Javelin BRCA/ATM: Avelumab Plus Talazoparib in Patients With BRCA or ATM Mutant Solid Tumors

An adverse event (AE) was any untoward medical occurrence in a clinical investigation where participants administered a product or medical device. TEAEs were those events with onset dates occurring during the on-treatment period. A Serious Adverse Event (SAE) was any untoward medical occurrence at any dose that: resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, or resulted in congenital anomaly/birth defect. A treatment-related AE was any untoward medical occurrence attributed to the study drug in a participant who received study drug. TEAEs were graded by the investigator using National Cancer Institute Common Toxicity Criteria for Adverse Events (NCI CTCAE) v4.03 as Grade 1 = mild; Grade 2 = moderate; Grade 3 = severe; Grade 4 = life-threatening; Grade 5 = death related to AE.

The laboratory results were graded according to the CTCAE v4.03 severity grade whenever applicable. Laboratory test abnormalities were summarized according to worst toxicity grade observed for each laboratory test. As per NCI CTCAE toxicity grading v4.03, Grade 1 = mild; Grade 2 = moderate; Grade 3 = severe; Grade 4 = life-threatening; Grade 5 = death related to AE. On-treatment period was defined as the time from the first dose of study treatment through minimum (30 days + last dose of study treatment, start day of new anti-cancer drug therapy - 1 day).

The laboratory results were graded according to the CTCAE v4.03 severity grade whenever applicable. Laboratory test abnormalities were summarized according to worst toxicity grade observed for each laboratory test. As per NCI CTCAE toxicity grading v4.03, Grade 1 = mild; Grade 2 = moderate; Grade 3 = severe; Grade 4 = life-threatening; Grade 5 = death related to AE. On-treatment period was defined as the time from the first dose of study treatment through minimum (30 days + last dose of study treatment, start day of new anti-cancer drug therapy - 1 day).

Ctrough was defined as predose concentration during multiple dosing. The determination method of Ctrough was observing directly from data. The lower limit of quantification (LLQ) was 0.2 mcg/mL. For Cycle 1 Day 1, as the number of observations above lower limit of quantification (NALQ) = 0, summary statistics were not presented.

Cmax was defined as maximum observed plasma concentration. The determination method of Cmax was observing directly from data.

Ctrough was defined as predose concentration during multiple dosing. The determination method of Ctrough was observing directly from data. The lower limit of quantification (LLQ) was 25 pg/mL. For Cycle 1 Day 1, as the number of observations above lower limit of quantification (NALQ) = 0, summary statistics were not presented. Evaluable participants were participants with non-missing Ctrough concentrations at each specific time point and meeting 2 conditions: participants received 14 consecutive days of talazoparib dose without dosing interruption prior to sample collection (except on Cycle 1 Day 1) and sample collection within 24 hours ± 10% (2 hours and 24 minutes) after the previous day's dose and no more than 5 minutes (0.083 hours) after the administration of the dose on the day of PK sample collection. Predose PK samples on Cycle 1 Day 1 must have been collected prior to dose.

In this OM, the post-dose concentrations for talazoparib in plasma were reported.

Blood samples were assayed for ADA using a validated assay. ADA never-positive = no positive ADA results at any time point. ADA ever-positive =at least one positive ADA result at any time point. Baseline ADA positive =a positive ADA result at baseline. Treatment-boosted ADA =a positive ADA result at baseline and the titer >=8×baseline titer at least once after treatment with avelumab. Treatment-induced ADA = participant was ADA-negative at baseline and had at least one positive post-baseline ADA result; or the participant had at least one positive post-baseline ADA result if no baseline sample. Transient ADA response = participants with treatment-induced ADA had (a single positive ADA result or duration between first and last positive result <16 weeks) and ADA result at the last assessment was not positive. Persistent ADA response =participants with treatment-induced ADA had duration between first and last positive ADA result >=16 weeks or a positive ADA result at the last assessment.

Nab ever-positive was defined as at least one positive Nab result at any time point. Samples positive for ADA with persistent treatment-induced ADA response could be analyzed for Nab.

For participants with solid tumors, except mCRPC, OR was defined as a CR or PR per RECIST v1.1, both confirmed by repeat assessments performed no less than 4 weeks after the criteria for response were first met. For participants with mCRPC, OR was defined as the percentage of participants with a best overall soft tissue response of CR or PR per RECIST v1.1 with no evidence of confirmed bone disease progression per PCWG3 criteria. Per RECIST v1.1, CR was defined as complete disappearance of all target and non-target lesions with the exception of nodal disease. PR was defined as greater than or equal to 30% decrease under baseline of the sum of diameters of all target measurable lesions. Non-target PR lesions must be non-PD, where PD was unequivocal progression of pre-existing lesions.

For participants with solid tumors, except mCRPC: TTR was defined for participants with confirmed objective response (CR or PR) as the time from the first dose of study treatment to the first documentation of objective tumor response. For participants with mCRPC: TTR was defined as the time from the first dose of study treatment to the first objective evidence of soft tissue response with no evidence of confirmed bone disease progression on bone scan per PCWG3. Soft tissue response was defined as a Best Overall Response (BOR) of CR or PR per RECIST v1.1.

