Inclusion Criteria:

- Must be at least 18 years of age

- Stage II or III histologically-proven rectal adenocarcinoma. The distal border of the
tumor must be at or below the peritoneal reflection, defined as within 12 centimeters
of the anal verge by proctoscopic examination.

- ECOG Performance Status 0 or 1

- Adequate hematologic function as defined by:

- Absolute neutrophil count > 1,500 cells/µL

- Platelets >100,000/µL

- Hemoglobin> 9.0g/dL

- Adequate hepatic function as defined by:

- Total bilirubin < 1.5 x the upper limit of normal (ULN)

- AST and alanine aminotransferase (ALT) < 2.5 x ULN

- Albumin 3.0 g/dL

- Adequate renal function as defined by:

- Serum creatinine 1.5 x ULN

- Calculated creatinine clearance of 50 mL/min

- INR ≤ 1.5. Anticoagulation is allowed only with low molecular weight heparin (LMWH).
Patient receiving LMW heparin on stable therapeutic dose for more than 2 weeks or
with factor Xa level < 1.1U/mL are allowed on the trial.

- Willingness and ability to comply with scheduled visits, treatment plans, laboratory
tests, and other study procedures

- Ability to understand and willingness to sign a written informed consent document

- Female subjects of childbearing potential and males must agree to use adequate
contraception (e.g., hormonal or barrier method of birth control; abstinence) for the
duration of study treatment

- Female subjects of childbearing age must have a negative serum pregnancy test at
study entry.

Exclusion Criteria

- History of previous radiation therapy to the abdomen or pelvis

- History of previous chemotherapy for rectal cancer

- Major surgery within 4 weeks prior to first dose of ganetespib

- Poor venous access for study drug administration. The study drug must be administered
via peripheral venous access or through vascular access devices (VADs) (such as ports
and peripherally-inserted central catheters [PICCS] containing silicone catheters.
Use of VADs with catheters made of any other material is not allowed.

- History of severe allergic or hypersensitivity reactions to excipients (e.g.,
Polyethylene glycol [PEG] 300 and Polysorbate 80)

- Baseline QTc > 450 msec or previous history of QT prolongation while taking other
medications

- Ventricular ejection fraction (Ef)> 55% at baseline

- Treatment with chronic immunosuppressants (e.g., cyclosporine following
transplantation)

- Women who are pregnant or lactating

- Uncontrolled intercurrent illness

- Other medications, or severe acute/chronic medical or psychiatric condition, or
laboratory abnormality that may increase the risk associated with study participation
or study drug administration, or may interfere with the interpretation of study
results, and in the judgment of the investigator would make the subject inappropriate
for entry into this study

- Patients must be able to take oral medications.

- Unequivocal metastatic disease on computed tomography or chest X-ray

- Clinically significant comorbid conditions such as cardiovascular disease or
significant peripheral vascular (e.g., uncontrolled hypertension, myocardial
infarction, unstable angina) within 6 months of study entry, serious cardiac
arrhythmia requiring medication, and uncontrolled infection.

- Clinical evidence of bleeding diathesis or coagulopathy

- Significant involvement of the bladder by the tumor

- Patients with prior malignancies, including pelvic cancer, are eligible if they have
been disease free for > 5 years. Patients with prior in situ carcinomas are eligible
provided there was complete removal.