A phase I study of PF-06647263, a novel EFNA4-ADC, in patients with metastatic triple negative breast cancer

2511

Background: PF-06647263 is an anti-Ephrin-A4 (EFNA4) antibody drug conjugate (ADC) composed of a humanized mAb, a hydrazone cleavable linker, and calicheamicin, a potent DNA damaging agent. Higher levels of EFNA4 expression have been shown in tumor versus normal tissue, including in two thirds of triple negative breast cancers (TNBC). In vivo preclinical studies demonstrate PF-06647263 induced tumor regression in TNBC models. Methods: In Part 1 of a dose escalation, cohorts of 2-12 patient (pts) with solid tumors that were unselected for EFNA4 expression received escalating doses of PF-06647263 once every 3 weeks (Q3W, Cohort A) or weekly (QW, Cohort B). Escalations were based on mTPI design. An expansion cohort enrolled TNBC patients (n=12) unselected for EFNA4 expression. Efficacy, safety, EFNA4 RNA expression, pharmacokinetic (PK) and anti-drug antibody development were assessed. Results: Part 1 (dose escalation):A total of 48 pts (25 in A and 23 in B) wereenrolled. The most common treatment related adverse events (AE) were fatigue (65%), and nausea (60%), thrombocytopenia (40%), and decreased appetite (38%). DLTs were observed in 6 and 2 pts in the Q3W and QW regimens, respectively. One confirmed VOD and one suspected VOD were observed in two patients in the Q3W schedule. The maximum tolerated dose (and RP2D) was determined to be 0.015 mg/kg QW. Confirmed partial responses (PR) were observed in 5 pts (3 Ovarian Ca and 2 TNBC). Part 2 (TNBC dose expansion at RP2D)data are available on 10 of 12 pts treated (2 ongoing). The most common adverse events (AE) were nausea (40%), asthenia (30%), vomiting (30%) and mucosal inflammation (30%). No objective RECIST response was observed; there was no dependency with duration of treatment relative to EFNA4 expression. Conclusions: In Part 1 of this study, PF-06647263 was generally well-tolerated in the QW schedule and some anti-tumor activity was observed in heavily pretreated pts with EFNA4 unselected advanced malignancies. However, in the expansion cohort (Part 2) at RP2D in TNBC no objective responses were observed regardless of EFNA4 expression. Final safety, efficacy, expression and PK data will be reported at the meeting. Clinical trial information: NCT02078752.

Abstract P4-22-13: Everolimus plus trastuzumab and paclitaxel as first-line therapy in women with HER2+ advanced breast cancer: Overall survival results from BOLERO-1

Background

Everolimus (EVE), an mTOR inhibitor has shown activity in HER2+ advanced breast cancer (ABC) in both preclinical and clinical studies. In the pivotal BOLERO-1 trial (NCT00876395), the progression-free survival (PFS) was not significantly different between the EVE + trastuzumab (TRAS) + paclitaxel (PAC) combination and placebo (PBO) + TRAS + PAC in the full HER2+ population (EVE, 15.0 mo vs PBO, 14.5 mo; HR=0.89; 95% CI: 0.73-1.08; p=0.1166). Although not reaching protocol defined level for statistical significance, the hormone receptor negative (HR-) subpopulation appeared to benefit from EVE, with a 7.2 mo PFS benefit vs PBO arm (EVE, 20.3 mo vs PBO, 13.1 mo; HR=0.66; 95% CI: 0.48-0.91; p=0.0049). The final exploratory overall survival (OS) analysis from the study is presented here.

Methods

In this phase 3 randomized trial, 719 women with HER2+ ABC without prior TRAS or chemotherapy in the metastatic setting were randomized 2:1 to receive either EVE (10 mg/d) or placebo (PBO) and weekly PAC+TRAS, stratified by visceral metastasis (lung, liver, peritoneal or pleural: yes vs no) and prior adjuvant or neo-adjuvant treatment with TRAS (yes vs no). As the primary objectives (PFS on full population and on HR- subpopulation) of BOLERO-1 were not met, the key secondary endpoint of OS was not formally statistically tested. However, given the results of PFS, in particular in the HR- subpopulation, a change to the OS analysis plan was made by introducing one final exploratory OS analysis at the time of study termination.

