PLoS ONE (Jan 2021)

Efficacy and safety of palbociclib and ribociclib in patients with estrogen and/or progesterone receptor positive, HER2 receptor negative metastatic breast cancer in routine clinical practice.

  • Sushmita Rath,
  • Prahalad Elamarthi,
  • Pallavi Parab,
  • Seema Gulia,
  • Ravindra Nandhana,
  • Smruti Mokal,
  • Yogesh Kembhavi,
  • Prema Perumal,
  • Jyoti Bajpai,
  • Jaya Ghosh,
  • Sudeep Gupta

DOI
https://doi.org/10.1371/journal.pone.0253722
Journal volume & issue
Vol. 16, no. 7
p. e0253722

Abstract

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BackgroundThere is scant data from India on efficacy and safety of palbociclib and ribociclib in routine clinical practice.MethodsThis retrospective, observational, single institution study included patients with estrogen and/or progesterone receptor positive and human epidermal growth factor receptor 2 (HER2) negative metastatic breast cancers, who received palbociclib or ribociclib with any partner endocrine therapy in any line of treatment between January 2016 and June 2019. Data were analyzed for progression-free survival (PFS), overall survival (OS) and toxicity.ResultsThe study included 101 female patients with median age of 57 (IQR 48-62) years, of whom 80 (79.2%) were postmenopausal, 79 (78.2%) received palbociclib or ribociclib in second- or later-line treatment, 59 (58.4%) received fulvestrant and 41 (40.6%) received an aromatase inhibitor. In first-line treatment, at a median follow-up of 21.7 (0.5-41.9) months, median PFS and OS were 21.1 (95%CI 16.36-not estimable) months and not reached, respectively. In second- or later-line setting, at a median follow-up of 17.2 (0.5-43.7) months, median PFS and OS were 5.98 (95%CI 4.96-7.89) months and 20.2 (95%CI 14.1-not estimable) months, respectively. Grade 3-4 neutropenia and febrile neutropenia were seen in 45 (45.0%) and 9 (9.0%) patients, respectively while dose reduction was required in 32 (31.7%) patients. In multivariable Cox regression analysis, first-line setting (HR 0.49, 95%CI 0.25-0.97, p = 0.043) and ECOG performance status 1 (HR 0.43, 95%CI 0.20-0.91, p = 0.028) were significantly associated with PFS while only ECOG PS 1 was significantly associated (HR 0.04, 95%CI 0.008-0.206, p = 0.000) with OS.ConclusionPalbociclib and ribociclib, when used in routine clinical practice in first or subsequent lines of treatment, resulted in efficacy and toxicity outcomes in concordance with those expected from pivotal trials.