Phase II Open Label Non-Randomized Single Agent Study of the SMAC (Second Mitochondrial-Derived Activator of Caspases)-Mimetic Birinapant (TL32711; NSC 756502) in Relapsed Platinum Resistant or Refractory Epithelial Ovarian Cancer, Primary Peritoneal

BACKGROUND:

• Ovarian cancer is the ninth most common cancer in women (excluding skin cancer). It ranks fifth as the cause of cancer death in women. In the United States, 21,550 new cases and 14,600 deaths are estimated annually.
• Approximately 90% of primary malignant ovarian tumors are epithelial (carcinomas).
• Although over 70% of women with advanced disease respond to optimal debulking surgery followed by platinum-taxane based chemotherapy, duration of response is short and relapse is common. Subsequent responses to salvage therapy regimens tend to be brief (less than six months) due to the tumors progressive resistance to chemotherapy(1).
• A family of proteins, known as the Inhibitors of Apoptotic Proteins (or IAPs), plays a critical role in blocking the apoptotic signals at multiple points. IAPs regulate a number of pathways including classical or alternative nuclear factor-kappa B (NF-(K)B) function, and activation of apoptosis through either the extrinsic or intrinsic pathway. Baculoviral IAP repeat-containing protein 1 (cIAP1) acts as a critical switch to promote the pro-survival nuclear factor kappa-B (NF-B) pathway and prevent caspase activation.
• In normal cells that are stimulated to undergo apoptosis by either the extrinsic or intrinsic pathway, second mitochondrial-derived activation of caspares (SMAC) is released from the mitochondria, which antagonizes IAP, removes blockade to activated caspase function, and thereby enables apoptotic cell death. In tumor cells, however, apoptosis is dysregulated due to insufficient amounts of SMAC or upstream blockades to apoptotic activation.
• Classical activation of NF-(K)B is dependent on the presence of cIAP1 and cIAP2 proteins as part of the TNF receptor-associated factor 2 (TRAF2) complex. SMAC inhibits cIAP1 and cIAP2, leading to inactivation of tumor necrosis factor alpha (TNFalpha) mediated NF- B activation. SMAC inhibition of cIAP1 and cIAP2 leads to pathway up-regulation. Birinapant (TL32711) is a synthetic peptidomimetic antagonist of IAPs (a SMAC-mimetic), which mimics endogenous SMAC resulting in the rapid and irreversible initiation of apoptotic cell death. SMAC-mimetics represent a novel targeted therapeutic approach for cancer therapy. The addition of a SMAC mimetic, can inhibit NF- B activity, down-regulate cell survival pathways, and overcome blockades to the apoptotic pathway leading to increased tumor cell death.
• Our laboratory has demonstrated that serous ovarian cancers have cell-autonomous activation of NF-B signaling which was shown to correlate with poor prognosis.
• Therefore, we hypothesize that the SMAC-mimetic activity of birinapant may be selectively toxic to those ovarian cancers that display high canonical NF-(K)B activity.
• To summarize, relapsed platinum refractory or resistant ovarian cancer is a disease with limited therapeutic options and poor prognosis. Birinapant offers the opportunity to develop an effective and well tolerated therapeutic for the significant unmet need.

OBJECTIVES:

• The primary objective is to determine the efficacy as defined by Gynecologic Oncology Group (GOG) criteria2 as either objective response or progession-free survival lasting greater than 6 months, in patients with relapsed platinum refractory or resistant ovarian cancer, primary peritoneal cancer, fallopian tube cancer treated with birinapant.
• The seconday objectives include overall survival, safety and tolerability of single agent birinapant in this population.

ELIGIBILITY CRITERIA: