Veliparib with carboplatin and paclitaxel in BRCA-mutated advanced breast cancer (BROCADE3): Final overall survival results from a randomized phase 3 trial

BACKGROUND

In the BROCADE3 study, the addition of veliparib to carboplatin plus paclitaxel resulted in a significant improvement in progression-free survival (PFS) compared with placebo plus carboplatin and paclitaxel, in patients with germline BRCA1 or BRCA2 (BRCA1/2)-mutated, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. We now report final overall survival (OS) data.

METHODS

BROCADE3 is a randomized phase 3 study that enrolled patients with BRCA1/2-mutated, HER2-negative advanced breast cancer who received ≤ 2 prior lines of chemotherapy for metastatic disease. Patients were randomized 2:1 to carboplatin and paclitaxel, dosed with either veliparib or matching placebo. OS was a secondary endpoint.

RESULTS

In the intention-to-treat population (N = 509), 337 patients were randomized to receive veliparib and 172 to placebo. Median OS was 32.4 months vs 28.2 months (hazard ratio, 0.916; 95% CI, 0.736-1.140; P = .434). The updated safety data for veliparib are consistent with those reported in the primary analysis; the addition of veliparib was generally well tolerated.

CONCLUSIONS

Final OS data indicate that the PFS improvement shown in the primary analysis did not translate into an OS benefit. The long survival times observed in both arms suggest that combination therapy with paclitaxel and carboplatin provides clinical benefit in the population of patients with BRCA1/2-mutated metastatic breast cancer.

Telisotuzumab vedotin (Teliso-V) monotherapy in patients (pts) with previously treated c-Met–overexpressing (OE) advanced non-small cell lung cancer (NSCLC)

9016

Background: Teliso-V is an antibody-drug conjugate composed of a c-Met antibody (ABT-700) and a microtubule inhibitor (monomethyl auristatin E). The phase 2 M14-239 trial (LUMINOSITY, NCT03539536) aims to identify the c-Met OE NSCLC populations best suited to Teliso-V (Stage 1) and expand selected groups for further evaluation of efficacy (Stage 2). In Stage 1, pts were enrolled into cohorts defined by histopathology (non-squamous [NSQ] or squamous [SQ]) and EGFR mutation status (mutant or wild type [WT]); NSQ cohorts were further divided in groups on the basis of c-Met expression (high or intermediate). Updated data from the fourth interim analysis (IA4) are presented. Methods: Pts had locally advanced/metastatic NSCLC, ≤2 prior lines of systemic therapy, ≤1 line of chemotherapy, and tumors that were c-Met OE by central immunohistochemistry (IHC; Ventana; Tucson, AZ). c-Met OE was defined for the NSQ cohort as ≥25% 3+ by IHC (high, ≥50% 3+; intermediate, 25 to <50% 3+) and for the SQ cohort as ≥75% 1+ by IHC. The planned enrollment was up to approximately 150 pts in Stage 1 and 160 pts in Stage 2. Teliso-V was dosed at 1.9 mg/kg IV Q2W. The primary endpoint is objective response rate (ORR) by independent central review. Secondary endpoints include duration of response (DOR). Results: As of data cutoff (27 May 2021), 136 pts were treated with Teliso-V; 122 were evaluable for ORR. ORR was 36.5% in the NSQ EGFR WT cohort (52.2% in c-Met high group and 24.1% in c-Met intermediate group), but was modest in the NSQ EGFR mutant and SQ cohorts. Efficacy data in groups/cohorts are in the Table. The most common any-grade adverse events (AEs) were peripheral sensory neuropathy (25.0%), nausea (22.1%), and hypoalbuminemia (20.6%). Grade 5 AEs considered possibly related to Teliso-V occurred in 2 pts (sudden death and pneumonitis in 1 pt each in the SQ cohort). Conclusions: Teliso-V demonstrated a promising ORR in pts with previously treated c-Met OE NSQ EGFR WT NSCLC; this cohort is currently expanding in Stage 2. ORR was modest in the cohorts of pts with c-Met OE NSQ EGFR mutant NSCLC and with c-Met OE SQ NSCLC; both cohorts have now met the protocol-specified stopping criteria and are no longer enrolling. The safety profile observed was consistent with IA3. Clinical trial information: NCT03539536. [Table: see text]

Impact of veliparib, paclitaxel dosing regimen, and germline BRCA status on the primary treatment of serous ovarian cancer - an ancillary data analysis of the VELIA trial

OBJECTIVE

In the Phase 3 VELIA trial (NCT02470585), veliparib added to carboplatin plus paclitaxel concomitantly and as maintenance for women with newly-diagnosed advanced ovarian cancer significantly improved progression-free survival (PFS) versus chemotherapy alone. Here we present exploratory analyses by paclitaxel dosing schedule and germline BRCA (gBRCA) status.

