Supporting patients with metastatic breast cancer during therapy with cyclin-dependent kinase 4/6 (CDK) inhibitors: A needs assessment

e13054

Background: Combination therapy with cyclin dependent kinase 4 and 6 inhibitors (CDK4/6i: palbociclib, ribociclib and abemaciclib) and endocrine therapy (ET) has markedly improved treatment of hormone receptor positive (HR+), HER2-negative (-) advanced or metastatic breast cancer (MBC) worldwide.However, data is limited on why patients may discontinue CDK4/6i based therapy and how healthcare providers (HCPs) see their role in educating patients (Px) about side effects and supporting compliance. Objective: This study identifies reasons for suboptimal compliance and early discontinuation of CDK4/6i in US HR+ HER2- MBC Px, with a focus on HCPs and Px educational needs related to on-treatment monitoring, side effects and symptom management. Methods: A sequential mixed-methods design was used; 45-minute phone interviews (n=25) informed the development of an online survey (n=193). Both phases included HCPs comprising medical oncologists (ONCs), oncology registered nurses (RNs), nurse practitioners, and physician assistants (NPs/PAs) in community-based settings. Results: Identified areas of improvement for HCPs included: suboptimal competencies were identified: educating Px adequately regarding potential side effects and engaging them to monitor, report, and address them. Among HCPs surveyed, 26%-48% reported suboptimal knowledge of side effects of specific CDK4/6i [Table]. Interviewees noted that educating Px and setting expectations on potential side effects was critical, but 52% of ONCs reported suboptimal skill doing so. A majority of HCPs (68%-91%) expect Px to be able to report all side effects, with half of ONCs considering compliance with medication entirely Pxs’ responsibility, compared with NPs/PAs and RNs at 16-17%. Conclusions: This study identified areas where HCPs can improve their ability to counsel Px and address concerns that may influence a Px’s decision to prematurely discontinue therapy and should be used to inform future professional development initiatives. [Table: see text]

Phase 3 study of tucatinib or placebo in combination with trastuzumab and pertuzumab as maintenance therapy for HER2+ metastatic breast cancer (HER2CLIMB-05, trial in progress)

TPS1108

Background: The current first-line (1L) standard of care (SOC) for human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer (MBC) is trastuzumab (T) plus pertuzumab (P) and a taxane. Despite advances in 1L SOC, most patients (pts) progress during maintenance therapy with T+P. Tucatinib is a tyrosine kinase inhibitor (TKI) approved in combination with T and capecitabine for adults with HER2+ MBC, with and without brain metastases (BM). In HER2CLIMB, the addition of tucatinib significantly prolonged progression-free survival (PFS) and overall survival (OS) in pts with HER2+ MBC and was well tolerated. Adding tucatinib also reduced the risk of disease progression or death in pts with untreated and/or active BM (Murthy et al. 2020, Curigliano et al. 2021). HER2CLIMB-05 investigates whether adding tucatinib to 1L SOC as maintenance therapy will extend PFS while maintaining quality of life (QOL). Methods: HER2CLIMB-05 (NCT05132582) is a phase 3, randomized, double-blind study evaluating tucatinib plus T+P as maintenance therapy for HER2+ MBC. Approximately 650 pts will be enrolled. Eligible pts will have advanced HER2+ disease, no progression on 4–8 cycles of prior 1L SOC, ECOG Performance Status of 0 or 1, and no or asymptomatic BM. Exclusion criteria include prior treatment with anti-HER2 and/or anti-epidermal growth factor receptor TKI (prior SOC for early BC is permitted) or inability to undergo contrast magnetic resonance imaging of the brain. Pts will be randomized 1:1 to receive either tucatinib or placebo twice daily, with T+P once every 21 days. Pts with HR+ disease may receive endocrine therapy. The primary endpoint is investigator-assessed PFS. Secondary endpoints include OS (key endpoint), time to deterioration of health-related QOL, central nervous system PFS, safety, and pharmacokinetic (PK) parameters. PFS and OS will be compared using a 2-sided stratified log-rank test between treatment groups. Time-to-event endpoints will be summarized using the Kaplan–Meier method. PK and safety data will be summarized using descriptive statistics. Enrollment is ongoing in the US, with additional sites planned. Clinical trial information: NCT05132582.

