Trial Information

A Phase II Evaluation of Metformin, Targeting Cancer Stem Cells for the Prevention of Relapse in Patients With Stage IIC/III/IV Ovarian, Fallopian Tube, and Primary Peritoneal Cancer

Despite 70% remission rates with surgery and chemotherapy, the majority of patients with
stage III/IV ovarian cancer will relapse and die of their disease. This is consistent with a
cancer stem cell (CSC) model in which a few residual treatment resistant stem cells persist
and initiate disease recurrence. Laboratory studies indicate therapies targeting CSC will
greatly improve cancer outcomes. We have recently characterized a population of CSC in
ovarian cancer. Importantly, similar to that observed in breast cancer, we have found that
the diabetes drug metformin can restrict ovarian CSC growth and proliferation. In addition
metformin increases tumor cell sensitivity to chemotherapy. Consistent with this,
epidemiologic studies demonstrate that diabetic patients with ovarian cancer taking
metformin have better outcomes than those not taking metformin. However, metformin has not
been tested as an anti-cancer stem cell agent in ovarian cancer. Thus we propose to perform
a phase II clinical trial using metformin as an anti-cancer stem cell agent in ovarian
cancer patients. Patients who plan to receive primary surgical debulking will initiate
metformin therpay prior to surgery and then continue after surgrey along with chemotherapy.
Patients who will be treated neoadjuvantly will initiate metformin with chemtherapy prior to
sugrery and then continue both metformin and chemotherpy after surgery. Tumor specimens will
be acquired for all patients at the time of primary surgery. The primary objective of this
study will be to determine if metformin improves the recurrence-free survival (RFS) of
patients relative to historical controls. Secondary objectives of this study will be: (a) to
compare the amount of CSC in primary tumor specimens in metformin treated patients versus
matched controls from our tumor bank, (b) to determine if metformin improves overall
survival relative to historical controls, (c) to confirm the safety of metformin in
non-diabetic ovarian cancer patients, and (d) as laboratory studies indicate that metformin
is most active in p53 mutant cells and p53 is mutated in ~50% of ovarian cancers, we will
assess whether response rates correlate with p53 mutation status. If successful, this well
tolerated FDA approved drug could be immediately translated into phase III trials and impact
patient outcomes.