METHODS

Women with untreated ovarian carcinoma were randomized (1:1:1) to: veliparib during chemotherapy and maintenance (veliparib-throughout), veliparib during chemotherapy followed by placebo maintenance (veliparib-combination only), or placebo during chemotherapy and maintenance (control). Chemotherapy included carboplatin plus dose-dense (DD; weekly) or every-3-week (Q3W) paclitaxel (a stratification factor at randomization), selected at the investigator's discretion pre-randomization. PFS was assessed by paclitaxel dosing schedule using a Cox proportional hazard model adjusted by treatment arm and stratification factors; safety was analyzed based on paclitaxel dosing schedule and gBRCA status.

RESULTS

1132 patients were analyzed by paclitaxel schedule. Pooled treatment arms demonstrated longer median PFS with DD (n = 586) versus Q3W (n = 546) paclitaxel (ITT: 20.5 vs 15.7 months, hazard ratio [HR] 0.77; homologous recombination proficient cancer: 15.1 vs 11.8 months, HR 0.64; BRCAwt: 18.0 vs 12.9 months, HR 0.70). Comparison between arms favored veliparib-throughout versus control in both DD (PFS, 24.2 vs 18.3 months, hazard ratio 0.67) and Q3W (19.3 vs 14.6, hazard ratio 0.69) subgroups. DD paclitaxel was associated with higher incidence of Grade 3/4 neutropenia, fatigue, and anemia versus Q3W. There were no differences in toxicity between gBRCAm (n = 211) and gBRCAwt (n = 902) subgroups.

CONCLUSIONS

DD paclitaxel was tolerable and associated with longer PFS in the HR proficient and gBRCAwt groups, versus Q3W. gBRCA status did not impact safety.

Veliparib (V) monotherapy after progression on placebo (PL) + carboplatin/paclitaxel (CP) in patients with advanced HER2-negative gBRCA-associated breast cancer: Crossover outcomes and exploratory biomarker analyses in BROCADE3

1097

Background: In BROCADE3 (NCT02163694), addition of the PARP inhibitor (PARPi) V to CP improved PFS in patients (pts) with g BRCA-associated advanced breast cancer (hazard ratio 0.71 [95% CI 0.57–0.88], p = 0.002). Reversion mutations may account for resistance to platinum-based CT and PARPi. Efficacy, safety, and exploratory biomarker analyses for pts randomized to PL + CP who received crossover (Cx) V monotherapy after progression are reported. Methods: 513 total pts were randomized 2:1 to V + CP or PL + CP. V/PL, C, and P could be discontinued independently prior to progression, leading to varying platinum-free intervals at the time of progression. After progression, pts in the PL + CP arm could receive open-label Cx V monotherapy (300–400 mg BID continuous), beginning within 60 d of progression and continuing to second progression. Adverse events (AEs) and activity during Cx V were assessed. Exploratory analysis of BRCA reversion mutations restoring BRCA1/2 protein function that emerged during PL + CP treatment was performed on plasma circulating tumor DNA using targeted-amplicon next generation sequencing. Results: At data cutoff, 75 pts initially randomized to PL + CP had ≥1 dose of Cx V. Mean (range) duration of Cx V was 154 d (2–966). Activity during Cx V is in the Table. Mean (range) platinum-free interval at time of first dose of Cx V was 3.1 mos (0.4–10.9) vs 8.1 mos (1.0–34.9) in pts who had progressed vs had not progressed by 24 wks after first dose of Cx V. BRCA reversion analysis was completed for 18 Cx pts. Reversion mutations were identified in 1/18 pts (5.6%). This patient had Cx V duration of 19 d and had progressed by 24 wks. BRCA reversion analysis on additional Cx pts will be presented. Most common AEs during Cx V were nausea (61%), vomiting (29%), fatigue (24%), and diarrhea (21%). Any grade anemia, neutropenia, and thrombocytopenia occurred in 7%, 15%, and 7% of pts. Three pts (4%) experienced a convulsion event. Conclusions: Platinum-free interval may influence efficacy of subsequent PARPi. Impact of BRCA reversion mutations warrants further evaluation. Cross-resistance may limit PARPi efficacy after platinum failure. Clinical trial information: NCT02163694 . [Table: see text]