Results

At data cutoff (Dec 31, 2015), the median duration of exposure was 40.8 weeks (range: 0.6-320.4) in the EVE arm and 48.1 weeks (range: 1.1-308.0) in the PBO arm. After a median follow-up of 60.3 mo, 350 deaths were recorded in the full population, 238 (49.6%) in the EVE arm and 112 (46.9%) pts in the PBO arm. In the full population, the median OS was comparable in the EVE vs PBO arms (48.6 mo vs 50.0 mo respectively; HR = 1.13; 95% CI: 0.90-1.42). In the HR- subpopulation, 138 deaths were recorded; 88 (42.3%) pts in the EVE arm and 50 (48.5%) pts in the PBO arm. In the HR- subpopulation, the median OS in the EVE arm was longer compared to PBO arm (57.0 mo vs 41.6 mo respectively; HR = 0.83; 95% CI: 0.59-1.18). Stomatitis, diarrhea, alopecia, cough, rash, pyrexia, neutropenia, and fatigue were the most frequent adverse events (AEs) reported in EVE arm (≥35%). AEs leading to dose interruption and/or change were reported in 441 (93.4%) pts in EVE arm and 165 (69.3%) pts in the PBO arm respectively. Overall, AEs leading to treatment discontinuation were reported in 262 (55.5%) pts in EVE arm and 98 (41.2%) pts in PBO arm. Serious AEs were reported in 171 (36.2%) pts in the EVE arm and 40 (16.8%) pts in the PBO arm respectively. On treatment AE related deaths were reported for 3.6% pts in the EVE arm and 0% pts in the PBO arm.

Conclusions

The median OS was similar in the EVE vs PBO arms for overall population. However, a prolongation of 15.4 mo in median OS of HR- subpopulation was observed in the EVE arm vs PBO arm in this exploratory analysis. Pts in the EVE arm had a manageable safety, consistent with the safety profile of EVE and no new safety signals were identified.

Citation Format: Yardley D, Hurvitz S, Jiang Z-f, Toi M, Burris H, Buyse M, Slamon D, Makhson A, Elsaid A, Lerzo G, Hellerstedt B, Nuzzo F, Sohn J, Manzyuk L, Cabaribere D, Lincy J, Weimann A, Noel-Baron F, Pacaud L, Andre F. Everolimus plus trastuzumab and paclitaxel as first-line therapy in women with HER2+ advanced breast cancer: Overall survival results from BOLERO-1 [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 P4-22-13.

Abstract P6-12-04: Phase 1 study of the antibody-drug conjugate (ADC) SGN-LIV1A in patients with heavily pretreated metastatic breast cancer

Background

LIV-1, a transmembrane protein and downstream target of STAT3, is highly expressed in breast cancer cells. It is associated with lymph node involvement and metastatic progression. SGN-LIV1A is an anti-LIV-1 antibody conjugated via a protease-cleavable linker to monomethyl auristatin E (MMAE). Upon binding to cell-surface LIV-1, SGN-LIV1A is internalized and releases MMAE, which binds to tubulin and induces G2/M arrest and apoptosis.

Methods

This is an ongoing, phase 1 dose-escalation study evaluating safety, tolerability, pharmacokinetics, and antitumor activity of SGN-LIV1A (q3 wks IV) in women with LIV-1-positive, unresectable, locally advanced or metastatic breast cancer (LA/MBC) (NCT01969643). Patients (pts) with measurable disease and ≥2 prior cytotoxic regimens for LA/MBC were eligible. Pts with ≥Grade 2 neuropathy were excluded. Response was assessed per RECIST v1.1; pts with stable disease (SD) or better could continue treatment until disease progression or intolerable toxicity. At completion of dose escalation in hormone receptor-positive/HER2-negative (HR+/HER2–) and triple-negative (TN) pts, expansion cohorts were opened to further evaluate safety and antitumor activity of monotherapy in TN pts and combination therapy with trastuzumab (Tz) in HER2-positive (HER2+) pts. Pre- and post-treatment tumor biopsies were done to evaluate LIV-1 expression and other correlative endpoints.

