Identifying patients at high risk of breast cancer recurrence: strategies to improve patient outcomes

ABBV-176, a PRLR antibody drug conjugate with a potent DNA-damaging PBD cytotoxin and enhanced activity with PARP inhibition

BACKGROUND

Prolactin receptor (PRLR) is an attractive antibody therapeutic target with expression across a broad population of breast cancers. Antibody efficacy, however, may be limited to subtypes with either PRLR overexpression and/or those where estradiol no longer functions as a mitogen and are, therefore, reliant on PRLR signaling for growth. In contrast a potent PRLR antibody-drug conjugate (ADC) may provide improved therapeutic outcomes extending beyond either PRLR overexpressing or estradiol-insensitive breast cancer populations.

METHODS

We derived a novel ADC targeting PRLR, ABBV-176, that delivers a pyrrolobenzodiazepine (PBD) dimer cytotoxin, an emerging class of warheads with enhanced potency and broader anticancer activity than the clinically validated auristatin or maytansine derivatives. This agent was tested in vitro and in vivo cell lines and patient derived xenograft models.

RESULTS

In both in vitro and in vivo assays, ABBV-176 exhibits potent cytotoxicity against multiple cell line and patient-derived xenograft breast tumor models, including triple negative and low PRLR expressing models insensitive to monomethyl auristatin (MMAE) based PRLR ADCs. ABBV-176, which cross links DNA and causes DNA breaks by virtue of its PBD warhead, also demonstrates enhanced anti-tumor activity in several breast cancer models when combined with a poly-ADP ribose polymerase (PARP) inhibitor, a potentiator of DNA damage.

CONCLUSIONS

Collectively the efficacy and safety profile of ABBV-176 suggest it may be an effective therapy across a broad range of breast cancers and other cancer types where PRLR is expressed with the potential to combine with other therapeutics including PARP inhibitors.

Effect of an Artificial Intelligence Clinical Decision Support System on Treatment Decisions for Complex Breast Cancer

PURPOSE

To examine the impact of a clinical decision support system (CDSS) on breast cancer treatment decisions and adherence to National Comprehensive Cancer Center (NCCN) guidelines.

PATIENTS AND METHODS

A cross-sectional observational study was conducted involving 1,977 patients at high risk for recurrent or metastatic breast cancer from the Chinese Society of Clinical Oncology. Ten oncologists provided blinded treatment recommendations for an average of 198 patients before and after viewing therapeutic options offered by the CDSS. Univariable and bivariable analyses of treatment changes were performed, and multivariable logistic regressions were estimated to examine the effects of physician experience (years), patient age, and receptor subtype/TNM stage.

RESULTS

Treatment decisions changed in 105 (5%) of 1,977 patients and were concentrated in those with hormone receptor (HR)-positive disease or stage IV disease in the first-line therapy setting (73% and 58%, respectively). Logistic regressions showed that decision changes were more likely in those with HR-positive cancer (odds ratio [OR], 1.58; P < .05) and less likely in those with stage IIA (OR, 0.29; P < .05) or IIIA cancer (OR, 0.08; P < .01). Reasons cited for changes included consideration of the CDSS therapeutic options (63% of patients), patient factors highlighted by the tool (23%), and the decision logic of the tool (13%). Patient age and oncologist experience were not associated with decision changes. Adherence to NCCN treatment guidelines increased slightly after using the CDSS (0.5%; P = .003).

CONCLUSION

Use of an artificial intelligence-based CDSS had a significant impact on treatment decisions and NCCN guideline adherence in HR-positive breast cancers. Although cases of stage IV disease in the first-line therapy setting were also more likely to be changed, the effect was not statistically significant (P = .22). Additional research on decision impact, patient-physician communication, learning, and clinical outcomes is needed to establish the overall value of the technology.

Breast Cancer Recurrence Risk Assessment: Is Non-Invasive Monitoring an Option?

BACKGROUND

Metastatic breast cancer (MBC) represents a life-threatening disease with a median survival time of 18-24 months that often can only be treated palliatively. The majority of women suffering from MBC are those who had been previously diagnosed with locally advanced disease and subsequently experienced cancer recurrence in the form of metastasis. However, according to guidelines, no systemic follow-up for monitoring purposes is recommended for these women. The purpose of this article is to review current methods of recurrent risk assessment as well as non-invasive monitoring options for women at risk for distant disease relapse and metastasis formation.

METHODS

We used PubMed and national guidelines, such as the National Comprehensive Cancer Network (NCCN), to find recently published studies on breast cancer recurrence risk assessment and systemic monitoring of breast cancer patients through non-invasive means.

RESULTS

The options for recurrence risk assessment of locally invasive breast cancer has improved due to diverse genetic tests, such as Oncotype DX, MammaPrint, the PAM50 (now known as the "Prosigna Test") assay, EndoPredict (EP), and the Breast Cancer Index (BCI), which evaluate a women's risk of relapse according to certain cancer-gene expression patterns. Different promising non-invasive urinary protein-based biomarkers with metastasis surveillance potential that have been identified are MMP-2, MMP-9, NGAL, and ADAM12. In particular, ααCTX, ββCTX, and NTX could help to monitor bone metastasis.

CONCLUSION

In times of improved recurrence risk assessment of women with breast cancer, non-invasive biomarkers are urgently needed as potential monitoring options for women who have an increased risk of recurrence. Urine as a bioliquid of choice provides several advantages - it is non-invasive, can be obtained easily and frequently, and is economical. Promising biomarkers that could help to follow up women with increased recurrence risk have been identified. In order for them to be implemented in clinical usage and national guideline recommendations, further validation in larger independent cohorts will be needed.

Triptorelin: A Review of its Use as an Adjuvant Anticancer Therapy in Early Breast Cancer

A 1-month formulation of the gonadotrophin-releasing hormone agonist (GnRHa) triptorelin (Decapeptyl^®) has been approved in the EU as an adjuvant treatment in combination with tamoxifen or an aromatase inhibitor (AI), of endocrine-responsive, early-stage breast cancer in women at high risk of recurrence who are confirmed as premenopausal after completion of chemotherapy. This indication reflects the results of the 5-year SOFT and TEXT studies, especially SOFT, in which ovarian function suppression (OFS; mainly achieved with triptorelin) added to tamoxifen provided a significant benefit in the overall study population of premenopausal patients only after adjusting for prognostic factors. It emerged that adding OFS to tamoxifen produced more pronounced benefits in terms of disease control and, furthermore, increased overall survival in the cohort of higher-risk patients who had previously received chemotherapy. Also, compared with tamoxifen alone, the combination of OFS plus exemestane produced more pronounced benefits in terms of disease control than OFS plus tamoxifen. OFS induces premature menopause; when combined with either tamoxifen or exemestane, it increased the endocrine symptom burden. Nonetheless, the two combinations had distinct tolerability profiles (e.g. vasomotor symptoms and thromboembolic events were more frequent with OFS plus tamoxifen, whereas musculoskeletal symptoms, decreased libido, osteoporosis and fractures were more frequent with OFS plus exemestane). Thus, the combinations of OFS (with triptorelin) plus either tamoxifen or an AI are valid options for the adjuvant treatment of endocrine-responsive, early-stage breast cancer in women at sufficiently high risk of relapse to warrant receiving chemotherapy and who remain premenopausal thereafter. Individualized weighing of the potential benefits and adverse effects of treatment is required.