Erin Roesch, MD
The Cleveland Clinic
Peripheral neuropathy is a well-recognized complication of taxane therapy that can impact functioning and quality of life. Dose-reductions are applied in an effort to continue treatment and minimize risk of worsening neuropathy. In a prospective analysis of breast cancer patients receiving weekly paclitaxel, Timmins et al showed neuropathy symptoms affected 85% with severe symptoms in 38%, and about half of the cohort had persistent symptoms up to 12 months post-chemotherapy. Patients who received dose reductions reported worse neuropathy and symptom burden compared to those who received full dose paclitaxel chemotherapy. It is challenging to predict with certainty which patients may experience significant neuropathy, and important to acknowledge individual patients factors such as age and other medical co-morbidities. Additional research is warranted to refine individual risk assessment as well as prevention and management strategies.
The treatment landscape for metastatic HER2-positive breast cancer is evolving at a rapid pace. Margetuximab is a chimeric antibody with similar epitope specificity to trastuzumab, but with an engineered Fc region that enhances immune activation. The phase 3 SOPHIA trial included 536 patients with pretreated HER2-positive advanced breast cancer and demonstrated modest improvement in progression free-survival with margetuximab plus chemotherapy compared to trastuzumab plus chemotherapy (median PFS 5.8 versus 4.9 months; HR 0.76, p=0.03). The introduction of other therapies in this space (tucatinib, trastuzumab deruxtecan, neratinib) provides patients with many options, but simultaneously creates a complex treatment algorithm when it comes to therapy selection. Toxicity profiles and sites of metastases should be taken into consideration when deciding on best therapy for an individual patient.
Given the impressive outcomes seen with endocrine therapy plus CDK 4/6 inhibitors in the advanced HR+/HER2- population, these combinations are being studied in the curative setting. The phase 3 PALLAS study randomized 5,760 patients with stage I-III HR+/HER2- breast cancer to ongoing endocrine therapy with or without palbociclib for 2 years. Data from the second interim analysis of this trial showed similar invasive disease-free survival rates for the two arms (3 years iDFS 88.2% for palbociclib plus endocrine therapy versus 88.5% for endocrine therapy alone; HR 0.93, p=0.51). In contrast, the phase 3 monarchE trial showed improvement in iDFS with abemaciclib for 2 years with ongoing endocrine therapy compared to endocrine therapy alone (2 year iDFS rate of 92.3% versus 89.3%; HR 0.713, p=0.0009). Differences in study populations, mechanism of action of various CDK 4/6 inhibitors, dosing and drug exposure, may possibly impact results. Long-term follow-up and biomarker studies are desired to further delineate the role of CDK 4/6 inhibitors in this setting.
References:
Runowicz CD, Leach CR, Henry NL, Henry KS, Mackey HT, Cowens-Alvarado RL, Cannady RS, Pratt-Chapman ML, Edge SB, Jacobs LA, Hurria A, Marks LB, LaMonte SJ, Warner E, Lyman GH, Ganz PA. American Cancer Society/American Society of Clinical Oncology Breast Cancer Survivorship Care Guideline. J Clin Oncol. 2016;34:611-35.
Ghoreishi Z, Keshavarz S, Asghari Jafarabadi M, Fathifar Z, Goodman KA, Esfahani A. Risk factors for paclitaxel-induced peripheral neuropathy in patients with breast cancer. BMC Cancer. 2018;18:958.
O'Shaughnessy JA, Johnston S, Harbeck N, Toi M, Im Y-H, Reinisch M, Shao Z, Kellokumpu Lehtinen PL, Huang C-S, Tryakin A, Goetz M, Rugo HS, Senkus E, Testa L, Andersson M, Tamura K, Steger GG, Del Mastro L, Cox J, Forrester T, Sherwood S, Li X, Wei R, Martin M, Rastogi P. Primary outcome analysis of invasive disease-free survival for monarchE: abemaciclib combined with adjuvant endocrine therapy for high risk early breast cancer. Presented at: 2020 Virtual San Antonio Breast Cancer Symposium; December 8-11, 2020. Abstract GS1-01.