ABSTRACT
Background: Aromatase inhibitors (AI) in combination with a CDK 4/6 inhibitor have been established as the standard first line treatment of non AI-resistant hormone receptor-positive (HR+) HER2-metastatic breast cancer (mBC) patients (pts). ESR1 mutations are known drivers of resistance to AIs in the metastatic setting but their actionability remains unknown. The phase 3 PADA-1 trial aimed both at refining the global safety of palbociclib combined to any AI as first line treatment of HR+ HER2-mBC pts, and at evaluating the clinical benefit associated with a switch to fulvestrant-palbociclib upon detection of a rising ESR1 mutation in blood (bESR1mut). Methods: PADA-1 (NCT03079011), a multicenter, randomized, open-label, phase 3 trial, enrolled HR+ HER2-mBC pts with no prior therapy for mBC, in the absence of AI-resistance. In the first step, pts received a combination of any AI and palbociclib at standard recommended doses and underwent centralized bESR1mut screening every two months. In the second step, bESR1mut+ pts with no S clinical/imaging concomitant disease progression were randomized between continuing the same therapy (standard arm) or switching to fulvestrant-palbociclib (experimental arm). The third step consisted in an optional cross-over after tumor progression for patients randomized in the standard arm. PADA-1 co-primary endpoints were global safety of the combination of palbociclib + endocrine therapy in the whole population of patients, throughout the study, with focus on hematological toxicities;and PFS in the second step. We present here the results of the global safety co-primary endpoint. Results: From 3/2017 to 01/2019, 1017 pts were accrued in 83 sites. As per 05/2021, 272 pts were still in step 1, 35 in step 2, and 8 in step 3. The overall follow-up was 33.7 months. 232 pts have deceased. 333 SAEs have been reported, including 21 grade 5, 35 grade 4, 183 grade 3, 53 grade 2, 26 grade 1 and 15 unknown grade. Among the grade 5 cases, 2 have been declared as potentially related to the underlying treatment (Death of unknown cause, pulmonary embolism). No pt died of SARS-CoV2 infection. The main hematological toxicities encountered, as well as selected non-hematological events are described in Table 1. Permanent discontinuation of the treatment due to toxicity occurred in 39 pts/1017 (3.8%). Palbociclib dose decreases occurred in 419 (41.2%) pts. Conclusion: By the number of included patients, PADA-1 is the largest prospective trial with 1st line AI and palbociclib. Data confirm the favorable safety profile of palbociclib when combined to any AI +/-switch to fulvestrant. Hematological toxicity appears limited and is mostly restricted to non-clinically significant neutropenia. Permanent discontinuation was exceptional. Detailed per-step analyses will be presented.
ABSTRACT
Treatment of patients with cancer in hospitals or clinics is resource-intensive and imposes a burden on patients. 'Flexible care' is a term that can be used to describe treatment administered outside the oncology ward, oncological outpatient clinic or office-based oncologist setting. Programmes that reduce travel burden by bringing cancer treatment to the patient's home, workplace or closer to the patient's home, in the form of satellite clinics or mobile cancer units, expand treatment capacity and are well received. Clinical trial data show that, compared with intravenous administration, subcutaneous (s.c.) administration of trastuzumab is preferred by patients with breast cancer (BC), saves healthcare professionals' (HCPs) time, reduces drug preparation and administration time and reduces direct and indirect costs. As such, s.c. trastuzumab is well suited to flexible care. The results of a Belgian study (BELIS) show that home administration of s.c. trastuzumab is feasible and preferred by patients with BC. Numerous programmes and pilot studies in Europe show that s.c. trastuzumab can be administered effectively in the patient's home, in primary care settings or local hospitals. Such programmes require planning, training, careful patient selection and technology to link patients, caregivers and specialists in oncology clinics. Once these elements are in place, flexible care offers patients with BC a choice of how treatment may be delivered and lead to improved quality of life, while reducing pressure on HCPs and hospitals. The concept of flexible care is particularly relevant amid the COVID-19 pandemic where guidelines have been developed encouraging remote care.