Operational metrics for the ELAINE II study combining a traditional approach with a just-in-time model

1504

Background: Trial recruitment that requires specific actionable mutations based on next-generation sequencing (NGS) is challenging. Barriers can include competing studies, physician study awareness, site proximity, mutation incidence, among other concerns. Methods: This study (NCT04432454) opened clinical sites using two methods during the COVID-19 pandemic. The “Traditional” approach included site selection, IRB and contract approval, and trial activation prior to a patient being identified for enrollment. The second approach used the Tempus “TIME” Trials network that would only open a site after identifying a patient with a mutation of interest and eligible for the trial. Results: The first patient enrolled was on 10/12/20 and the last patient was on 6/24/21. A total of 16 sites (6 Traditional and 10 TIME) participated. All Traditional sites, and none of the TIME sites, were affiliated with major academic institutions. Duration for full CTA execution for Traditional sites averaged 200.5 days (range 142 to 257) and for TIME sites averaged 7.6 days (range 2 to 14). IRB approval time average for Traditional sites was 27.5 days (range 12 to 71) and TIME sites was 3.0 days (range 1 to 12 days). Days from site selection to activation letter for Traditional sites was on average 250.0 days (range 187 to 281) and for TIME sites was 131.6 days (range 22 to 248). Time from study activation to first consent was 33.3 days (range 18 to 58) for Traditional sites and 8.8 days (range 1 to 35) for TIME sites. The first patient on-study was at a TIME site 115 days prior to a Traditional site and the first 7 patients enrolled were at TIME sites. Traditional sites consented 23 and enrolled 16 patients while the TIME sites consented 16 and enrolled 13. The trial enrolled all 29 patients in 8 months with the anticipated enrollment duration being 12 to 18 months. Conclusions: Although the Traditional and TIME programs had different operational models, they both contributed a significant number of patients and reduced the projected enrollment timeline. TIME sites enrolled the initial patients. These results demonstrate that the “Just-in-Time model,” in conjunction with a Traditional model, can reduce projected overall time to enrollment in biomarker-driven studies. [Table: see text]

A011801 (CompassHER2 RD): Postneoadjuvant T-DM1 + tucatinib/placebo in patients with residual HER2-positive invasive breast cancer

