Metastatic ER+ Breast Cancer: Mechanisms of Resistance and Future Therapeutic Approaches

Endocrine therapy is the main treatment for hormone receptor-positive (HR+) breast cancer. However, advanced tumors develop resistance to endocrine therapy, rendering it ineffective as the disease progresses. There are several molecular mechanisms of primary and secondary endocrine resistance. Resistance can develop due to either alteration of the estrogen receptor pathway (e.g., ESR1 mutations) or upstream growth factors signaling pathways (e.g., PI3K/Akt/mTOR pathway). Despite progress in the development of molecularly targeted anticancer therapies, the emergence of resistance remains a major limitation and an area of unmet need. In this article, we review the mechanisms of acquired endocrine resistance in HR+ advanced breast cancer and discuss current and future investigational therapeutic approaches.

Ocular toxicities associated with antibody drug conjugates and immunotherapy in oncology: clinical presentation, pathogenesis, and management strategies

INTRODUCTION

The development of molecularly targeted anticancer therapies and immunotherapy continues to revolutionize the treatment of cancer. FDA accelerated approvals of novel targeted therapies allowed for introduction of these agents into the clinic at a rapid rate. On-and off-target ocular toxicities are prevalent treatment-related adverse events of newer therapies including antibody drug conjugates (ADCs) and immunotherapy. Ocular toxicities associated with ADCs and immunotherapy have heterogeneous presentations and pathogenesis requiring unique and often complex monitoring, and management.

AREAS COVERED

In this article, we provide an updated review of treatment-emergent ocular toxicity associated with new and novel oncologic therapies and summarize guidelines and best practice strategies for prevention, monitoring and management. A literature search was performed through PubMed, ClinicalTrials.gov, and FDA website (1 January 2017 to 10 May 2023) to identify relevant information.

EXPERT OPINION

The implementation of a strategy for monitoring, prevention, and management of treatment-related ocular toxicities involves a multi-disciplinary, often cross-center approach. Communication with infusion nursing leadership, clinic staff, and eye care providers is crucial to the successful implementation of eye care plans to prevent and manage ocular toxicity.

Amivantamab-Vmjw: A Novel Treatment for Patients with NSCLC Harboring EGFR Exon 20 Insertion Mutation after Progression on Platinum-Based Chemotherapy

OBJECTIVE

This study is a comprehensive review of the clinical pharmacology, pharmacokinetics, efficacy, safety, and clinical applicability of amivantamab-vmjw for metastatic non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) exon 20 insertion (exon20ins) mutation.

DATA SYNTHESIS

The literature search to identify clinical trials returned only the CHRYSALIS phase 1 study. In a phase I trial, amivantamab-vmjw was associated with an overall response rate (ORR) of 40% (95% CI, 29-51) in the EGFR exon20ins NSCLC patient population (n = 81) after platinum-based chemotherapy. There were 3 complete responses (CRs) and 29 partial responses (PRs). The median duration of response (DOR) was 11.1 months (95% CI, 6.9-not reached; NR). The median progression-free survival (PFS) was 8.3 months (95% CI, 6.5-10.9), and overall survival (OS) was 22.8 months (95% CI, 14.6-NR).

APPLICATION TO CLINICAL PRACTICE

This review summarizes the pharmacology, clinical evidence, and use of amivantamab-vmjw for patients with locally advanced or metastatic NSCLC with EGFR exon20ins mutation.

CONCLUSION

The FDA approval of amivantamab-vmjw, the first bispecific antibody to target the exon20ins mutation, represents an important advancement in the treatment of patients with NSCLC with limited effective treatment options. The initial findings of the CHRYSALIS trial demonstrate an overall tumor response benefit with an acceptable safety profile.

Abstract P4-07-56: Mayo Clinic Enterprise patterns of growth-factor utilization for sacituzumab govitecan (SG)-induced neutropenia among patients with metastatic triple negative breast cancer

Background: SG was approved in 2020 for the treatment of metastatic triple negative breast cancer (TNBC). The most common grade 3/4 adverse event in the ASCENT trial was neutropenia (51.2%) with a 6% incidence of febrile neutropenia. 1 Package insert recommendations do not endorse primary prophylactic growth factor support, rather only initiating if severe neutropenia occurs on treatment.2

Objective: This study retrospectively reviewed the utilization of growth factor support in patients (pts) with metastatic TNBC initiated on SG at each Mayo Clinic Enterprise site.

Methods: We performed a multi-center, retrospective review of all pts with TNBC who received SG from January 2021 to December 2021 at Mayo Clinic sites in Minnesota, Florida, Arizona, and its community-based health system network. Data collected included history of neutropenia with previous cycles of SG resulting in a treatment delay, number of cycles, grade of neutropenia and cycle/day of treatment plan when growth factor added. Pts who received only one dose of SG were excluded. The Fisher’s exact test was utilized to compare the difference in the use of primary prophylaxis between sites.

Results: 67 pts received at least two doses of SG. Within this cohort, 42 pts (63%) received growth factor support during treatment with SG. Growth factor support was most often added during the first two cycles (59.5%). A total of 12 patients initiated growth factor with no history of delays related to neutropenia and without neutropenia at the time of administration. Eleven of these pts had growth factor support added on Cycle 1 as primary prophylaxis. Primary prophylaxis was most common at Mayo Clinic – Rochester compared to the other sites (Table 1), however there was not a statistically significant difference (p=0.27). There were 26 pts (39%) with a treatment delay due to neutropenia while receiving SG, of which 21 (81%) were managed with the addition of growth factor (13 pegfilgrastim, 8 filgrastim). The median number of cycles for all pts was 5 (range: 1-25). Pts who received growth factor were treated with a median of 5 cycles (range: 1-25) and pts who did not receive growth factor were treated with a median of 4 cycles (range: 1-19) (p=0.10).

