Abstract OT3-06-02: A phase Ib trial of xentuzumab and abemaciclib in patients with locally advanced or metastatic solid tumors, including hormone receptor-positive, HER2-negative breast cancer (plus endocrine therapy)

Background: Resistance to endocrine therapy remains an important clinical problem in hormone receptor-positive (HR+), HER2-negative (HER2-) breast cancer (BC), necessitating alternative treatment options. The insulin-like growth factor (IGF) axis and cyclin D-cyclin-dependent kinase (CDK) 4/6-retinoblastoma pathway have been implicated in the pathogenesis and resistance mechanisms of a variety of cancers, including BC. Binding of IGF-I and -II to the IGF receptor results in upregulation of cyclin D1, and subsequent progression through the cell cycle, thus providing rationale for the simultaneous inhibition of IGF-I and -II and CDK4/6. This Phase Ib trial assesses the maximum-tolerated dose (MTD)/recommended phase II dose (RP2D), safety and preliminary efficacy of the IGF-ligand-neutralizing antibody, xentuzumab, in combination with abemaciclib, a selective, small-molecule inhibitor of both CDK4 and 6, in patients (pts) with solid tumors. The trial includes four dose finding cohorts followed by two expansion cohorts. Only those cohorts that will include pts with postmenopausal HR+, HER2- BC will be presented here.

Trial design: In this phase Ib multicenter, non-randomized, open-label, dose escalation trial (BI 1280.18 [NCT03099174]), the key aims in the BC cohorts (Cohorts B–D, F) are to define the MTD or recommended phase 2 dose (RP2D), and to evaluate the preliminary efficacy, safety and tolerability of xentuzumab plus abemaciclib in combination with endocrine therapies. Eligible pts include adults ≥18 yrs (≥20 for Japan), with measurable or evaluable disease, adequate organ function, ECOG PS ≤1, and postmenopausal locally advanced or metastatic HR+, HER2- BC (Cohorts B–D, F). CDK4/6 inhibitor-naïve pts (Cohorts B–D) and pts who have received prior CDK4/6 inhibitors (palbociclib or ribociclib) plus aromatase inhibitors (Cohort F) are included. The MTD/RP2D of xentuzumab plus abemaciclib to be used in Cohorts B–D will be established in pts with solid tumors (Cohort A) who will receive xentuzumab (starting dose 1000mg weekly iv) plus abemaciclib (starting dose 150mg every 12 hours). CDK4/6 inhibitor-naïve pts with BC will receive xentuzumab plus abemaciclib at the RP2D determined in Cohort A in combination with letrozole (2.5mg/day; Cohort B), anastrozole (1mg/day; Cohort C), or fulvestrant (500mg/month; Cohort D). CDK4/6 inhibitor pre-treated pts with BC (Cohort F) will receive xentuzumab plus abemaciclib and fulvestrant at the RP2D determined in Cohort D. Primary endpoints in the BC cohorts are the MTD and/or RP2D of xentuzumab plus abemaciclib in combination with endocrine therapies, and the objective response (OR) in CDK4/6 inhibitor pre-treated pts with advanced BC (Cohort F); disease control (DC), duration of DC, time to OR, duration of OR, and progression-free survival (PFS) in Cohort F are secondary endpoints. Additionally, PK outcomes, safety and tolerability will be assessed in all cohorts. This study will be conducted in the US, Europe and Japan. Pt screening started in May 2017. Target enrolment is ˜88 pts, including ˜56 pts with advanced HR+, HER2- BC, of whom ˜20 had previously been treated with CDK 4/6 inhibitors.

Citation Format: Yee D, Sablin MP, Iwata H, Johnston EL, Bogenrieder T, Serra J, Hua H, Lo Russo P, Prat A. A phase Ib trial of xentuzumab and abemaciclib in patients with locally advanced or metastatic solid tumors, including hormone receptor-positive, HER2-negative breast cancer (plus endocrine therapy) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-06-02.

Comprehensive genomic profiling of head and neck squamous cell carcinoma reveals FGFR1 amplifications and tumour genomic alterations burden as prognostic biomarkers of survival

BACKGROUND

We aimed at identifying deleterious genomic alterations from untreated head and neck squamous cell carcinoma (HNSCC) patients, and assessing their prognostic value.

PATIENTS AND METHODS

We retrieved 122 HNSCC patients who underwent primary surgery. Targeted NGS was used to analyse a panel of 100 genes selected among the most frequently altered genes in HNSCC and potential therapeutic targets. We selected only deleterious (activating or inactivating) single nucleotide variations, and copy number variations for analysis. Univariate and multivariate analyses were performed to assess the prognostic value of altered genes.

RESULTS

A median of 2 (range: 0-10) genomic alterations per sample was observed. Most frequently altered genes involved the cell cycle pathway (TP53 [60%], CCND1 [30%], CDKN2A [25%]), the PI3K/AKT/MTOR pathway (PIK3CA [12%]), tyrosine kinase receptors (EGFR [9%], FGFR1 [5%]) and cell differentiation (FAT1 [7%], NOTCH1 [4%]). TP53 mutations (p = 0.003), CCND1 amplifications (p = 0.04), CDKN2A alterations (p = 0.02) and FGFR1 amplifications (p = 0.003), correlated with shorter overall survival (OS). The number of genomic alterations was significantly higher in the HPV-negative population (p = 0.029) and correlated with a shorter OS (p < 0.0001). Only TP53 mutation and FGFR1 amplification status remained statistically significant in the multivariate analysis.

CONCLUSION

These results suggest that genomic alterations involving the cell cycle (TP53, CCND1, CDKN2A), as well as FGFR1 amplifications and tumour genomic alterations burden are prognostic biomarkers and might be therapeutic targets for patients with HNSCC.

Sequential sorafenib and sunitinib for renal cell carcinoma

PURPOSE

Sorafenib and sunitinib are 2 tyrosine kinase inhibitors that were recently approved for renal cell carcinoma. In many patients sequential administration of the 2 drugs occurs because of the lack of sustained efficacy of the first agent. We determined the efficacy and safety of sequential administration.

MATERIALS AND METHODS

To determine whether cross-resistance occurs between these 2 drugs we analyzed the outcome in 90 consecutive patients with renal cell carcinoma from 4 sites in France who had received the 2 drugs sequentially. All patients received sorafenib followed by sunitinib or vice versa. From 2003 to 2006, 68 patients received sorafenib, while 22 received sunitinib first.

RESULTS

In the sorafenib-sunitinib group median progression-free survival was 26 weeks with sorafenib and 28 with sunitinib. In the sunitinib-sorafenib group median progression-free survival was 22 weeks with sunitinib and 17 with sorafenib. Median overall survival was 135 weeks in the sorafenib-sunitinib group and 82 weeks in the sunitinib-sorafenib group (HR 0.49, 95% CI 0.16 to 0.96, p = 0.04). The average duration of sequential administration was 61 and 49 weeks, respectively, in the sorafenib-sunitinib and sunitinib-sorafenib groups. Each sequence was well tolerated and no increase in grade 3-4 toxicity was observed.

CONCLUSIONS

Overall this retrospective study supports the conclusion of the lack of absolute cross-resistance between tyrosine kinase inhibitors. In this renal cell carcinoma population sorafenib followed by sunitinib was associated with longer survival than sunitinib followed by sorafenib. However, this observation needs further confirmation.