EZN-2208 (Pegylated SN-38) in Combination With Bevacizumab in Refractory Solid Tumors

Background

One reason postulated for the limited efficacy of anti-angiogenic or anti-VEGF agents such as
bevacizumab is that they cause intra-tumoral hypoxia, resulting in the induction and
up-regulation of hypoxia-inducible factors (HIF) such as HIF-1Alpha. These in turn play a
central role in tumor progression by acting as master regulators of how cancer cells adapt to
hypoxic conditions. HIF-1Alpha therefore represents an attractive target in oncology.

Camptothecin analogues (including SN-38, topotecan, and irinotecan) have been shown to
consistently reduce the translation, expression, and transcriptional activity of HIF-1Alpha
in vitro and in vivo, and therefore have the potential to inhibit the HIF-1? induction that
occurs with anti-angiogenic agents.

The central rationale of this study is that HIF-1alpha induction by bevacizumab will be
offset by weekly administration of EZN-2208 (PEGylated SN-38), and that this will result in
synergistic anti-tumor effects.

Objectives

Determine the modulation of HIF-1alpha protein (by ELISA) in solid tumors after treatment
with EZN-2208 and bevacizumab.

Determine the safety and tolerability of the combination of EZN-2208 and bevacizumab with
EZN-2208 administered weekly times 3 (Days 1, 8, and 15) and bevacizumab administered every 2
weeks in 28-day cycles.

Perform correlative studies to assess changes in angiogenesis in tumor tissue.

Evaluate antitumor responses as determined by RECIST.

Eligibility

Adults with histologically documented solid tumors, whose disease has progressed following
standard therapy or who have no acceptable standard treatment.

Performance status ECOG 0-2; adequate organ function; life expectancy at least 3 months; no
major surgery, radiation or chemotherapy within 4 weeks prior to study enrollment; recovered
from toxicities of prior therapies to at least eligibility levels.

Willingness to undergo tumor biopsies for research purposes.

Study Design

This is a single-arm pilot study.

Patients will receive EZN-2208 IV on Day 1, 8, and 15 of a 28-day cycle at a dose of 9
mg/m(2); bevacizumab will be administered IV every 2 weeks at a dose of 5 mg/kg.

For cycle 1: Bevacizumab will be administered on Day -7 (i.e., 1 week prior to EZN-2208) and
Day 15.

For subsequent cycles: Bevacizumab will be administered on Day 1 and 15.

- INCLUSION CRITERIA:

Patients must have histologically confirmed (by the Laboratory of Pathology, NCI) solid
tumors that are metastatic or unresectable and for which standard therapies do not exist or
are no longer effective.

There are no restrictions on prior therapy.

Age greater than or equal to18 years. Because no dosing or adverse event data are currently
available on the use of EZN-2208 in combination with bevacizumab in patients less than 18
years of age, children are excluded from this study, but will be eligible for future
pediatric Phase I combination trials.

ECOG performance status less than or equal to 2 (Karnofsky greater than or equal to 60%

Life expectancy of greater than 3 months.

Patients must have normal organ and marrow function as defined below:

leukocytes greater than or equal to 3,000/mcL

absolute neutrophil count greater than or equal to 1,500/mcL

platelets greater than or equal to 100,000/mcL

total bilirubin less than or equal to 1.5 times the institutional upper limit of normal

AST(SGOT)/ALT(SGPT) less than or equal to 2.5 times the institutional upper limit of normal

creatinine less than or equal to 1.5 times the institutional upper limit of normal

OR

creatinine clearance greater than or equal to 60 mL/min/1.73 m(2) for patients with
creatinine levels above institutional normal.

The effects of EZN-2208 on the developing human fetus are unknown. For this reason and
because bevacizumab is known to be teratogenic, women of childbearing potential and men
must agree to use adequate contraception (hormonal or barrier method of birth control;
abstinence) prior to study entry, for the duration of study participation, and for 3 months
after completion of study. Should a woman become pregnant or suspect she is pregnant while
participating in this study, she should inform her treating physician immediately.

