Inclusion Criteria:

          -  Written informed consent

          -  Pathologically documented adenocarcinoma or poorly differentiated locally
             advanced/metastatic colorectal cancer

          -  Have at least 1 measurable lesion per Response Evaluation Criteria in Solid Tumors
             (RECIST) version 1.1 as assessed by the Investigator

          -  Adults ≥18 years

          -  Eastern Cooperative Oncology Group performance status (ECOG PS) 0 to 1

          -  Adequate cardiac function, as defined by left ventricular ejection fraction (LVEF)
             ≥45%

          -  Adequate organ function

          -  Prothrombin time ≤1.5 x ULN or international normalized ratio within ≤1.5; and either
             partial thromboplastin time or activated partial thromboplastin time ≤1.5 x ULN.
             Patients on warfarin may be included if on a stable dose with a therapeutic INR <3.5

          -  Woman of child-bearing potential must have a negative serum or urine pregnancy test
             within 2 weeks prior to treatment

          -  Men and women of child-bearing potential agree to use acceptable contraceptive methods
             while on the study and continue to use acceptable contraceptive methods for 1 month
             after the last dose of study therapy

          -  Able to adhere to study visit schedule, protocol requirements and survival assessments
             during follow up period

          -  Patients with diabetes mellitus should be on stable regimen of oral hypoglycemic
             therapy and/or insulin before beginning study treatment and serum glucose values
             should consistently be grade 2 or less.

        Inclusion Criteria for RGX-202-01 plus FOLFIRI and bevacizumab dose escalation and
        expansion stages:

          -  Must have received only one prior standard of care oxaliplatin-containing regimen for
             locally advanced/metastatic colorectal cancer

          -  Must have received prior treatment with pembrolizumab or an FDA approved PD-1/L1
             inhibitor as well, if the patient has dMMR/MSI-H colorectal cancer

          -  May have received prior treatment with bevacizumab, cetuximab, or panitumumab, or an
             FDA approved biosimilar.

          -  Expansion stage participants should also meet the additional inclusion criterion of
             centrally determined CKB expression by an immunohistochemistry (IHC) method

        Exclusion Criteria:

          -  Unresolved Grade > 2 toxicities from prior anticancer therapy; excluding Grade 2
             chemotherapy-related neuropathy, alopecia; and excluding Grade 2-3 asymptomatic
             laboratory abnormalities if considered clinically insignificant by the Investigator,
             or can be managed with available medical therapies

          -  Has malignancy of small cell, neuroendocrine, or squamous histology

          -  Unable to meet the requirement of an adequate treatment washout period before
             enrollment

          -  Has additional malignancy that may confound the assessment of study endpoints.
             Participants with non-melanoma skin cancer, carcinoma in situ (including transitional
             cell carcinoma, cervical intraepithelial neoplasia, and melanoma in situ),
             organ-confined prostate cancer with no evidence of progressive disease are not
             excluded

          -  Has clinically significant cardiovascular disease (New York Heart Association Class
             III or IV congestive heart failure, history of myocardial infarction, uncontrolled
             angina, unstable angina or stroke within 6 months before enrollment, uncontrolled
             hypertension or clinically significant arrhythmias not controlled by medication

          -  Has clinically active brain or leptomeningeal metastases

          -  Has uncontrolled intercurrent illness including, but not limited to, uncontrolled
             infection, disseminated intravascular coagulation, or psychiatric illness/social
             situations that would limit compliance with study requirements

          -  Pregnant or breast feeding

          -  Has an ongoing chronic hepatopathy of any origin

          -  Has an evidence of muscular dystrophies or ongoing muscle pathology

          -  Has oxygen-support requirements

          -  Has corrected QT interval (QTc) prolongation to >470 ms (females) or >450 ms (males)

          -  Has a physical abnormality or medical condition that limits swallowing multiple pills
             or has a history of non-adherence to oral therapies

          -  Has a malabsorption condition, such as short bowel syndrome, impaired GI function or
             GI disease that may significantly alter absorption, or a high likelihood of impending
             bowel obstruction, such as strictures

          -  Has clinically significant ascites (i.e. requiring paracentesis within the preceding
             28 days or treatment with pain medication)

          -  Has a medical condition which, in the opinion of the Investigator, places the patient
             at an unacceptably high risk for toxicities

        Exclusion Criteria for RGX-202-01 plus FOLFIRI and bevacizumab dose escalation and
        expansion stages:

          -  Has known dihydropyrimidine dehydrogenase (DPD) deficiency or is on treatment with DPD
             inhibitors, including sorivudine or its chemically related analogues such as
             brivudine, within 4 weeks prior to the start of treatment

          -  Has known homozygous or heterozygous for UGT1A1*28, UGT1A1*6, UGT1A9*1 or ABCG2 allele

          -  Require treatment with strong CYP3A4 inhibitors or strong UGT1A1 inhibitors

          -  Previously treated with FOLFIRI or other irinotecan containing regimens

          -  Has proteinuria ≥ 2gm/24 and/or nephrotic syndrome. Patients with a proteinuria 2+ or
             greater urine dipstick reading should undergo further assessment, e.g., a 24-hour
             urine collection

          -  History of acute or subacute intestinal occlusion - except if such an event occurred
             only around the time of diagnosis - or chronic inflammatory bowel disease or chronic
             diarrhea

          -  History of severe, non-healing wounds, ulcers or bone fractures

          -  History of arterial thromboemboli or severe hemorrhage within 6 months of prior
             FOLFIRI treatment with an exception of tumor bleeding before tumor resection surgery

          -  History of hemorrhagic diathesis or tendency towards thrombosis