TPS595

Background: Patients (pts) with HER2+ early breast cancer (EBC) and invasive residual disease (RD) after neoadjuvant therapy (NAT) have a higher risk of relapse than pts with a pathologic complete response (pCR). Post neoadjuvant T-DM1 has improved invasive disease-free survival (iDFS), but pts with estrogen receptor (ER)-negative or nodal RD have suboptimal outcomes and recurrences in the central nervous system are a problem. More effective treatment strategies are needed. The CompassHER2 trials, EA1181 and A011801, leverage pCR to tailor post neoadjuvant therapy in HER2+ EBC. EA1181 is a NAT de-escalation trial of a taxane, trastuzumab and pertuzumab (THP) in clinical stage II-III HER2+ EBC; pts with a pCR complete HP +/- adjuvant radiation (RT) +/- endocrine therapy (ET). A011801 is an escalation trial for pts with high risk HER2+ RD after NAT, examining addition of the HER2 selective tyrosine kinase inhibitor (TKI) tucatinib to adjuvant T-DM1. Methods: Eligibility and Intervention: Pts. with high-risk HER2+ RD (e.g. ER-,node-positive, or both) after a predefined course of neoadjuvant HER2-directed treatment are randomized 1:1 to adjuvant T-DM1+ placebo (pb), vs. T-DM1 and tucatinib with adjuvant RT +/- ET. Eligibility criteria include completion of ≥ 6 cycles of NAT, including ≥ 9 weeks of T and H +/- P. All chemotherapy (CT) must be completed preoperatively unless participating in EA1181 (̃15-30% enrollees); these pts must receive postoperative CT to complete ≥ 6 cycles prior to enrollment on A011801. Pts who received prior HER2-targeted TKIs or antibody-drug conjugates are ineligible. Objectives: The primary objective is to determine if iDFS is higher with addition of T-DM1 to tucatinib in pts with HER2+ EBC with RD after NAT; secondary endpoints include overall survival, breast cancer free survival, distant recurrence-free survival, brain metastases-free survival and disease-free survival. Correlative objectives include the association of i) tumor infiltrating lymphocyte (TILs) levels in the primary tumor and RD with iDFS, ii) TILs with tucatinib benefit, iii) iDFS and circulating tumor cells (CTC) at serial timepoints and iv) the magnitude of benefit of tucatinib (iDFS) in pts with/without detectable pretreatment CTCs. Quality of life and pharmacokinetic endpoints will also be evaluated. Statistics: A011801 is a prospective, double-blind, randomized, phase III superiority trial; stratified by i) receipt of postoperative CT (Y/N), ii) hormone receptor-status (+/-),and iii) pathologic lymph node status (+/-). The study targets an absolute difference of 5% in iDFS (control vs. experimental arm 82% & 87%, HR = 0.7), with a two-sided alpha of 0.05 and power of 80%. The sample size is 981; target accrual = 1031 pts; activation and completion dates are 01/6/21 and ̃ 01/2028. Support: U10CA180821, U10CA180882; Seagen Inc; ClinicalTrials.gov Identifier: NCT04457596 Clinical trial information: NCT04457596.

Phase I/II trial of pembrolizumab in combination with binimetinib in unresectable locally advanced or metastatic triple negative breast cancer

TPS17

Background: Emerging studies suggest that breast cancer, particularly triple negative breast cancer (TNBC), may be sensitive to immunotherapy. However, the response rate of single agent immune checkpoint blockade agent in TNBC is rather low. Previous genomic study in residual tumor after neoadjuvant chemotherapy showed inverse correlations between MEK activation signature and the amount of tumor infiltrating lymphocytes (TILs) in residual disease samples as well as poor outcome. Preclinical study also showed that the combination of MEK inhibitor and anti-PD-L1 antibody in mouse model can eradicate TNBC tumors. Methods: This is a single arm, Phase I/II trial of Pembrolizumab (P) in combination with Binimetinib (B) in patients with unresectable locally advanced or metastatic TNBC. This trial is currently opened for accrual at Mayo Clinic in Florida and Minnesota. Patients with TNBC defined as ER ≤ 10% and PR ≤ 10% who received ≤ 3 prior lines with measurable disease will be enrolled. The primary objective of the Phase I part is to determine the maximum tolerated dose of B in combination with P and for the Phase II part is objective response rate (ORR) by RECIST criteria. The secondary endpoints include ORR by irRECIST, progression free survival, and overall survival. The total sample size is 15-38 patients with 6-12 patients in Phase I with 2 dose levels and 9-26 patients in Phase II. Simon’s Two-Stage Optimal Design is used to test the null hypothesis that this two-drug combination has an ORR of at most 15% vs. the alternative hypothesis that it has an ORR of at least 35%. Patients will receive single agent B for 2 weeks prior to starting P. A mandatory biopsy will be performed before starting B and an optional biopsy will be performed after 2 weeks of B. Tumor tissue will be evaluated for the amount and phenotypes of TILs, PD-L1 expression, and gene expression analysis using PanCancer Immune Profiling Panel, and PDJ amplification. Peripheral blood will be evaluated for circulating immunoregulatory cells, cytokine profiling, circulating tumor cells (CTCs), as well as p-ERK and PD-L1 expression on CTCs. Clinical trial information: NCT03106415.