Scoop: Multicenter phase I/II trial of BBI608 and pembrolizumab in patients with metastatic colorectal cancer (EPOC1503).

2020 ◽  
Vol 38 (4_suppl) ◽  
pp. 107-107 ◽  
Author(s):  
Hiroki Hara ◽  
Akihito Kawazoe ◽  
Yasutoshi Kuboki ◽  
Yoshito Komatsu ◽  
Tomohiro Nishina ◽  
...  

107 Background: The anti–PD-1 antibody pembrolizumab (P) provides response rates of 28-57% in patients (pts) with MSI-H metastatic colorectal cancer (mCRC) vs 0% in those with non-MSI-H cancers. STAT3 has been previously reported as a potential key driver of immune evasion. This study investigates efficacy and safety for the combination of BBI608 (napabucasin), which blocks phosphorylated STAT3 and downregulates IDO1 and PD-L1, with P, in pts with mCRC. BBI608 480 mg BID with P was determined as the recommended phase II dose in phase I. Methods: Phase II included Cohorts A (MSI-H) and B (non-MSI-H). Pts with mCRC not responding to or intolerant of standard chemotherapies were enrolled. The primary endpoint was immune-related objective response rate (irORR), according to irRECIST. The sample size for Cohort A (10 pts) was derived in an exploratory manner. In Cohort B, assuming null and alternative hypotheses of irORR = 5% and 20% led to an estimated required sample size of 40 pts, with a 1-sided alpha of 5% and power of 90%. Genomic profiles and the consensus molecular subtypes (CMS) of colorectal cancer were determined by whole exome sequencing and RNA sequencing as previously described. Results: From Feb/2017 to Jun/2018, 10 pts were enrolled in Cohort A and 40 in Cohort B. The irORR was 50% (5 of 10 pts) in Cohort A and 10% (95% CI 2.8 to 23.7) (4 of 40 pts) in Cohort B. Of evaluable 19 pts for CMS classification in Cohort B, CMS1, CMS2, CMS3, and CMS4 were detected in 3, 6, 4, and 6 cases, respectively. The irORR was 33% (1 of 3 pts), 0% (0 of 6 pts), 25% (1 of 4 pts), 33% (2 of 6 pts) in CMS1, CMS2, CMS3, and CMS4, respectively. One CMS3 patient with partial response had POLE mutation, while 1 CMS1 and 2 CMS4 pts with partial response did not. The most common grade 3 or higher treatment-related adverse events included fever (10%) in Cohort A, and diarrhea (5%) and appetite loss (7.5%) in Cohort B, without unexpected safety signals. No treatment-related deaths occurred. Conclusions: BBI608 with P showed encouraging anti-tumor activity with acceptable toxicity for non-MSI-H mCRC pts as well as MSI-H mCRC pts. Impact of CMS on the efficacies of this combination warrants further investigation in the additional cohort of this study. Clinical trial information: NCT02851004.

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 4093-4093 ◽  
Author(s):  
T. Yoshino ◽  
W. Koizumi ◽  
K. Yamaguchi ◽  
Y. Miyata ◽  
T. Kato ◽  
...  