Results

To date, 39 pts (18 HR+/HER2–, 21 TN) have received a median of 3 cycles (range, 1–10) of SGN-LIV1A monotherapy at doses of 0.5–2.8 mg/kg. Median age was 57 yrs (range, 33–79). At baseline, pts had a median of 4 prior cytotoxic regimens for LA/MBC (range, 2–8); 36 had visceral disease and 25 had bone involvement. No dose-limiting toxicities (DLT) occurred in 19 DLT-evaluable pts; maximum tolerated dose was not exceeded at 2.8 mg/kg. Treatment-emergent adverse events (AEs) reported in ≥30% of pts were: fatigue (64%), nausea (54%), alopecia (46%), decreased appetite (41%), constipation (39%), neutropenia (33%), and vomiting (31%). Peripheral neuropathy was reported in 9 pts (23%). Most AEs were Grade 1/2, except neutropenia (all ≥Grade 3). Four pts discontinued treatment due to AEs (acute respiratory distress syndrome, nausea, pneumonia, tachycardia). In dose escalation, modest activity was observed in 17 efficacy evaluable (EE) HR+/HER2- pts, with a disease control rate (DCR) of 59% (10 SD), including 1 pt with SD≥24 wks. Among the 17 EE TN pts (dose escalation plus cohort expansion), the overall response rate (ORR) was 41% (7 PR), DCR was 82% (7 PR, 7 SD) and clinical benefit rate (CBR=OR+SD≥24 wks) was 53% (9 pts). For TN pts, median PFS was 17.1 wks (95% CI: 6.0, 18.4); 6 pts remain on treatment.

Of 281 MBC tumor samples evaluated for LIV-1, 93% were positive; 81% had moderate-to-high expression (H-score ≥100).

Conclusions

LIV-1 is expressed in almost all MBC tumors. SGN-LIV1A monotherapy has been generally well tolerated and shown encouraging antitumor activity in heavily pretreated TN MBC, with a PR rate of 41% and a CBR at ≥24 wks of 53%. Response duration data continue to evolve. Enrollment continues in the TN monotherapy expansion cohort and the HER2+ combination cohort with Tz.

Citation Format: Forero-Torres A, Modi S, Specht J, Miller K, Weise A, Burris III H, Liu M, Krop I, Pusztai L, Kostic A, Li M, Mita M. Phase 1 study of the antibody-drug conjugate (ADC) SGN-LIV1A in patients with heavily pretreated 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 P6-12-04.

Comparative Efficacy and Safety of Adjuvant Letrozole Versus Anastrozole in Postmenopausal Patients With Hormone Receptor-Positive, Node-Positive Early Breast Cancer: Final Results of the Randomized Phase III Femara Versus Anastrozole Clinical Evaluation (FACE) Trial

Purpose The Letrozole (Femara) Versus Anastrozole Clinical Evaluation (FACE) study compared the efficacy and safety of adjuvant letrozole versus anastrozole in postmenopausal patients with hormone receptor (HR) -positive and node-positive early breast cancer (eBC). Methods Postmenopausal women with HR-positive and node-positive eBC were randomly assigned to receive adjuvant therapy with either letrozole (2.5 mg) or anastrozole (1 mg) once per day for 5 years or until recurrence of disease. Patients were stratified on the basis of the number of lymph nodes and human epidermal growth factor receptor 2 status. The primary end point was 5-year disease-free survival (DFS), and the key secondary end points were overall survival and safety. Results A total of 4,136 patients were randomly assigned to receive either letrozole (n = 2,061) or anastrozole (n = 2,075). The final analysis was done at 709 DFS events (letrozole, 341 [16.5%]; anastrozole, 368 [17.7%]). The 5-year estimated DFS rate was 84.9% for letrozole versus 82.9% for anastrozole arm (hazard ratio, 0.93; 95% CI, 0.80 to 1.07; P = .3150). Exploratory analysis showed similar DFS with letrozole and anastrozole in all evaluated subgroups. The 5-year estimated overall survival rate was 89.9% for letrozole versus 89.2% for anastrozole arm (hazard ratio, 0.98; 95% CI, 0.82 to 1.17; P = .7916). Most common grade 3 to 4 adverse events (> 5% of patients) reported for letrozole versus anastrozole were arthralgia (3.9% v 3.3%, and 48.2% v 47.9% for all adverse events), hypertension (1.2% v 1.0%), hot flushes (0.8% v 0.4%), myalgia (0.8% v 0.7%), dyspnea (0.8% v 0.5%), and depression (0.8% v 0.6%). Conclusion Letrozole did not demonstrate significantly superior efficacy or safety compared with anastrozole in postmenopausal patients with HR-positive, node-positive eBC.

