Table 3.

Analysis of PAR levels and PD biomarkers of the DNA damage response in paired tumor biopsy specimens

Validated PAR-IAValidated nuclear γ-H2Ax-qIFAa (all cells in fields without necrosis)Exploratory nuclear γ-H2Ax-qIFAa (only fields with high content of viable tumor cells)Exploratory nuclear pNBS1-qIFAb (only fields with high content of viable tumor cells)
Day 2 tumor PAR contentDay 9 tumor PAR contentDecline in tumor PAR from days 2→9 (%)Day 2 nuclear γ-H2AxDay 9 nuclear γ-H2AxDay 2 nuclear γ-H2AxDay 9 nuclear γ-H2AxDay 2 nuclear pNBS1Day 9 nuclear pNBS1
28-hr of CPT-11 w/o ABT-88828-hr of CPT-11 4-hr after a.m. ABT-888 dose28-hr of CPT-11 w/o ABT-88828-hr of CPT-11 4-hr after a.m. ABT-888 dose28-hr of CPT-11 w/o ABT-88828-hr of CPT-11 4-hr after a.m. ABT-888 dose28-hr of CPT-11 w/o ABT-88828-hr of CPT-11 4-hr after a.m. ABT-888 dose
Patient numberDose level ABT-888 (mg)Best response(pg/μg protein)(pg/μg protein)(% NAP)(% NAP)(% NAP)(% NAP)(% NAP)(% NAP)
00210PD25.612.5−51<5.09.5<5.0<5.0BackgroundBackground
01020PD57.32.4−967.97.0<5.0<5.0BackgroundBackground
01420PD19.61.2−949.87.18.4n/a++n/a
01620PD5.72.2−60<5.0<5.0n/an/an/an/a
03440PD68.81.2−98<5.09.96.7<5.0DetectableBackground
00610SDn/an/an/a<5.0<5.0<5.0<5.0BackgroundBackground
00710SD2.30.3−87<5.0<5.0<5.0<5.0DetectableDetectable
02840SD12.80.6−95<5.0<5.0<5.0<5.0Detectable+
00920PR13.61.6−89<5.0<5.0n/an/an/an/a
01220PRn/an/an/a6.0<5.0n/an/an/an/a
01320PR33.76.1−82<5.05.7<5.0<5.0++++++
  • NOTE: Paired biopsies for evaluation of PAR levels in first-pass core specimens also yielded second-pass core specimens in some patients that were sufficient for analysis of nuclear PD biomarkers of the DNA damage response (DDR). Note that nuclear pNBS1 was the only PD biomarker of the DDR that exhibited a signal at sampling times selected for evaluating PAR levels. Samples demonstrating evidence of increased DNA damage or persistent DNA repair after combined irinotecan/veliparib compared with irinotecan alone are bolded.

  • Abbreviations: hr, hour; n/a, not assessable (insufficient cells for analysis).

  • aThe validated single-plex IFA for nuclear γ-H2AX employs ImagePro-based image analysis and reports %NAP for all viable cells in non-necrotic fields. The exploratory multi-plex IFA for nuclear γ-H2AX employs a Definiens-based image analysis algorithm that reports %NAP only in fields predominantly composed of viable tumor cells. Background %NAP values of nuclear γ-H2AX in untreated tumor specimens are <5%, so %NAP values must exceed this threshold to demonstrate an increase in DDR.

  • bThe term “background” means <1% positive nuclei in all fields, “detectable” means a few positive nuclei in only some fields, and “++” and “++++” indicate progressively higher numbers of strongly positive nuclei in every field.