4093 Background: The results of phase I portion of the treatment with the oral S-1 (a new oral fluoropyrimidine) plus oral leucovorin (LV) in patients (pts) with untreated metastatic colorectal cancer (mCRC) was reported at ESMO 2006. Dose limiting toxicities (DLTs) were grade 3 stomatitis/pharyngitis, nausea, diarrhea, ileus and exanthema. The recommended doses (RDs) for this phase II portion were determined to be S-1 40 mg/m2 and LV 25 mg/body orally given twice daily on days 1 to 14 of a 28-day cycle. The PK profiles of S-1 plus LV were similar to those of S-1 monotherapy and UFT plus LV, respectively. The main purpose of this phase II portion is to evaluate the efficacy and safety of S-1 plus LV at RD level in pts with untreated mCRC. Methods: Pts were eligible as follows; unresectable mCRC with no prior chemotherapy or receiving adjuvant chemotherapy completed at least 6 months before, histologically proven adenocarcinoma, PS(ECOG) 0–2, age 20 to 75, measurable lesions, adequate organ function and written informed consent. The pts received 40 mg/m2 of S-1 plus 25 mg/body of LV twice daily as RD in this phase II portion. The primary endpoint was the objective response rates (RRs), and secondary endpoints were time to progression (TTP) and toxicities. Results: Between Sep 2004 and Jun 2006, 56 pts of 65 enrolled pts received the treatment at RD level. The objective RRs were 55% (36 of 65) for all pts and 55% (31 of 56) for pts at RD. Disease control rates (DCRs) were 86% (56 of 65) for all pts and 86% (48 of 56) for pts at RD. Median TTP was 5.5 months for pts at RD, with a median follow-up of 5.5 months. The median survival time is under observation. During the 6 months from starting the treatment, the most common grade 3/4 toxicities at RD were as follows: diarrhea, 23%; stomatitis, 20%; anorexia, 18%; and neutropenia 13%. Conclusions: A combination of S-1 plus oral LV is an effective, well tolerated, and convenient regimen in pts with untreated mCRC, without the addition of either oxaliplatin or irinotecan. The updated results of the objective RRs, DCRs, TTP reviewed extramurally, and detailed safety profile will be presented at the meeting. This trial was supported by Taiho pharmaceutical co., Ltd., Tokyo, Japan. No significant financial relationships to disclose.


2018 ◽  
Vol 36 (4_suppl) ◽  
pp. 760-760
Author(s):  
Akihito Kawazoe ◽  
Yasutoshi Kuboki ◽  
Yoshito Komatsu ◽  
Tomohiro Nishina ◽  
Eiji Shinozaki ◽  
...  

760 Background: The anti–programmed death 1 (PD-1) antibody, pembrolizumab provided an objective response rate (ORR) of 40% in patients (pts) with Mismatch Repair–Deficient (dMMR) or Microsatellite Instability–High (MSI-H) metastatic colorectal cancer (mCRC) vs 0% in pts with MMR-proficient/Microsatellite Stable (MSS) mCRC. The WNT/β-catenin signaling has been reported to prevent anti-tumor immunity and promote resistance of anti-PD-1/PD-L1 antibodies. This study investigates efficacy and safety of the combination of BBI608, which blocks phosphorylated STAT3 and downregulates WNT/β-catenin signaling, with pembrolizumab in pts with mCRC (both MSS and MSI-H). Here, we present the results of the phase I part. Methods: Phase I part was designed to determine the recommended phase II dose (RP2D) in a “3+3” cohort-based dose escalation design of BBI608 (240mg BID every day on level 1 and 480mg BID every day on level 2) with pembrolizumab (200mg/body q3w). We also conduct biomarker research using paired samples from repeated tumor biopsies and blood collections. Results: Five pts were enrolled in level 1, and 3 pts in level 2. All pts were MSS mCRC. Seven pts were included in the safety analyses. Two pts in level 1 were excluded from dose-limiting toxicity (DLT) evaluation because of disease progression during DLT evaluation period. No DLTs were observed at either level. Grade 3 or worse treatment-related adverse events (TRAEs) were not observed. Grade 1 or 2 TRAEs included diarrhea related to BBI608 (57%), hyperthyroidism (14%), hypothyroidism (14%), and fever (14%) without unexpected safety signals. One patient in level 2 showed a tumor shrinkage lasting more than 12 weeks for lung and lymph node metastases with remarkable decline of CEA level. Analysis of repeated tumor samples from this case demonstrated that CD8+ T-cells infiltration inside the tumor on treatment was observed by immunohistochemistry and flow-cytometry. Conclusions: BBI608 480mg BID with pembrolizumab was tolerable and determined as RP2D. This combination showed a hint of activity and might evoke immunity in MSS mCRC, which will be confirmed by ongoing phase II part. Clinical trial information: NCT02851004..