Molecular Alterations and Everolimus Efficacy in Human Epidermal Growth Factor Receptor 2-Overexpressing Metastatic Breast Cancers: Combined Exploratory Biomarker Analysis From BOLERO-1 and BOLERO-3

PURPOSE

Two recent phase III trials, BOLERO-1 and BOLERO-3 (Breast Cancer Trials of Oral Everolimus), evaluated the addition of everolimus to trastuzumab and chemotherapy in human epidermal growth factor receptor 2-overexpressing advanced breast cancer. The current analysis aimed to identify biomarkers to predict the clinical efficacy of everolimus treatment.

METHODS

Archival tumor samples from patients in BOLERO-1 and BOLERO-3 were analyzed using next-generation sequencing, immunohistochemistry, and Sanger sequencing.

RESULTS

Biomarker data were available for 549 patients. PIK3CA activating mutations and PTEN loss were reported in 30% and 16% of BOLERO-1 samples and in 32% and 12% of BOLERO-3 samples, respectively. PI3K pathway was hyperactive (PIK3CA mutations and/or PTEN loss and/or AKT1 mutation) in 47% of BOLERO-1 and 41% of BOLERO-3 samples. In both studies, differential progression-free survival (PFS) benefits of everolimus were consistently observed in patient subgroups defined by their PI3K pathway status. When analyzing combined data sets of both studies, everolimus was associated with a decreased hazard of progression in patients with PIK3CA mutations (hazard ratio [HR], 0.67; 95% CI, 0.45 to 1.00), PTEN loss (HR, 0.54; 95% CI, 0.31 to 0.96), or hyperactive PI3K pathway (HR, 0.67; 95% CI, 0.48 to 0.93). Patients with wild-type PIK3CA (HR, 1.10; 95% CI, 0.83 to 1.46), normal PTEN (HR, 1.00; 95% CI, 0.80 to 1.26), or normal PI3K pathway activity (HR, 1.19; 95% CI, 0.87 to 1.62) did not derive PFS benefit from everolimus.

CONCLUSION

This analysis, although exploratory, suggests that patients with human epidermal growth factor receptor 2-positive advanced breast cancer having tumors with PIK3CA mutations, PTEN loss, or hyperactive PI3K pathway could derive PFS benefit from everolimus.

Phase I Study of LY2606368, a Checkpoint Kinase 1 Inhibitor, in Patients With Advanced Cancer

PURPOSE

The primary objective was to determine safety, toxicity, and a recommended phase II dose regimen of LY2606368, an inhibitor of checkpoint kinase 1, as monotherapy.

PATIENTS AND METHODS

This phase I, nonrandomized, open-label, dose-escalation trial used a 3 + 3 dose-escalation scheme and included patients with advanced solid tumors. Intravenous LY2606368 was dose escalated from 10 to 50 mg/m(2) on schedule 1 (days 1 to 3 every 14 days) or from 40 to 130 mg/m(2) on schedule 2 (day 1 every 14 days). Safety measures and pharmacokinetics were assessed, and pharmacodynamics were measured in blood, hair follicles, and circulating tumor cells.