Ability to understand and the willingness to sign a written informed consent document.

Disease amenable to biopsy, and willingness to undergo biopsies.

EXCLUSION CRITERIA:

Patients who have had chemotherapy or radiotherapy within 4 weeks (6 weeks for nitrosoureas
or mitomycin C) prior to entering the study or those who have not recovered from adverse
events due to agents administered more than 4 weeks earlier. Patients must be (Bullet) 2
weeks since receiving study drug as a participant in a Phase 0 study (also referred to as
an early Phase I study where a subtherapeutic dose of drug is administered).

Patients may not be receiving any other investigational agents.

Patients with a diagnosis of colorectal cancer, who have previously failed treatment with a
topoisomerase I inhibitor. Patients with all other types of malignancies will be considered
for eligibility regardless of prior exposure to topoisomerase 1 inhibitors.

History of allergic reactions attributed to compounds of similar chemical or biologic
composition to EZN-2208 or bevacizumab.

Uncontrolled intercurrent illness including, but not limited to, clinically significant
cardiovascular disease as defined below, or psychiatric illness/social situations that
would limit compliance with study requirements.

Pregnant women are excluded from this study because bevacizumab is an antiangiogenic agent
with the potential for teratogenic or abortifacient effects. Because there is an unknown
but potential risk for adverse events in nursing infants secondary to treatment of the
mother with EZN-2208, breastfeeding should be discontinued if the mother is treated with
EZN-2208.

HIV-positive patients on combination antiretroviral therapy are ineligible because of the
potential for pharmacokinetic interactions with EZN-2208. In addition, these patients are
at increased risk of lethal infections when treated with marrowsuppressive therapy.
Appropriate studies will be undertaken in patients receiving combination antiretroviral
therapy when indicated.

Urine protein should be screened by urine analysis. If protein is 2+ or higher, 24-hour
urine protein should be obtained and the level should be <1000 mg for patient enrollment.

Serious or non-healing wound, ulcer, or bone fracture. History of abdominal fistula,
gastrointestinal perforation, or intra-abdominal abscess within the past 6 months.

Invasive procedures defined as follows:

- Major surgical procedure, open biopsy, or significant traumatic injury within the past
28 days.

- Anticipation of need for major surgical procedures during the course of the study.

Significant vascular disease (e.g., aortic aneurysm, requiring surgical repair or recent
peripheral arterial thrombosis) within the past 6 months.

Known CNS disease except for treated brain metastasis. Treated brain metastases are defined
as having no ongoing requirement for steroids and no evidence of progression or hemorrhage
after treatment for at least 3 months, as ascertained by clinical examination and brain
imaging (MRI or CT). Patients receiving EIAED anticonvulsants will not be eligible to
participate (Appendix B). Patients on non-EIAED may be enrolled at the discretion of the
PI. Treatment for brain metastases may include whole brain radiotherapy (WBRT),
radiosurgery (RS; Gamma Knife, LINAC, or equivalent), or a combination as deemed
appropriate by the treating physician.

Patients with clinically significant cardiovascular disease are excluded:

- Inadequately controlled hypertension (systolic blood pressure >160 mm Hg and/or
diastolic blood pressure >90 mm Hg despite antihypertensive medication)

- History of stroke/cerebrovascular accident within 6 months

- Myocardial infarction or unstable angina within 6 months

- New York Heart Association grade II or greater congestive heart failure

- Serious and inadequately controlled cardiac arrhythmia

- Significant vascular disease (e.g., aortic aneurysm, history of aortic dissection)

- Clinically significant peripheral vascular disease

Evidence of bleeding diathesis or coagulopathy. Patients on therapeutic anticoagulation
will be excluded.

Patients with known hypersensitivity to Chinese hamster ovary cell products or other
recombinant human antibodies.