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. TPS3623-TPS3623 ◽  
Author(s):  
Yasutoshi Kuboki ◽  
Akihito Kawazoe ◽  
Yoshito Komatsu ◽  
Tomohiro Nishina ◽  
Eiji Shinozaki ◽  
...  

TPS3623 Background: Immune checkpoint inhibitor (ICI) was reported to show durable responses in patients with MSI-H (Microsatellite Instability-High) metastatic colorectal cancer (mCRC). On the other hand, for patients with MSS (Microsatellite Stable) mCRC, ICI monotherapy achieved no response. Recently, WNT/β-catenin signaling has been reported to be involved in the elimination of tumor-infiltrating lymphocytes and the resistance of anti-PD-L1 antibodies. CRC is representative cancer with WNT/β-catenin pathway activation. Furthermore, STAT3 has also been reported to be a key driver of this immune evasion. Considering these rationales, the blocking of these signaling pathways with ICI may enhance antitumor immune response. Therefore, we initiated phase I/II study to assess efficacy and safety for the combination of BBI608, which blocks STAT3 and WNT/β-catenin signaling, with pembrolizumab in patients with mCRC. Methods: The eligibility criteria were patients with gastrointestinal cancer not responded to or intolerant of standard chemotherapies (SOC) for phase I part, and MSS mCRC refractory or intolerant to fluoropyrimidine, irinotecan, oxaliplatin, and anti-EGFR antibody (if wild-type RAS) for Cohort B in phase II part. For Cohort A, MSI-H mCRC refractory or intolerant to the SOC, irrespective of anti-EGFR antibody are investigated. Phase I part was designed to determine the recommended phase II dose in a “3+3” cohort-based dose escalation design of BBI608 (240mg BID every day on level 1 and 480mg BID every day on level 2) with pembrolizumab (200mg/body q3w). Primary endpoint of the phase II part is Immune-related objective response rate (irORR) determined by their Response Evaluation Criteria In Solid Tumors (irRECIST). A null hypothesis and alternative hypothesis for cohort B are irORR = 5% and 20%, respectively. Required sample size for Cohort B was 40 with a one-sided alpha of 5% and power of 90%. Required sample size for Cohort A (10 patients) was determined in an exploratory manner. We also investigate biomarker study using paired samples of both tumor biopsy and blood. The enrollment to phase I part began in November 2016. Clinical trial information: NCT02851004. Clinical trial information: NCT02851004.


2012 ◽  
Vol 30 (4_suppl) ◽  
pp. 643-643
Author(s):  
Mitsukuni Suenaga ◽  
Satoshi Matsusaka ◽  
Eiji Shinozaki ◽  
Nobuyuki Mizunuma ◽  
Kiyohiko Hatake ◽  
...  

643 Background: Capecitabine is an oral fluoropyrimidine prodrug, which is converted to fluorouracil (5-FU) predominantly in the tumor cells. In Japan, capecitabine is mainly used in combination with oxaliplatin (XELOX) in treatment for metastatic colorectal cancer (mCRC) since its approval in 2009. The results of capecitabine plus Irinotecan (CPT) (XELIRI) with or without bevacizumab (BV) in EU or US patients were previously reported, but not in Japanese. Thus, we conducted this study to assess the safety and efficacy of XELIRI plus BV in Japanese patients with mCRC. Methods: Patients with prior chemotherapy including oxaliplatin and BV for mCRC, wild or hetero type of UGT1A1 *6*28 were eligible for this study. This was a phase I study composed of two steps, and dose limiting toxicity (DLT) was assessed during the first treatment cycle. Treatment comprised capecitabine 1,000 mg/m2 twice daily from the evening of day 1 to the morning of day 8, intravenous CPT 180 mg/m2 on day 1, and BV 5mg/kg on day 1 every two weeks. To evaluate the initial safety, 3-6 patients received XELIRI+BV (CPT 150mg/m2) in step 1, and 6 patients received XELIRI+BV (CPT 180mg/m2) in step 2. If DLT occurred in 1 patient in step1, 3 patients would be newly added to step 1, and if in none of 3 or 1-2 of 6 patients, the step 2 would be started. If DLT occurred in less than or equal to 2 of 6 patients in step 2, phase II study would be proceeded, and if In more than 2 of 6 patients, phase II would be conducted at the recommended dose of step 1. Results: In step 1 and 2 of phase I, initial safety of 9 patients was confirmed without occurrence of DLT. Adverse events observed in step 1 and 2 were: neutropenia in 2 and 1; anorexia in 1 and 1; diarrhea in 1 and 1; stomatitis in 1 and 1; alanine or aspartate aminotransferase increased in 1 and 3, respectively. There was no grade 3 or greater adverse events. Conclusions: In mCRC patients with wild or hetero of UGT1A1*6*28 genotype, safety of biweekly XELIRI+BV was confirmed and recommended dose of CPT-11 was determined as 180mg/m2. Interim analysis of safety of phase II part will be reported at the meeting.


