• The severity and incidence of thrombocytopenia as determined by the number of patient chemotherapy cycles during which the platelet count measures below 50,000/mm3 (NCI Grade 3 and/or 4 thrombocytopenia). [ Time Frame: During a maximum of six 3-week chemotherapy cycles ] [ Designated as safety issue: No ]
  

• The severity and incidence of thrombocytopenia as determined by the number of patients who experience a platelet count below 50,000/mm3 (NCI Grade 3 and/or 4 thrombocytopenia). [ Time Frame: During a maximum of six 3-week chemotherapy cycles ] [ Designated as safety issue: No ]
  
• The severity and incidence of thrombocytopenia as determined by absolute nadir and time to recovery of platelet count for each treatment cycle and study subject. [ Time Frame: During a maximum of six 3-week chemotherapy cycles ] [ Designated as safety issue: No ]
  
• The frequency and severity of Serious Adverse Events [ Time Frame: During a maximum of six 3-week chemotherapy cycles ] [ Designated as safety issue: Yes ]
  
• The incidence and grade of toxicity experienced by each dose group, changes in biochemistry, hematology, urinalysis, physical findings, and adverse events [ Time Frame: During a maximum of six 3-week chemotherapy cycles ] [ Designated as safety issue: Yes ]
  

This is a Phase IIb, multicenter, randomized, double-blind, placebo-controlled study comparing safety and efficacy of two dose levels of TXA127 when administered during 6 cycles of combination gemcitabine and platinum-based chemotherapy. This study intends to investigate the effectiveness of TXA127 for the mitigation of severity and/or incidence of thrombocytopenia, as well as safety when administered as a self-injected, subcutaneous solution.

Patients diagnosed with recurrent ovarian cancer after a progression-free interval of at least 3 months following cytoreduction surgery and a single course of chemotherapy who are scheduled to undergo second-line, combination chemotherapy with gemcitabine and carboplatin or gemcitabine and cisplatin will be considered for this study.

Subjects will be randomized in a 1:1:1 ratio to one of the following three blinded treatment groups: placebo, 100 ug/kg/day TXA127 and 300 ug/kg/day TXA127.

Treatment will be concurrent with up to six consecutive 21-day cycles of one of the following gemcitabine and platin regimens:

Regimen A

• Intravenous cisplatin therapy at a dose of 30 mg/m2 given on Days 1 and 8 of the cycle
• Intravenous gemcitabine at a dose of 750 mg/m2 given after cisplatin on Days 1 and 8 of the cycle.

Regimen B

• Intravenous gemcitabine at a dose of 1000 mg/m2 given on Days 1 and 8 of the cycle
• Intravenous carboplatin AUC 4 given after gemcitabine on Day 1 of the cycle

TXA127 will be self-administered as a subcutaneous injection by the subject once daily on Days 2-6 and 9-15 during each cycle of chemotherapy. Blood specimens will be drawn for hematologic analysis on Days 1, 8 and 15 of each treatment cycle.