For participants with solid tumors, except mCRPC: TTR was defined for participants with confirmed objective response (CR or PR) as the time from the first dose of study treatment to the first documentation of objective tumor response. For participants with mCRPC: TTR was defined as the time from the first dose of study treatment to the first objective evidence of soft tissue response with no evidence of confirmed bone disease progression on bone scan per PCWG3. Soft tissue response was defined as a BOR of CR or PR per RECIST v1.1.

For participants with solid tumors, except mCRPC: DoR was defined for participants with confirmed objective response (CR or PR) as the time from the first documentation of objective tumor response to the first documentation of objective tumor progression or to death due to any cause, whichever occured first. For participants with mCRPC: DoR was defined for participants with confirmed objective response (CR or PR) as the time from the first objective evidence of soft tissue response (subsequently confirmed) per RECIST v1.1 and no evidence of confirmed bone disease progression by PCWG3 to the first subsequent objective evidence of radiographic progression or death due to any cause, whichever occured first. Radiographic progression was defined as soft tissue progression evaluated per RECIST v1.1 or bone disease progression evaluated per PCWG3.

For participants with solid tumors, except mCRPC: DoR was defined for participants with confirmed objective response (CR or PR) as the time from the first documentation of objective tumor response to the first documentation of objective tumor progression or to death due to any cause, whichever occurred first. For participants with mCRPC: DoR was defined for participants with confirmed objective response (CR or PR) as the time from the first objective evidence of soft tissue response (subsequently confirmed) per RECIST v1.1 and no evidence of confirmed bone disease progression by PCWG3 to the first subsequent objective evidence of radiographic progression or death due to any cause, whichever occurred first. Radiographic progression was defined as soft tissue progression evaluated per RECIST v1.1 or bone disease progression evaluated per PCWG3.

For participants with solid tumors, except mCRPC: PFS was defined as the time from the first dose of study treatment to the date of disease progression by RECIST v1.1 or death due to any cause, whichever occurred first. For participants with mCRPC: PFS was defined as the time from the first dose of study treatment to documentation of radiographic progression in soft tissue evaluated per RECIST v1.1, in bone evaluated per PCWG3, or death, whichever occurred first.

For participants with solid tumors, except mCRPC: PFS was defined as the time from the first dose of study treatment to the date of disease progression by RECIST v1.1 or death due to any cause, whichever occurred first. For participants with mCRPC: PFS was defined as the time from the first dose of study treatment to documentation of radiographic progression in soft tissue evaluated per RECIST v1.1, in bone evaluated per PCWG3, or death, whichever occurred first.

OS was defined as the time from the first dose of study treatment to the date of death. Participants without an event (death) were censored at the date of last contact.

For participants with mCRPC, time to PSA progression was defined as the time from the first dose to the date that a >=25% increase in PSA with an absolute increase of >=2 μg/L (2 ng/mL) above the nadir (or baseline for participants with no PSA decline) was documented, confirmed by a second consecutive PSA value obtained >=3 weeks (21 days) later.

For participants with mCRPC, PSA response was defined as confirmed PSA decline >=50% compared to baseline. PSA response was calculated as a decline from baseline PSA (ng/mL) to the maximal PSA response with a threshold of 50%. A PSA response must have been confirmed by a second consecutive value at least 3 weeks later.

For participants with mCRPC, CTC count conversion was defined as a decrease in CTC count from >=5 CTC per 7.5 mL of blood at baseline to <5 CTC per 7.5 mL of blood anytime on study.

For participants with ovarian cancer, CA-125 response was defined as at least a 50% reduction in CA-125 levels from baseline. The response must have been confirmed and maintained for at least 28 days.

PD-L1 expression on tumor and infiltrating immune cells was measured by immunohistochemistry (IHC). PD-L1 expression level was defined as the number of PD-L1 positive cells and/or qualitative assessment of PD-L1 staining on tumor and inflammatory cells in regions of interest. This OM reported the number of participants classified as positive according to scoring algorithms and cut-offs established from external sources.

Participants were enrolled in the two cohorts based on BRCA 1/2 and ATM defect status assessed by the local laboratory. The participant BRCA and ATM status was assessed retrospectively by central laboratory, that may differ from the status assessed by the local laboratory. The ATM participants with a negative ATM status per the central laboratory were reported to have a positive ATM status per the local laboratory. Therefore, participants with negative ATM status might have been included in the ATM defect cohort. For defects in BRCA1, BRCA2 and ATM by central laboratory analysis, participants were classified as positive, negative, not analyzable or missing. The number of participants in each category of BRCA 1 defect, BRCA 2 defect, BRCA 1 or BRCA 2 defect and ATM defect were presented.

TMB was defined as the total number of mutations in the tumor genome, or number of mutations per megabase of DNA if derived from targeted sequencing. TMB categories were defined as high, low for a number of mutations per megabase >=10 and <10, respectively. The TMB category 'Not analyzable' included participants with available samples but not evaluable. The TMB category 'Missing' included participants with no sample available. The number of participants in each category at only baseline were tabulated.