2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 4082-4082
Author(s):  
J. Maroun ◽  
D. Jonker ◽  
C. Cripps ◽  
R. Goel ◽  
T. Asmis ◽  
...  

4082 Background: This study was designed to determine the dose-limiting toxicity (DLT), maximum tolerated dose (MTD) and efficacy of the IXO regimen when used as first-line treatment for metastatic colorectal cancer (mCRC). Methods: Patients with ECOG PS 0–2, histologically proven, chemo-naïve, non-resectable mCRC were eligible. Phase I starting doses were as follows: I (180 mg/m2 i.v.) d1, X (850 mg/m2 bid orally) d2–15, O (85 mg/m2 i.v.) d1; q3w. Dose escalation (3+3 design) was based on toxicity observed at previous dose levels (DL) until DLT and the MTD were reached. Results: 39 pts (31 male/8 female, median age 58 years, ECOG PS 0–1 in 37, 95%) received a median of 11 cycles (range 1–34) at 8 DLs. 39 pts were evaluable for toxicity. The most common grade 3/4 hematological adverse events (AEs) were granulocytopenia (60%) and fever/febrile neutropenia (18%). The most common grade 3 non-hematological AEs were diarrhea (15%), vomiting (10%), fatigue (8%). No grade 3/4 neuropathy was reported. DLTs: 1 DLT was observed at each of the first 4 DLs, no DLTs at DL5 & 6, 1 at DL7 and 2 at DL8. MTD was reached at DL8. The recommended phase II dose (DL7) is as follows: I (160 mg/m2), X (950 mg/m2), O (100 mg/m2). Efficacy: 38 pts are evaluable for efficacy. The RR is 74% (95% CI 60–89), including 4 CRs, 25 PRs and 6 SDs. The disease control rate is 90% (95% CI 80–100). 10 (26%) pts had subsequent liver surgery with curative intent; 1 had lung resection. Median progression-free survival was 12.3 months (95% CI, 8–17). Overall median survival was 26.4 months (95% CI, 13–36). Conclusions: Diarrhea is the main DLT. Severe neutropenia was of short duration and manageable. The IXO regimen is well tolerated and highly effective as first-line treatment for mCRC. It appears to be particularly effective in downsizing of initially unresectable colorectal cancer liver metastases. A phase II study to confirm the efficacy/safety of IXO in combination with bevacizumab (Avastin) is ongoing. Supported by: Hoffmann La-Roche, Sanofi-Aventis, Pfizer Canada. [Table: see text]


2000 ◽  
Vol 18 (3) ◽  
pp. 659-659 ◽  
Author(s):  
Chris H. Takimoto ◽  
Geraldine Morrison ◽  
Nancy Harold ◽  
Mary Quinn ◽  
Brian P. Monahan ◽  
...  

PURPOSE: We conducted a phase I and pharmacologic study of a weekly 96-hour infusion of irinotecan to determine the maximum-tolerated dose, define the toxicity profile, and characterize the clinical pharmacology of irinotecan and its metabolites. PATIENTS AND METHODS: In 26 adult patients with solid tumors, the duration and dose rate of infusion were escalated in new patients until toxicity was observed. RESULTS: In 11 patients who were treated with irinotecan at 12.5 mg/m2/d for 4 days weekly for 2 of 3 weeks, dose-limiting grade 3 diarrhea occurred in three patients and grade 3 thrombocytopenia occurred in two patients. The recommended phase II dose is 10 mg/m2/d for 4 days given weekly for 2 of 3 weeks. At this dose, the steady-state plasma concentration (Css) of total SN-38 (the active metabolite of irinotecan) was 6.42 ± 1.10 nmol/L, and the Css of total irinotecan was 28.60 ± 17.78 nmol/L. No patient experienced grade 3 or 4 neutropenia during any cycle. All other toxicities were mild to moderate. The systemic exposure to SN-38 relative to irinotecan was greater than anticipated, with a molar ratio of the area under the concentration curve (AUC) of SN-38 to irinotecan of 0.24 ± 0.08. One objective response lasting 12 months in duration was observed in a patient with metastatic colon cancer. CONCLUSION: The recommended phase II dose of irinotecan of 10 mg/m2/d for 4 days weekly for 2 of 3 weeks was extremely well tolerated. Further efficacy testing of this pharmacologic strategy of administering intermittent low doses of irinotecan is warranted.


Cancers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 5472
Author(s):  
Hélène Bellio ◽  
Aurélie Bertaut ◽  
Alice Hervieu ◽  
Sylvie Zanetta ◽  
Audrey Hennequin ◽  
...  

The care of metastatic colorectal cancers is based on combination chemotherapies including 5-fluorouracil, oxaliplatin, irinotecan, and monoclonal antibodies targeting the epidermal growth factor receptor or vascular endothelial growth factor. The regimen is determined based on the patient’s molecular biology and general condition. Irinotecan bifractionation showed efficacy in chemorefractory patients in a previous study, FOLFIRI-3, but a desynchronized triplet has never been tested. The aim of bFOLFIRINOX-3 is to determine the safety, tolerance, and efficacy of a new regimen (FOLFIRINOX-3 bevacizumab) in chemorefractory patients. The aim of this study was to evaluate the safety and efficacy of FOLFIRINOX-3 bevacizumab in chemorefractory metastatic colorectal cancer (mCRC). A standard phase I, “3 + 3” design study was performed. The standard protocol comprised simplified FOLFOX 4 (folinic acid 400 mg/m2), 5-fluorouracil (a 400 mg/m2 bolus followed by 2400 mg/m2 for 46 h), oxaliplatin (85 mg/m2) and irinotecan (administered before and after 5-fluorouracil infusion), plus bevacizumab (5 mg/kg). In a “3 + 3” design, three different doses of irinotecan were tested: 60, 70 and 90 mg/m2. The primary endpoint was the maximum tolerable dose (MTD) of irinotecan. The secondary endpoints included the objective response (at 8 and 16 weeks) according to the RECIST 1.1 criteria and progression free survival. Thirteen patients were enrolled, and twelve patients were finally evaluated for dose-limiting toxicity (DLT). The dose level defined was 70 mg/m2 irinotecan. A total of three DLTs were observed (grade 3 diarrhea): two DLTs at the 90 mg/m2 dose level and one at the 70 mg/m2 dose level. The most frequently described adverse events were asthenia (93%), diarrhea (77%), nausea (62%) and peripheral sensory neuropathy (46%). The most frequent biological event was thrombopenia (54%). Regarding efficacy, among the 11 evaluable patients, no progression was observed at 8 weeks, and the partial response rate was 18.2%. At 16 weeks, a partial response rate of 27.3% was observed, and five patients had a stable disease. The new regimen of bFOLFIRINOX-3 with irinotecan at 70 mg/m2 was well tolerated. In chemorefractory patients, this protocol shows a high response rate.


2021 ◽  
Vol 39 (3_suppl) ◽  
pp. 57-57
Author(s):  
Hideaki Bando ◽  
Daisuke Kotani ◽  
Masahito Kotaka ◽  
Akihito Kawazoe ◽  
Toshiki Masuishi ◽  
...  