RESULTS

Forty-five patients were treated; seven experienced dose-limiting toxicities (all hematologic). The maximum-tolerated doses (MTDs) were 40 mg/m(2) (schedule 1) and 105 mg/m(2) (schedule 2). The most common related grade 3 or 4 treatment-emergent adverse events were neutropenia, leukopenia, anemia, thrombocytopenia, and fatigue. Grade 4 neutropenia occurred in 73.3% of patients and was transient (typically < 5 days). Febrile neutropenia incidence was low (7%). The LY2606368 exposure over the first 72 hours (area under the curve from 0 to 72 hours) at the MTD for each schedule coincided with the exposure in mouse xenografts that resulted in maximal tumor responses. Minor intra- and intercycle accumulation of LY2606368 was observed at the MTDs for both schedules. Two patients (4.4%) had a partial response; one had squamous cell carcinoma (SCC) of the anus and one had SCC of the head and neck. Fifteen patients (33.3%) had a best overall response of stable disease (range, 1.2 to 6.7 months), six of whom had SCC.

CONCLUSION

An LY2606368 dose of 105 mg/m(2) once every 14 days is being evaluated as the recommended phase II dose in dose-expansion cohorts for patients with SCC.

Abstract 5514: Pharmacokinetics of BIND-014 (docetaxel nanoparticles for injectable suspension) in preclinical species and patients with advanced solid tumors

Background: BIND-014 is a novel, prostate-specific membrane antigen (PSMA)targeted, polymeric nanoparticle-containing docetaxel (DTXL). PSMA is expressed on prostate cancer cells and on vasculature of non-prostate solid tumors. The PK profile of BIND-014 is characterized by reduced CL and V(D). These characteristics together with PSMA targeting, potentially lead to greater tumor uptake and improved activity of BIND-014 compared to conventional solvent-based DTXL (sb-DTXL). In a Phase 1 clinical trial, BIND-014 was well tolerated and displayed multiple clinical response.

Methods: Preclinical PK studies were performed in tumor-bearing mice and cynomolgus monkeys. Clinical PK was measured in patients with solid tumors. BIND-014 was administered intravenously and blood samples were collected up to 96 hours post-dose. Plasma was analyzed for total and encapsulated DTXL using LC/MS-MS. PK parameters were determined by non-compartmental analysis.

Results: BIND-014 preclinical and clinical PK demonstrated monophasic plasma concentration-time profiles were well differentiated from sb-DTXL. BIND-014 displayed higher Cmax and AUC with reduced CL and V(D) compared to sb-DTXL. In all species, the V(D) of BIND-014 was close to the blood volume. Evaluation of encapsulated DTXL plasma concentrations in patients and cynomolgus monkeys demonstrated means of 91% and 92% of total DTXL, respectively, indicating that most circulating DTXL was encapsulated in nanoparticles.

Conclusion: BIND-014 displays a PK profile well differentiated from sb-DTXL and consistent with retention of BIND-014 nanoparticles in the blood compartment and controlled release of DTXL. In contrast, sb-DTXL displays rapid CL and a high V(D). The PK characteristics of BIND-014 are associated with increased intratumoral DTXL concentrations and tumor growth suppression in preclinical models, and may lead to greater efficacy in patients.

Preclinical and clinical PK differences between BIND-014 and sb-DTXLTumor bearing mouseCynomolgus monkeysPatients with solid tumorsBIND-014sb-DTXLΔBIND-014sb-DTXLΔBIND-014sb-DTXLΔDose (mg/m2)304060C(max) (μg/mL)100.80.7713065.52.72423.81.515.3AUC(0-t) (μg•h/mL)684.72.1326431.04.1105229.22.8580.4t(½) (h)4.38.80.54.719.40.26.1180.3CL (L/h/m2)0.04414.00.0030.0929.40.010.2210.01V(D) (L/m2)53.353.30.0040.63264.40.0023.61130.03

Citation Format: Jason Summa, Daniel Von Hoff, Jasgit Sachdev, Monica Mita, Patricia LoRusso, Peter Eisenberg, Howard Burris, Lowell Hart, Hagop Youssoufian, Donald Parsons, Susan Low. Pharmacokinetics of BIND-014 (docetaxel nanoparticles for injectable suspension) in preclinical species and patients with advanced solid tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5514. doi:10.1158/1538-7445.AM2015-5514

Phase I dose-escalation study of pilaralisib (SAR245408, XL147), a pan-class I PI3K inhibitor, in combination with erlotinib in patients with solid tumors

BACKGROUND

This phase I study evaluated the maximum tolerated dose (MTD), safety, pharmacokinetics (PK), and pharmacodynamics of pilaralisib (SAR245408), an oral pan-class I phosphoinositide 3-kinase (PI3K) inhibitor, in combination with erlotinib, an epidermal growth factor receptor (EGFR) inhibitor.

METHODS

In a 3 + 3 dose-escalation study, patients with advanced solid tumors received pilaralisib capsules once daily (21 days per 28-day cycle; 50-600 mg) plus erlotinib tablets once daily (28 days per 28-day cycle; 100 or 150 mg). An MTD expansion cohort of patients with non-small cell lung cancer who had previously received treatment with an EGFR inhibitor was included.

RESULTS

Thirty-five patients were enrolled. Only one patient had an EGFR activating mutation. One dose-limiting toxicity was reported (grade 4 drug reaction or rash with eosinophilia and systemic symptoms). MTD was pilaralisib 400 mg plus erlotinib 150 mg. The most commonly reported treatment-related adverse events were rash (62.9%), diarrhea (42.9%), and fatigue (40.0%). Pilaralisib PK findings were consistent with previous studies, suggesting erlotinib had no effect on pilaralisib pharmacokinetics. Pharmacodynamic analyses indicated moderate inhibition of PI3K, mitogen-activated protein kinase, and EGFR pathways. Of 27 evaluable patients, one had a partial response (3.7%) and 14 (51.9%) had stable disease. There was no association between molecular alterations of PI3K pathway components and clinical activity.

CONCLUSION

Pilaralisib plus erlotinib had limited antitumor activity. Safety findings were similar to recent studies of single-agent pilaralisib or other PI3K inhibitors.

Phase I study of olaparib plus gemcitabine in patients with advanced solid tumours and comparison with gemcitabine alone in patients with locally advanced/metastatic pancreatic cancer

BACKGROUND

Olaparib (Lynparza) is an oral poly(adenosine diphosphate [ADP]-ribose) polymerase inhibitor that induces synthetic lethality in cancers with homologous recombination defects.

PATIENTS AND METHODS

In this phase I, dose-escalation trial, patients with advanced solid tumours received olaparib (50-200 mg capsules b.i.d.) continuously or intermittently (days 1-14, per 28-day cycle) plus gemcitabine [i.v. 600-800 mg/m(2); days 1, 8, 15, and 22 (cycle 1), days 1, 8, and 15 (subsequent cycles)] to establish the maximum tolerated dose. A separate dose-escalation phase evaluated olaparib in tablet formulation (100 mg o.d./b.i.d.; days 1-14) plus gemcitabine (600 mg/m(2)). In an expansion phase, patients with genetically unselected locally advanced or metastatic pancreatic cancer were randomised 2 : 1 to the tolerated olaparib capsule combination dose or gemcitabine alone (1000 mg/m(2)).

RESULTS

Sixty-six patients were treated [dose-escalation phase, n = 44 (tablet cohort, n = 12); dose-expansion phase, n = 22 (olaparib plus gemcitabine, n = 15; gemcitabine alone, n = 7)]. In the dose-escalation phase, four patients (6%) experienced dose-limiting toxicities (raised alanine aminotransferase, n = 2; neutropenia, n = 1; febrile neutropenia, n = 1). Grade ≥3 adverse events were reported in 38/47 patients (81%) treated with olaparib capsules plus gemcitabine; most common were haematological toxicities (55%). Tolerated combinations were olaparib 100 mg b.i.d. capsule (intermittently, days 1-14) plus gemcitabine 600 mg/m(2) and olaparib 100 mg o.d. tablet (intermittently, days 1-14) plus gemcitabine 600 mg/m(2). There were no differences in efficacy observed during the dose-expansion phase.

CONCLUSIONS

Olaparib 100 mg b.i.d. (intermittent dosing; capsules) plus gemcitabine 600 mg/m(2) is tolerated in advanced solid tumour patients, with no unmanageable/unexpected toxicities. Continuous dosing of olaparib or combination with gemcitabine at doses >600 mg/m(2) was not considered to have an acceptable tolerability profile for further study.

CLINICALTRIALSGOV

NCT00515866.