Abstract PS9-06: Adherence to and patient satisfaction with the combination therapy of exemestane and everolimus in postmenopausal women with HR+ HER2- advanced breast cancer: Results from the IPSOC-mamma study
Authors: Foulon Veerle , Visser Carrie , De Coster Sandra , Kinnaer Lise-Marie , Reynders Ellen , Deblander Anne , Berteloot Patrick , Punie Kevin , Wildiers Hans , Cocquyt Véronique , Denys Hannelore , Awada Ahmad , Strobbe Eric , Gombos Andrea , Spoormans Isabelle , Elzo-Kraemer Ximena , Vulsteke Christof , Borms Marleen , Debruyne Philip , Wynendaele Wim , Neven Patrick 
Published: February 2021

BackgroundEverolimus in combination with exemestane is indicated for the treatment of hormone receptor-positive, HER 2-neg endocrine resistant advanced breast cancer in postmenopausal women. This study investigated treatment adherence, tolerability, satisfaction and efficacy.

MethodsA prospective, non-interventional, non-controlled, multicentric observational study assessed adherence by means of a validated questionnaire (‘Morisky Medication Adherence Scale’) and ‘Medication Event Monitoring System’ (MEMS®) data. The level of adherence was calculated per patient as percentage of days on which the medicine was taken as prescribed during the total treatment period, referred to as ‘unadjusted adherence rate’ (UAR). Second, MEMS® data were adjusted for treatment interruptions according to the CRF and questionnaire data, approved by the treating physician (‘adjusted adherence rate’ (AAR)). Successful adherence was defined as ≥ 95% – ≤ 105%. Validated questionnaires (‘Patient Satisfaction with Cancer Treatment Education’, ‘Cancer Treatment Satisfaction Questionnaire’ (CTSQ) and ‘Functional Assessment of Cancer Therapy – General’ (FACT-G) were used to report patients experience and satisfaction with the treatment and perceived care, questioned at initial visit and after approximately 1, 3, 6 and 12 months. The efficacy was primary analyzed through progression free survival (PFS).

ResultsBetween Dec 2015 and Nov 2017, a total of 58 women (median age 65 yrs) from 7 oncology centers were included after a mean of 34m ± 36.9 (SD) of being diagnosed with stage IV disease; most (62.1%) had ≥3 organs involved and 84.5% had ≥2 prior metastatic treatment lines. The mean follow-up duration was 185.5 ± 100.0 days. The mean UAR for exemestane, everolimus and the combination were 92.9 %, 84.8 % and 81.7 % respectively. For everolimus and the combination therapy these rates differ significantly from the mean AAR, with p &lt; 0.05 (see table 1). For the AAR of the combination therapy, 13.8 % of the patients showed optimal adherence (100 %).

Six patients (10.3%) interrupted their treatment with exemestane with a mean time of treatment pause of 34.3 ± 19.1 days. The treatment with everolimus was interrupted by 36 (62.1%), with a mean interruption time of 24.3 ± 16.5 days, which corresponds with a mean of 19.6 % ± 17.6% of the total follow-up duration. Some patients interrupted their treatment multiple times. The most common side effect was mucositis (n=26 at 1 month, of whom 8 patients grade 3 and 15 patients grade 2)). Six (10.4 %) of the 58 patients stopped treatment with everolimus and exemestane due to side effects. The median PFS was 170 days. With regard to quality of life, patients scored lowest on emotional and functional well-being. However, there were no significant differences measured for the mean FACT-G score between Day0, M1 and M3 (P = 0.273). Also, patients scored overall low on the ‘CTSQ’.

Conclusion Despite close monitoring and preventive measures to overcome side effects, adherence to everolimus and exemestane was rather low. Many patients needed to interrupt the treatment due to side effects; treatment is perceived as intensive. Nevertheless, median PFS is 170 days, even when used late in the therapeutic journey of breast cancer patients.

Table 1. UAR and AAR for Exemestane, Everolimus and the combinationExemestaneEverolimusCombination therapyUAR (%)mean ± SD92.97 ± 13.1784.86 ± 19.4081.74 ± 20.98AAR (%)mean ± SD93.07 ± 13.1491.81 ± 15.0487.55 ± 18.17Significance differenceP-value0.277&lt; 0.001&lt; 0.001

Citation Format: Veerle Foulon, Carrie Visser, Sandra De Coster, Lise-Marie Kinnaer, Ellen Reynders, Anne Deblander, Patrick Berteloot, Kevin Punie, Hans Wildiers, Véronique Cocquyt, Hannelore Denys, Ahmad Awada, Eric Strobbe, Andrea Gombos, Isabelle Spoormans, Ximena Elzo-Kraemer, Christof Vulsteke, Marleen Borms, Philip Debruyne, Wim Wynendaele, Patrick Neven. Adherence to and patient satisfaction with the combination therapy of exemestane and everolimus in postmenopausal women with HR+ HER2- advanced breast cancer: Results from the IPSOC-mamma study [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS9-06.