57 Background: FOLFOXIRI plus bevacizumab (BEV) is regarded as the standard of care for selected patients (pts) with metastatic colorectal cancer (mCRC), despite the high incidence of neutropenia and diarrhea. The AXEPT phase III study showed that the modified capecitabine (CAP) + irinotecan (IRI) + BEV (CAPIRI+BEV) [CAP 1600 mg/m2, IRI 200 mg/m2, and BEV 7.5 mg/kg q3wk] treatment was non-inferior to FOLFIRI+BEV, with a lower incidence of hematologic toxicity. We hypothesized that the modified CAPIRI combined with oxaliplatin (OX) and BEV (CAPOXIRI+BEV) would be more feasible than FOLFOXIRI+BEV, without compromising efficacy. Methods: The QUATTRO-II study is an open-label, multicenter, randomized phase II study. In Step 1, the recommended doses (RD) of OX and IRI were investigated as a safety lead-in. In Step 2, pts are randomized to either the RD of CAPOXIRI+BEV or FOLFOXIRI+BEV. In Step 1, four dose levels of CAPOXIRI (fixed dose of CAP 1600 mg/m2 and BEV 7.5 mg/kg plus escalated or de-escalated doses of OX and IRI, q3wk) were investigated in a 3+3 manner. A dose level of ≤ 2/6 of dose-limiting toxicity (DLT) cases was expected as the RD. Results: A total of 9 pts (3 at Level 0, 6 at Level 1) were included in Step 1. The baseline characteristics were as follows: the median age was 62 years; 6 were male; 6 presented with a left-sided tumor; 8 had a performance status of 0; all wild type/ RAS mutant/ BRAF V600E mutant were 8/1/0; and UGT1A1 wild type/*6 single hetero/*28 single hetero were 7/0/2. In Level 0 (IRI 200 mg/m2, OX 100 mg/m2), one grade 4 neutropenia and one grade 3 anorexia were observed, but without DLT. In Level 1 (IRI 200 mg/m2, OX 130 mg/m2), two grade 4 neutropenia and one grade 3 colitis were observed, with 1 DLT (febrile neutropenia) case, fully recovered without G-CSF administration. No treatment-related deaths were observed. Although dose modifications were needed in 4 of the 6 pts, no further safety concerns related to treatment continuity were observed in the 2nd or subsequent cycles. Thus, we determined that the dose administered in Level 1 is the RD for Step 2. According to the preliminary efficacy results at 8 weeks after initiating study treatment, 6 pts achieved a partial response (2 in Level 0 and 4 in Level 1). Conclusions: The RD of CAPOXIRI+BEV was 200 mg/m2 IRI, 130 mg/m2 OX, 1600 mg/m2 CAP, and 7.5mg/kg BEV. The randomized phase II Step (Step 2) of QUATTRO-II is ongoing. Clinical trial information: NCT04097444.


2000 ◽  
Vol 18 (1) ◽  
pp. 136-136 ◽  
Author(s):  
S. Giacchetti ◽  
B. Perpoint ◽  
R. Zidani ◽  
N. Le Bail ◽  
R. Faggiuolo ◽  
...  

