;0.01). Among the W12 improvers, both histologic response and histologic remission at W52 were similar in ileum and colon in the IV/IV group, but lower in ileum than colon in the IV/SC group. All but 2 patients with remission at W52 were in deep histologic remission. Conclusion Patients treated with miri achieved and sustained histologic response and remission over 52 weeks of treatment. Among patients with W52 histologic remission, all but 2 patients achieved deep remission.