Phase 1b/2 Trial of 5-fluorouracil, Leucovorin, Irinotecan in Combination With Temozolomide (FLIRT) and Bevacizumab for the First-line Treatment of Patients With MGMT Silenced, Microsatellite Stable Metastatic Colorectal Cancer.
An upfront-intensified treatment combining all the three active cytotoxic agents in metastatic colorectal cancer (mCRC) including fluoropyrimidines, oxaliplatin, irinotecan (FOLFOXIRI) plus antiangiogenic blockade with bevacizumab significantly improved survival. No biomarkers are available for predicting sensitivity/resistance to single chemotherapeutic drugs, the simultaneous delivery of all active chemotherapeutic agents might overcome resistance to single drugs. Temozolomide has modest but non-negligible activity (about 10%) in chemo-refractory patients with MGMT methylated mCRC. The response rate to temozolomide-based therapy in pretreated patients is increased to up to 20% when restricting the focus on those with MGMT IHC-negative/MGMT methylated and MSS cancers. Clinical and preclinical synergy has been reported for combination of temozolomide with irinotecan and fluoropyrimidines. Temozolomide could be regarded as a targeted chemotherapy for patients with MSS and MGMT silenced tumors. In this subgroup of patients, an intensified triplet upfront regimen including temozolomide, fluoropyrimidines, irinotecan, associated with bevacizumab, could be a novel combination in molecularly super-selected mCRC patients. Moving from this, the investigators designed this open-label, monocentric, phase 1b study evaluating the safety of the combination regimen 5-fluorouracil, leucovorin, irinotecan, temozolomide and bevacizumab in patients with MGMT silenced and MSS mCRC. The study will consist in a dose-escalation assessment of the safety of the treatment in subjects with previously untreated MGMT silenced, MSS mCRC. A 3 + 3 design will be used to assess the maximum tolerated dose (MTD) or maximum tested dose of the combination FLIRT-bevacizumab. Upon completion of the phase 1b part, the phase 2 part of the study will start.
• Histologically confirmed metastatic adenocarcinoma of the colon and/or rectum.
• Confirmed MGMT promoter methylation by PSQ (\> 5%) and absent MGMT expression by immunohistochemistry.
• Locally assessed pMMR or MSS status.
• Written informed consent obtained prior to any study procedures.
• Availability of archival tumor tissue (primary tumor and metastases or at least one of the two) for confirmation of MGMT, MMR/MSI status and biomarker analyses.
• Availability of blood sample for biomarker analysis.
• Metastatic colorectal cancer not previously treated with chemotherapy for metastatic disease.
• At least one measurable lesion according to RECIST 1.1.
• Age ≥ 18 and less or equal than 75 years.
⁃ ECOG PS ≤ 1 if patient \< 70 years old; ECOG PS 0 if patient 70-75 years old.
⁃ Life expectancy of at least 12 weeks.
⁃ Previous (neo)adjuvant fluoropyrimidine or fluoropyrimidine plus oxaliplatin chemotherapy allowed only if more than 6 months elapsed between the end of (neo)adjuvant therapy and first evidence of disease relapse.
⁃ Neutrophils ≥1.5 x 109/L, Platelets ≥100 x 109/L, Hemoglobin ≥ 9 g/dl.
⁃ Total bilirubin ≤1.5 fold the upper-normal limits (UNL), AST (SGOT) and/or ALT (SGPT) ≤ 2.5 x UNL (or \<5 x UNL in the case of liver metastases), alkaline phosphatase ≤ 2.5 x UNL (or \<5 x UNL in case of liver metastases).
⁃ Creatinine clearance ≥ 50 mL/min or serum creatinine ≤1.5 x UNL.
⁃ Women of childbearing potential must have a negative blood pregnancy test at the baseline visit. For this trial, women of childbearing potential are defined as all women after puberty, unless they are postmenopausal for at least 12 months, are surgically sterile, or are sexually inactive. A postmenopausal state is defined as no menses for 12 months without an alternative medical cause. A high follicle stimulating hormone (FSH) level in the postmenopausal range may be used to confirm a post-menopausal state in women not using hormonal contraception or hormonal replacement therapy. However, in the absence of amenorrhea, a single FSH measurement is insufficient.
⁃ Male subjects with female partners of childbearing potential and female subjects of childbearing potential must be willing to use adequate contraception as approved be the Investigator (barrier contraceptive measure or oral contraception) as outlined in Section 7.6, starting with the screening visit and through 6 months after the last treatment dose. Note: abstinence is acceptable if this is the usual lifestyle and preferred contraception for the subject.
⁃ Will and ability to comply with the protocol.
⁃ Is willing and able to provide an adequate archival tumor sample (FFPE) available for molecular screening and exploratory analyses. If the tumor block is not available, a minimum of 25 3-micron unstained sections on charged slides of tumor will be required.