Efficacy of pembrolizumab and biomarker analysis in patients with WGS-based intermediate to high tumor mutational load: results from the Drug Rediscovery Protocol

PURPOSE

To evaluate efficacy of pembrolizumab across multiple cancer types harboring different levels of Whole-Genome Sequencing (WGS)-based tumor mutational load (TML; total of non-synonymous mutations across the genome) in patients included in the Drug Rediscovery Protocol (NCT02925234).

PATIENTS AND METHODS

Patients with solid, treatment-refractory, microsatellite-stable tumors were enrolled in cohort A: breast cancer TML 140-290, cohort B: tumor-agnostic cohort TML 140-290, and cohort C: tumor-agnostic cohort TML >290. Patients received pembrolizumab 200 mg every three weeks. Primary endpoint was clinical benefit (CB: objective response or stable disease (SD) ≥16 weeks). Pre-treatment tumor biopsies were obtained for WGS and RNA-sequencing.

RESULTS

Seventy-two evaluable patients with 26 different histotypes were enrolled. CB rate was 13% in cohort A (3/24 with partial response (PR)), 21% in cohort B (3/24 with SD, 2/24 with PR), and 42% in cohort C (4/24 with SD, 6/24 with PR). In cohort C, neoantigen burden estimates and expression of inflammation and innate immune biomarkers were significantly associated with CB. Similar associations were not identified in cohort A and B. In cohort A, CB was significantly associated with mutations in the chromatin remodeling gene PBRM1, while in cohort B, CB was significantly associated with expression of MICA/MICB and butyrophilins. CB and clonal TML were not significantly associated.

CONCLUSION

While in cohort A pembrolizumab lacked activity, cohort B and cohort C met the study's primary endpoint. Further research is warranted to refine selection of patients with tumors harboring lower TMLs and may benefit from a focus on innate immunity.

Survival and prognostic factors in oligometastatic breast cancer

BACKGROUND

Guidelines for oligometastatic breast cancer (OMBC) propagate multimodality treatment including polychemotherapy and local ablative treatment (LAT) of all lesions. The aim of this approach is prolonged disease remission, or even cure. Long-term outcomes in OMBC and factors associated with prognosis are largely unknown, due to the rarity of this condition. We report overall survival (OS), event-free survival (EFS), and prognostic factors in a large real-world cohort of patients with OMBC.

METHODS

Patients with breast cancer and 1-3 distant metastatic lesions, treated in the Netherlands Cancer Institute between 1997 and 2020, were identified via text mining of medical files. We collected patient, tumor and treatment characteristics. The Kaplan-Meier method was used to calculate OS and EFS estimates, and Cox regression analyses to assess prognostic factors.

RESULTS

The cohort included 239 patients, of whom 54% had ERpos/HER2neg, 20% HER2pos and 20% triple negative disease. Median follow-up was 88.0 months (95% confidence interval (CI) 82.9-93.1) during which 107 patients died and 139 developed disease progression/recurrence; median OS was 93.0 months (95%CI 66.2-119.8). Factors associated with OS in multivariable analysis were subtype, disease-free interval and radiologic response to first-line systemic therapy; LAT was associated with EFS, but not OS.

CONCLUSIONS

In this large real-world cohort of patients with OMBC, OS and EFS compare favorably to survival in the general MBC population. Radiologic complete response to first-line systemic therapy was associated with favorable OS and EFS, indicating the importance of early optimal systemic therapy. The value of LAT in OMBC requires further study.

[Clinical efficiency research with expensive drugs: doing more with less investment]

Novel innovative drugs have improved disease control, survival and quality of life for many patients. The costs of these drugs, however, are extremely high and threaten the long-term affordability of our health care system. Efficient use of existing drugs can decrease drug expenditure whilst improving patients' quality of life at the same time. Efficiency adjustments should not compromise treatment efficacy and therefore, clinical research on the matter is crucial. In this article, we demonstrate that efficiency research is feasible, as exemplified by the SONIA study. We make the case for a 'revolving fund' in which savings from one study are used to fund a next one. A revolving fund thus stimulates efficiency research and capitalizes research investments in the interest of both patients and society.

Prognostic factors in patients with oligometastatic breast cancer - A systematic review

AIM

Oligometastatic breast cancer (OMBC) is a disease-entity with potential for long-term remission in selected patients. Those with truly limited metastatic load (rather than occult widespread metastatic disease) may benefit from multimodality treatment including local ablative therapy of distant metastases. In this systematic review, we studied factors associated with long-term survival in patients with OMBC.

