Oral Rigosertib for Squamous Cell Carinoma

• Overall response rate [ Time Frame: Baseline to 9 weeks after start of rigosertib treatment and every 9 weeks thereafter, up to 2 years. ] [ Designated as safety issue: No ]
  Outcome is defined as the number of patients with Complete Response (CR) or Partial Response (PR) per revised Response Evaluation Criteria In Solid Tumors (RECIST 1.1). Complete response (CR) is defined as disappearance of all target lesions. Partial Response (PR) is defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.
  
  

• Overall survival (OS) [ Time Frame: Date of signing ICF to date of death, or date last known to be alive up to 2 years after discontinuation of rigosertib treatment. ] [ Designated as safety issue: No ]
  At the time of analysis, the outcome measure will be number of days between the date the patient is enrolled in the study and the date the patient dies or date the patient is last known to be alive, up to 2 years following discontinuation of rigosertib treatment.
  
  
• Progression free survival (PFS), [ Time Frame: 9 weeks, 18 weeks, and 27 weeks and every 9 weeks thereafter, up to 2 years after patient enrolled in the study. ] [ Designated as safety issue: No ]
  At the time of analysis, the outcome measure will be number of days between the date the patient is enrolled in the study and the date that progressive disease (PD) is documented per revised Response Evaluation Criteria In Solid Tumors (RECIST 1.1).
  
  
• Concentration of rigosertib in plasma [ Time Frame: Cycle 1 Day 1, Cycle 1 Day 14 and Cycle 2 Day 14 at 0, 0.5, 1, 1.5, 2, and 6 hours after the first dose of the day. ] [ Designated as safety issue: No ]
  The concentration (expressed as microgram rigosertib per mL plasma and/or nanogram rigosertib per mL plasma) of rigosertib in plasma will be determined by a validated high performance liquid chromatography (HPLC) method.
  
  
• Levels of Biomarkers [ Time Frame: Baseline ( study before drug administration) and Cycle 1, Day 14. ] [ Designated as safety issue: No ]
  Genetic and protein profiling will be conducted in blood (collected at Baseline before study drug administration) and in core biopsy or fine needle aspirate tumor samples (collected at Baseline before study drug administration and at Cycle 1 Day 14).
  
  
• Number of Adverse Events [ Time Frame: From signing of Informed Consent Form until 30 days after last dose of study drug. ] [ Designated as safety issue: Yes ]
  All Adverse Events reported by the patient or observed by the Investigator or study site personnel will be recorded. An adverse event is defined as any unfavorable or unintended sign, symptom, or disease that appears or worsens in a patient during the period of observation in a clinical study.
  
  

This will be a multicenter, Phase II study to evaluate the safety and efficacy of oral rigosertib in patients with relapsed or metastatic squamous cell carinoma (SCC) who previously received platinum-based chemotherapy and/or chemo-radiation therapy.

Only patients with head and neck squamous cell carinoma (HNSCC), non-small cell lung SCC, skin SCC, cervical SCC, penile SCC, anal SCC or esophageal SCC will be enrolled in the study.

Patients will be administered rigosertib capsules at a dose of 560 mg BID on days 1 to 14 of a 21-day cycle. Patients will be enrolled in 2 cohorts based on HPV test results:

• Cohort 1 will include up to 40 patients with human papillomavirus (HPV)-positive SCC, of which approximately 30 patients will have HNSCC, and approximately 10 patients with SCC of another origin (eg, cervix, anal, penile);
• Cohort 2 will include up to 40 patients with HPV-negative SCC, of which approximately 30 patients will have HNSCC, and approximately 10 patients with SCC of another origin (eg, lung, skin, esophageal).

Patients will be evaluated for progression after completing 3 cycles of therapy and every 3 cycles thereafter. Patients with stable disease (SD) or better, based on revised Response Criteria in Solid Tumors (mRECIST) 1.1, will receive repeated cycles of treatment on a 21-day cycle schedule until disease progression, development of unacceptable toxicity, or withdrawal of consent. Patients with progressive disease (PD) but who, in the opinion of the Investigator, appear to be deriving clinical benefit, may continue on study with a planned disease reassessment after one further cycle of therapy. Should the patient have SD or PR at this reassessment, s/he may continue on study, with subsequent reassessments every 3 cycles.

Following discontinuation of rigosertib treatment, patients' mortality status will be assessed every 3 months.