PFS by blinded independent central review (BICR) in the VELIA trial of veliparib (V) plus carboplatin/paclitaxel (CP) and as monotherapy in newly diagnosed patients (pts) with high-grade serous ovarian cancer (HGSC)

6077

Background: The phase III VELIA trial (NCT02470585) demonstrated statistically significant improvement in PFS per investigator (INV) for V added to CP and continued as maintenance (CPV-V) vs. CP alone in pts with newly diagnosed HGSC in the BRCA mutated ( BRCAm), homologous recombination deficient (HRD), and whole populations. Here we present pre-specified analyses of PFS per BICR. Methods: Pts with Stage III-IV HGSC received V or Placebo (PL) with CP (6 cycles) and as maintenance (30 additional cycles). Primary analysis of PFS by INV compared CPV-V to CP alone in the BRCAm, HRD, and whole populations. Exploratory analyses of PFS in BRCA wildtype (wt) and non-HRD HGSC were performed. Radiologic tumor assessments were also prospectively submitted to an independent central reviewer for blinded assessment per RECIST v 1.1. PFS per BICR and rates of concordance between INV and BICR for determination of disease progression were analyzed. Safety data from the primary analysis were previously reported. Results: 1140 total pts were enrolled (CPV-V 382; CP 375). In the whole population, 26% of HGSCs were BRCAm and 55% were HRD. Concordance rates between INV and BICR were 68-85% by arm for each population. Analyses of PFS per BICR and per INV were consistent (Table). PFS was prolonged in the CPV-V vs. CP arm in all primary and exploratory populations assessed. Conclusions: Analyses of PFS per BICR supported the primary analysis of PFS per INV in the BRCAm, HRD, and whole populations, as well as exploratory BRCAwt and non-HRD populations. Median PFS per BICR was longer compared to PFS per INV assessments in all populations and in both arms. These findings support the reliability of PFS by INV in ovarian cancer trials. Alternate strategies like audits may be appropriate to support PFS by INV with less time and expense than full BICR. Clinical trial information: NCT02470585. [Table: see text]

Veliparib (V) monotherapy (monoTx) following combination therapy with V + carboplatin/paclitaxel (CP) in patients with gBRCA-associated advanced breast cancer: Exploratory results from BROCADE3

1091

Background: In BROCADE3 (NCT02163694), addition of PARP inhibitor V to CP resulted in improved progression-free survival (PFS) (HR 0.71 [95% CI 0.57−0.88], p=0.002) in patients (pts) with advanced HER2-negative breast cancer and g BRCA1/2 mutation. A subset of pts transitioned to V/placebo (PL) monoTx at an intensified dose/schedule after CP discontinuation prior to progression (investigator discretion). Here, we evaluate the impact of this transition on efficacy and safety. Methods: Pts were randomized 2:1 to CP with V (n=337) or PL (n=172). V (120 mg po BID) or PL was given on Days (D) −2 to 5, C (AUC 6) on D1, and P (80 mg/m2) on D1, 8, and 15 (21-day cycles). Pts who transitioned to monoTx received V/PL 300-400mg BID daily until progression. A Cox model with a time varying covariate indicating transition from V/PL with CP to V/PL monoTx was fit to estimate treatment effect during combination and monoTx phases. PFS by cycles of CP prior to monoTx and AEs during monoTx are summarized. Results: A subgroup of 136 (40%) and 58 (34%) pts on the V and PL arms, respectively, received monoTx. When a Cox model with a time-varying covariate was fit for PFS (per investigator), the nominal P-value for treatment by covariate interaction was 0.038. The HRs (95% CI) for V vs PL during combination therapy and monoTx were 0.81 (0.62–1.06) and 0.49 (0.33–0.73). The Table summarizes PFS by cycles of C and/or P prior to monoTx. Common AEs (>20% of pts) during V or PL monoTx were nausea (52%/10%), fatigue (23%/12%), headache (21%/17%), and diarrhea (21%/9%). Seizures (2.2%/0%) were reported during monoTx. Rates of cytopenias for V or PL monoTx were: anemia 12%/14%; neutropenia 13%/12%; and thrombocytopenia 10%/5%. Conclusions: These analyses suggest that pts treated with V + CP derive benefit from both combination therapy as well as V monoTx after CP discontinuation. Pts receiving V monoTx after ≤ 6 cycles of VCP experienced a similar benefit to those who transitioned to monoTx after 7–12 cycles of VCP, suggesting that V maintenance therapy may be suitable following a limited duration of combination therapy. Clinical trial information: NCT02163694 . [Table: see text]