METHODS

Eligible studies included patients with OMBC who received a combination of local and systemic therapy as multimodal approach and reported overall survival (OS) or progression-free survival (PFS), or both. The Quality in Prognosis Studies (QUIPS) tool was used to assess the quality of each included study. Independent prognostic factors for OS and/or PFS are summarized.

RESULTS

Of 1271 screened abstracts, 317 papers were full-text screened and twenty studies were included. Eleven of twenty studies were classified as acceptable quality. Definition of OMBC varied between studies and mostly incorporated the number and/or location of metastases. The 5-year OS ranged between 30 and 79% and 5-year PFS ranged between 25 and 57%. Twelve studies evaluated prognostic factors for OS and/or PFS in multivariable models. A solitary metastasis, >24 months interval between primary tumor and OMBC, no or limited involved axillary lymph nodes at primary diagnosis, and hormone-receptor positivity were associated with better outcome. HER2-positivity was associated with worse outcome, but only few patients received anti-HER2 therapy.

CONCLUSIONS

OMBC patients with a solitary distant metastasis and >24 months disease-free interval have the best OS and may be optimal candidates to consider a multidisciplinary approach.

Abstract OT1-04-06: Evaluation of cognitive functioning in patients with metastatic breast cancer treated with endocrine or combined therapy

Background: A subset of patients with breast cancer is vulnerable to treatment-related cognitive problems. However, relatively little is known about the cognitive effects of endocrine treatment and the novel cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors in the metastatic setting. Research on possible cognitive effects of these therapies is needed, since cognitive impairment can affect role functioning, independence and quality of life.

Trial design: The current study is a side study of the SONIA (Selecting the optimal position of CDK4/6 inhibitors in hormone-receptor-positive advanced breast cancer) trial: a multicenter, randomized phase III study. The side study is an observational study with nine months of follow-up, comparing two intervention groups (first line non-steroidal aromatase inhibitor + CDK4/6 inhibition vs. single agent non-steroidal aromatase inhibitor) and a reference group of people without a history of cancer. Cognition will be measured at start of treatment (T0) and nine months later (T1), using the Amsterdam Cognition Scan, a validated online neuropsychological test battery that is completed at home without supervision. It includes tests of among others attention, memory, and executive functioning, and two questionnaires on anxiety and depression, and fatigue.

Specific aims: The main objective is to evaluate if there is a difference in cognitive functioning over time in patients with metastatic breast cancer who will undergo first line endocrine treatment + CDK4/6 inhibition vs. endocrine treatment alone.

Eligibility criteria: All patients who participate in the main SONIA study will be eligible for participation: adult women (≥ 18 years of age) with proven diagnosis of hormone receptor-positive, human epidermal growth factor receptor 2 negative adenocarcinoma of the breast with evidence of loco-regional recurrent or metastatic disease not amenable to resection or radiation therapy with curative intent, for whom chemotherapy is not clinically indicated and who have not received any prior systemic anti-cancer therapy for metastatic disease. Participants in the reference group are patients’ female relatives/friends without a history of cancer and without neurological/psychiatric symptoms influencing cognition, who have a sufficient level of Dutch and access to a computer with internet.

Statistical methods: We will use a mixed effects modeling approach to examine changes in cognition from baseline to follow-up between the two intervention groups and the reference group, adjusting for non-ignorable drop-out patterns. The primary endpoint will be the change from baseline to follow-up on the total score of cognition.

Present accrual and target accrual: With an accrual period of 21 months and 9 months of follow-up, inclusion of 260 patients is required. In addition, our already existing reference group (n=157) will be expanded by recruiting participants’ female relatives/friends without a history of cancer.

As of June 2019, 435 patients have enrolled in the main SONIA study. Target accrual is 1050 patients.

Contact information

Study coordinator: Philippe Lee Meeuw Kjoe, Netherlands Cancer Institute, p.lee.meeuw.kjoe@nki.nl

PI: Elsken van der Wall, MD, PhD, UMC Utrecht Cancer Center, E.vanderWall@umcutrecht.nl

PI: Sanne Schagen, PhD, Netherlands Cancer Institute, s.schagen@nki.nl

Citation Format: Philippe Lee Meeuw Kjoe, Elsken van der Wall, Inge Konings, Agnes Jager, Gabe Sonke, Annemiek van Ommen-Nijhof, Sanne Schagen. Evaluation of cognitive functioning in patients with metastatic breast cancer treated with endocrine or combined therapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT1-04-06.