PURPOSE: To study how adding oxaliplatin (l-OHP) to chronomodulated fluorouracil (5-FU)–leucovorin (LV) affected the objective response rate, as first-line treatment of metastatic colorectal cancer. PATIENTS AND METHODS: Two hundred patients from 15 institutions in four countries were randomly assigned to receive a 5-day course of chronomodulated 5-FU and LV (700 and 300 mg/m2/d, respectively; peak delivery rate at 0400 hours) with or without l-OHP on the first day of each course (125 mg/m2, as a 6-hour infusion). Each course was repeated every 21 days. Response was assessed by extramural review of computed tomography scans. RESULTS: Grade 3 to 4 toxicity from 5-FU–LV occurred in ≤ 5% of the patients (≤ 1% of the courses). Grade 3 to 4 diarrhea occurred in 43% of the patients given l-OHP (10% of the courses), and less than 2% of the patients had severe hematotoxicity. Thirteen percent of the patients had moderate functional impairment from peripheral sensory neuropathy. Sixteen percent of the patients receiving 5-FU–LV had an objective response (95% confidence interval [CI], 9% to 24%), compared with 53% of those receiving additional l-OHP (95% CI, 42% to 63%) (P < .001). The median progression-free survival time was 6.1 months with 5-FU–LV (range, 4.1 to 7.4 months) and 8.7 months (7.4 to 9.2 months) with l-OHP and 5-FU–LV (P = .048). Median survival times were 19.9 and 19.4 months, respectively. CONCLUSION: By chronomodulating 5-FU–LV, we were able to add l-OHP without compromising dose-intensities. l-OHP significantly improved the antitumor efficacy of this regimen.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 3506-3506
Author(s):  
Andrea Sartore-Bianchi ◽  
Filippo Pietrantonio ◽  
Sara Lonardi ◽  
Benedetta Mussolin ◽  
Francesco Rua ◽  
...  

3506 Background: Despite advances in molecular segmentation of metastatic colorectal cancer (mCRC), beyond RAS status therapeutic actionability remains confined to the limited subgroups of ERBB2 amplified, BRAF mutated and MSI-H patients. Optimization of available treatments is therefore warranted. Rechallenge with anti-EGFR monoclonal antibodies is often empirically used with some benefit as late-line therapy. We previously found that mutant RAS and EGFR ectodomain clones, which emerge in blood during EGFR blockade, decline upon antibody withdrawal leading to regain drug sensitivity. Based on this rationale, we designed CHRONOS, a multicenter phase II trial of anti-EGFR therapy rechallenge guided by monitoring of the mutational status of RAS, BRAF and EGFR in circulating tumor DNA (ctDNA). To our knowledge, this is the first interventional clinical trial of liquid biopsy for driving anti-EGFR rechallenge therapy in mCRC. Methods: Eligible patients were PS ECOG 0-2 RAS/BRAF WT mCRC having first achieved an objective response and then progression in any treatment line with an anti-EGFR antibody containing regimen, displaying RAS, BRAF and EGFR ectodomain WT status in ctDNA at molecular screening after progression to the last anti-EGFR-free regimen. Clonal evolution in ctDNA was analyzed by ddPCR and next generation sequencing. Panitumumab 6 mg/kg was administered IV every two weeks until progression. The primary endpoint was objective response rate (ORR) by RECIST version 1.1 with independent central review. 27 total patients and 6 responses were required to declare the study positive (power = 85%, type I error = 0.05). Results: Between Aug 19, 2019 and Nov 6, 2020 52 patients were screened by liquid biopsy and 36 (69%) were negative in ctDNA for RAS/BRAF/EGFR mutations. Of these, 27 patients were enrolled in 4 centers. Median age was 64 years (range: 42-80). PS ECOG was 0/50%, 1/46%, 2/4%. Previous anti-EGFR was administered in 1st line in 63%, 2nd in 15% and > 2nd in 22%. Median number of previous treatments was 3. The primary endpoint was met, with 8/27 partial responses (PR) observed (2 unconfirmed) (ORR = 30%, 95% CI: 12-47%). Stable disease (SD) was obtained in 11/27 (40%, 95% CI: 24-59%), lasting > 4 months in 8/11. Disease control rate (PR plus SD > 4 months) was therefore obtained in 16/27 (59%, 95% CI: 41-78%). Median progression-free survival was 16 weeks. Median duration of response was 17 weeks (1 ongoing). Maximal grade toxicity was G3, limited to dermatological and occurring in 19% of patients. ctDNA dynamics were studied in all patients. Conclusions: Liquid biopsy-driven rechallenge with anti-EGFR antibodies leads to further objective responses in one third of patients. Genotyping tumor DNA in the blood to direct therapy can be effectively incorporated in the management of advanced CRCs. Clinical trial information: 2016-002597-12.


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