Impact of cirrhosis in patients undergoing laparoscopic liver resection in a nationwide multicentre survey

BACKGROUND

The aim was to analyse the impact of cirrhosis on short-term outcomes after laparoscopic liver resection (LLR) in a multicentre national cohort study.

METHODS

This retrospective study included all patients undergoing LLR in 27 centres between 2000 and 2017. Cirrhosis was defined as F4 fibrosis on pathological examination. Short-term outcomes of patients with and without liver cirrhosis were compared after propensity score matching by centre volume, demographic and tumour characteristics, and extent of resection.

RESULTS

Among 3150 patients included, LLR was performed in 774 patients with (24·6 per cent) and 2376 (75·4 per cent) without cirrhosis. Severe complication and mortality rates in patients with cirrhosis were 10·6 and 2·6 per cent respectively. Posthepatectomy liver failure (PHLF) developed in 3·6 per cent of patients with cirrhosis and was the major cause of death (11 of 20 patients). After matching, patients with cirrhosis tended to have higher rates of severe complications (odds ratio (OR) 1·74, 95 per cent c.i. 0·92 to 3·41; P = 0·096) and PHLF (OR 7·13, 0·91 to 323·10; P = 0·068) than those without cirrhosis. They also had a higher risk of death (OR 5·13, 1·08 to 48·61; P = 0·039). Rates of cardiorespiratory complications (P = 0·338), bile leakage (P = 0·286) and reoperation (P = 0·352) were similar in the two groups. Patients with cirrhosis had a longer hospital stay than those without (11 versus 8 days; P = 0·018). Centre expertise was an independent protective factor against PHLF in patients with cirrhosis (OR 0·33, 0·14 to 0·76; P = 0·010).

CONCLUSION

Underlying cirrhosis remains an independent risk factor for impaired outcomes in patients undergoing LLR, even in expert centres.

Abstract P4-22-02: Evaluation of veliparib (V) and temozolomide (TMZ) in a phase 2 randomized study of the efficacy and tolerability of V+TMZ or carboplatin (C) and paclitaxel (P) vs placebo (Plc)+C/P in patients (pts) with BRCA1 or BRCA2 mutations and metastatic breast cancer

Background: V is a potent, poly(ADP-ribose) polymerase (PARP) inhibitor that obstructs DNA damage repair. BRCA1/2 tumors are defective in homologous recombination, which leads to more error-prone mechanisms of DNA repair and increased sensitivity to PARP inhibition. V enhances the antitumor activity of alkylating agents such as TMZ in preclinical models. In addition, V+TMZ showed promising activity in a single-arm phase 2 study in pts with BRCA1/2 mutations. This phase 2 trial (NCT01506609) investigated the efficacy and tolerability of V+TMZ (or V+C/P) compared to Plc+C/P in pts with locally recurrent or metastatic breast cancer harboring a BRCA1 or BRCA2 mutation. Results from the primary analysis for the V+TMZ arm vs Plc+C/P are presented, and the V+C/P vs Plc+C/P results will be presented separately.