Conclusions: We observed wide variability in the use of prophylactic growth factor between Mayo Clinic sites with SG. The optimal practice of growth factor use with SG warrants further exploration.

References:

1. Bardia A, Hurvitz SA, Tolaney SM, et al. Sacituzumab govitecan in metastatic triple-negative breast cancer. N Engl J Med. 2021;384(16):1529-1541

2. Immunomedics, Inc. Trodelvy (sacituzumab govitecan-hziy) [package insert]. Foster City, CA: Gilead Sciences; 2020.

Table 1: Grade of neutropenia for patients receiving SG when growth factor initiated

Citation Format: Kaylee Clark, Jamie L. Carroll, Alvaro Moreno-Aspitia, Brenda Ernst, Farah Raheem, Ashley Heil, Beth Boyer, Kristin Mara, Matthew P. Goetz, Roberto A. Leon-Ferre, Karthik V. Giridhar, Jodi Taraba. Mayo Clinic Enterprise patterns of growth-factor utilization for sacituzumab govitecan (SG)-induced neutropenia among patients with metastatic triple negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-56.

New and emerging therapies for the treatment of relapsed/refractory diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common form of aggressive non-Hodgkin lymphoma. Approximately 40% of patients with DLBCL will experience disease relapse or will be refractory to first line chemoimmunotherapy, necessitating second-line salvage therapy. This has historically consisted of platinum-based chemotherapy regimens followed by autologous hematopoietic stem cell transplantation with curative intent for transplant-eligible patients or palliative chemotherapy for transplant-ineligible patients. In recent years there have been several new therapeutic agents approved for the treatment of relapsed/refractory DLBCL, thereby expanding the therapeutic landscape. These agents include polatuzumab vedotin, tafasitamab, loncastuximab tesirine, selinexor, and anti-CD19 chimeric antigen receptor T-cell therapies such as axicabtagene ciloleucel, tisagenlecleucel, and lisocabtagene maraleucel. This review summarizes the pharmacology, efficacy, safety, dosing, and administration of new agents recently approved for the treatment of relapsed/refractory DLBCL.

Abemaciclib: The First FDA-Approved CDK4/6 Inhibitor for the Adjuvant Treatment of HR+ HER2- Early Breast Cancer

OBJECTIVE

To review the new indication of cyclin-dependent kinase (CDK4/6) inhibitor abemaciclib for the adjuvant treatment of hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-), axillary lymph node (LN) positive early breast cancer (EBC) at high risk of recurrence and a Ki-67 ≥20%.

DATA SOURCES

A literature search was performed through PubMed, ClinicalTrials.gov, and Food and Drug Administration (FDA) website (February 1, 2018, to December 23, 2021) to identify relevant information.

STUDY SELECTION AND DATA EXTRACTION

Human and animal studies related to pharmacology, pharmacokinetics, efficacy, and safety of abemaciclib were identified.

DATA SYNTHESIS

Addition of abemaciclib to standard of care endocrine therapy (ET) for patients with high-risk clinicopathologic features and Ki-67 ≥20% demonstrated 30% reduction in the risk of developing invasive disease and distant recurrence. At 15.5 months, abemaciclib + ET demonstrated a significant improvement in invasive disease-free survival (IDFS) vs ET alone (hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.60-0.93, P = 0.01). At 27 months, IDFS benefit was maintained (HR, 0.70; 95% CI, 0.59-0.82, P < 0.0001). Diarrhea occurred in more than 80% of patients in the abemaciclib arm.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review describes the clinical applicability of adjuvant abemaciclib for patients with HR+, HER2- EBC at high risk for recurrence.

CONCLUSION

Adjuvant abemaciclib significantly reduces the risk for early development of invasive disease and distant recurrence in patients with HR+, HER2- node positive EBC. Longer follow-up is needed to determine the impact of adjuvant abemaciclib on late disease recurrence and survival outcomes.

Precision Genomic Practice in Oncology: Pharmacist Role and Experience in an Ambulatory Care Clinic

Recent advancements in molecular testing, the availability of cost-effective technology, and novel approaches to clinical trial design have facilitated the implementation of tumor genome sequencing into standard of care oncology practices. Current models of precision oncology practice include specialized clinics or consultation services based on a molecular tumor board (MTB) approach. MTBs are comprised of interprofessional teams of clinicians and scientists who evaluate tumors at the molecular level to guide patient-specific targeted therapy. The practice of precision oncology utilizing MTB-based models is an emerging approach, transforming precision genomics from a novel concept into clinical practice. This rapid shift in practice from cytotoxic therapy to targeted medicine poses challenges, yet brings exciting opportunities to clinical pharmacists practicing in hematology and oncology. Only a few precision genomics programs in the United States have a strong pharmacy presence with oncology pharmacists serving in leadership roles in research, interpreting genomic sequencing, making treatment recommendations, and facilitating off-label drug procurement. This article describes the experience of the precision medicine clinic at the Indiana University Health Simon Cancer Center, with emphasis on the role of the pharmacist in the precision oncology initiative.