Methods: Male and female pts aged ≥18 years with histologically confirmed locally recurrent or metastatic breast cancer were randomized 1:1:1 to: 1) V 40 mg BID D1–7 + TMZ 150–200 mg/m2 QD D1–5, 28-D cycle; 2) V 120 mg BID D1–7 + C AUC 6, D3 and P 175 mg/m2, D3, 21-D cycle; 3) placebo BID D1–7 + C/P. Key eligibility criteria included known deleterious BRCA1/2 mutation, ≤2 prior chemotherapies for metastatic disease, no prior platinum agent, and no CNS metastases. Randomization was stratified by hormone receptor status, prior cytotoxic therapy (yes vs no), and ECOG PS (0–1 vs 2). The primary endpoint was progression-free survival (PFS) per RECIST 1.1 by independent review. Overall survival (OS), objective response rate (ORR), and safety/tolerability were also evaluated.

Results: A total of 290 pts (284 BRCA+ per central lab) were randomized (V+TMZ, n=94 [91 BRCA+]). Baseline demographics and disease characteristics were comparable among treatment arms; 41.3% of pts had triple-negative breast cancer (TNBC) and 31.7% had received &gt;2 prior regimens. Median study drug exposure was 6 cycles for the V+TMZ arm and 10 cycles for the Plc+C/P arm. Median PFS, median OS (interim), and ORR for V+TMZ were inferior to Plc+C/P (PFS 7.4 vs 12.3 mo, OS 19.1 vs 25.0 mo, and ORR 28.6% vs 61.3%). In pts with TNBC, median PFS was 5.5 (3.1–8.5) mo; 8.4 (6.8–10.6) mo for pts with non-TNBC. Treatment-emergent adverse events (AEs) of interest occurring differentially with V+TMZ are shown in Table 1. Grade ≥3 AEs in ≥30% of pts in the V+TMZ arm were thrombocytopenia (48%) and neutropenia (37%).

Conclusions: V+TMZ provided durable responses, with less neutropenia, alopecia, and neuropathy than Plc+C/P; however, PFS, OS, and ORR were inferior in the TMZ arm compared to C/P.

Table 1Treatment-Emergent AEs, n (%)V+TMZ, n=93Plc+C/P, n=96Neutropenia46 (50)71 (74)Alopecia10 (11)55 (57)Peripheral neuropathy11 (12)56 (58)Thrombocytopenia73 (79)67 (70)Nausea70 (75)56 (58)

Citation Format: Diéras V, Han HS, Robson ME, Palácová M, Marcom PK, Jager A, Bondarenko I, Citrin D, Campone M, Telli ML, Domchek SM, Friedlander M, Kaufman B, Ratajczak C, Coates A, Bonnet P, Qin Q, Qian J, Giranda VL, Shepherd SP, Puhalla S, Isakoff SJ. Evaluation of veliparib (V) and temozolomide (TMZ) in a phase 2 randomized study of the efficacy and tolerability of V+TMZ or carboplatin (C) and paclitaxel (P) vs placebo (Plc)+C/P in patients (pts) with BRCA1 or BRCA2 mutations and metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-02.

Aberrant dendritic cell function conditions Th2-cell polarization in allergic rhinitis

BACKGROUND

Myeloid (m) and plasmacytoid (p) dendritic cells (DCs) regulate immune responses to allergens, whereas it remains unclear whether abnormal DC function characterizes patients with airway allergy and whether putative dysfunction exists only in target organs. To evaluate DC function from patients with allergic rhinitis (AR), we assessed nasal, cutaneous as well as blood DCs after in vivo and in vitro allergen challenge, respectively.

METHODS

DCs were immunostained in nasal and skin tissues, and cytokine expression was assessed by dual immunofluorescence. Cytokine production and regulation of cocultured peripheral CD4+ T cells were assayed by ELISA.

RESULTS

In AR patients, local allergen challenge resulted in increases in pDC and mDC numbers at 8 h in the nasal mucosa and at 8-48 h in the skin. Defects in IL-10 and IFN-α were observed in both organs from AR. Blood mDCs from AR exhibited reduced IL-10 and IL-12 expression. The capacity of activated pDCs from AR to produce IFN-α and to trigger IL-10 by allogeneic CD4(+) T cells was diminished, whereas mDCs from these patients supported Th2- and Th17-cell differentiation.

CONCLUSION

In allergic rhinitis, DCs are altered not only locally but also in the systemic circulation. mDCs and pDCs increased in airway and skin tissues exposed to the allergen and displayed reduced production of IL-10 and 'type 1 signals' (IL-12, IFN-α) both locally and in blood. Functional studies showed that this results in preferential Th2/Th17-cell polarization and impaired generation by blood DCs of IL-10+ T cells, linking systemic DC dysfunction and biased T-cell responses.

Abstract 3077: Nek3/Vav2 modulation of the expression of genes involved in breast cancer pathogenesis

The pituitary hormone prolactin (PRL) is generally recognized for its role in breast growth and differentiation; however, a role for PRL in the pathogenesis of breast cancer has emerged from epidemiological studies and basic science research using both human breast cancer cells and animal models. Activation of the prolactin receptor (PRLr) by PRL contributes to the growth, survival, and motility of human breast cancer cells. PRLr stimulation by PRL results in the activation of multiple signaling complexes including serine/threonine kinase Nek3 and guanine nucleotide exchange factor Vav2. Nek3 is necessary for the activation of Vav2, and Nek3 knockdown results in decreased cytoskeletal re-organization, cell motility, and cell invasion in PRL-stimulated human breast cancer cells. The overexpression of a kinase inactive form of Nek3 in human breast cancer cells results in increased apoptosis, indicating a pro-survival function for Nek3. Furthermore, Nek3 expression is increased in malignant vs. normal human breast tissue. These data make the Nek3/Vav2 complex an interesting target for novel breast cancer therapeutics. To this end, a greater understanding of the role of Nek3/Vav2 in breast cancer pathogenesis is necessary. We hypothesized that the Nek3/Vav2 complex modulates PRL-driven expression of genes involved in the pathogenesis of breast cancer. In these studies, luciferase assays and quantitative PCR were used to evaluate the effects of gain- or loss-of-function of Nek3/Vav2 on the expression of CISH (cytokine-inducible SH2-containing protein). Gain- or loss-of-function of Nek3/Vav2 was found to alter the expression of CISH in response to PRL in both MCF7 and T47D human breast cancer cell lines. The CISH promoter has 4 binding sites for the transcription factor Stat5, which is known to contribute to malignant transformation and tumor growth in breast cancer. Luciferase assay showed that gain- or loss-of-function of Nek3 was also found to alter the activation of a reporter construct containing the lactogenic hormone response element which consists of six tandem Stat5 DNA-binding elements. This suggests that Nek3/Vav2 modulates the PRL-driven expression of CISH by regulating activity of the transcription factor Stat5. Gain- or loss-of-function of Nek3/Vav2 was not found to alter the subcellular localization of Stat5 in response to PRL. Ongoing studies are examining the mechanism of Nek3/Vav2 modulation of PRL-responsive gene expression in breast cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3077. doi:1538-7445.AM2012-3077

Tumor necrosis factor-related apoptosis inducing ligand expression and activity in hen granulosa cells

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) represents one of several cytokine members of the tumor necrosis factor superfamily reported to initiate apoptosis in a wide range of transformed, but not most normal, cell types. The present studies were conducted to evaluate the potential for TRAIL to promote apoptotic cell death in differentiated granulosa cells collected from hen preovulatory follicles. While mRNA encoding critical components (including TRAIL) required for a functional extrinsic cell death pathway are expressed in granulosa cells, TRAIL treatment by itself fails to induce either caspase-3 activity or a decrease in cell viability. On the other hand, preculture of cells with the conventional chemotherapeutic, cisplatin, or the 20S proteosome inhibitor, Z-LLF-CHO, sensitizes granulosa cells to TRAIL as evidenced by enhanced caspase-3 activity after 4 h of culture and loss of cell viability after 24 h when compared with either cisplatin or Z-LLF-CHO treatment alone. Moreover, the sensitizing effect of Z-LLF-CHO on TRAIL-induced loss of cell viability is prevented by the selective caspase-8 inhibitor, Z-IETD-FMK. Interestingly, TRAIL mRNA expression is elevated both in prehierarchal follicles undergoing spontaneous atresia and in prehierarchal follicles induced to undergo atresia for 6 h in vitro. In summary, the data demonstrate the presence of a functional TRAIL signaling pathway in hen granulosa cells, and are consistent with the possibility that TRAIL signaling may directly or indirectly participate in the process of follicle atresia in vivo.