Palbociclib in hormone positive metastatic breast cancer: A real world multicenter Indian experience.

Abstract

e13057 Background: Palbociclib, a selective CDK4/6 inhibitor, in combination with hormonal therapy has become the standard of care in the treatment of hormonal positive (HR+) metastatic breast cancer (MBC). There is limited efficacy and safety data in Indian patients. Methods: This is a multicenter retrospective study of real world experience of patients with HR+, Her 2 neu negative MBC who received Palbociclib in 5 centers of south India between Oct 2016 and Aug 2019. Endpoints were overall response rate (ORR), progression free survival (PFS) and toxicity. Results: 133 patients received Palbociclib; 83 (62.4%) in the first line setting (hormone naïve MBC) and 50 (37.6%) in the second line (MBC progressed on at least one line of hormonal therapy). Median age was 56 years (range 48-76). All patients started with 125mg/day. In the 83 first line patients, 46 (55.4%) had denovo MBC, 37 (44.6%) had post-adjuvant relapse. 38 (45.8%) had bone only and 45 (54.2%) had visceral metastases. Letrozole was the companion drug in 76%, Fulvestrant in 18%, Exemestane in 6%. 5 (6%) patients achieved complete response (CR), 54 (65%) partial response (PR), 12 (14.5%) stable disease (SD) and 12 (14.5%) had progressive disease (PD). ORR was 71%. At a median followup of 18 months, the median PFS was not reached (maximum ongoing followup 38 months). The median PFS in the denovo metastatic disease versus relapsed disease was not reached versus 18 months (p = 0.021). The median PFS was significantly better in bone only versus visceral metastases (not reached versus 28 months, p = 0.007). In the 50 second line patients, 15 (30%) had bone only and 35 (70%) had visceral metastases. Companion drug was Fulvestrant in 64%, Letrozole in 20%, Exemestane in 16%. 60% received prior chemotherapy. Best response was CR 3 (6%), PR 23 (46%), SD 4 (8%), PD 17 (34%), not assessed 3 (6%). ORR was 52%. The median PFS was 14 months. PFS in bone only versus visceral disease was 14 months versus 13 months (p = 0.382). Neutropenia was present in 75.2%, thrombocytopenia in 19.5%, anaemia in 18%. Neutropenia was grade 1 in 26%, grade 2 in 51%, grade 3 in 23%; with no febrile neutropenia. 30% had dose delays and 8.2% had dose reduction. Conclusions: Palbociclib has resulted in similar efficacy and safety in Indian patients as the PALOMA trials. Neutropenia was the commonest side effect, which was uncomplicated and easily managed with dose delays. Using CDK4/6 inhibitors with hormonal therapy has become the standard of care in HR+ MBC Indian patients.

Outcome in patients of hormone receptor (HR) positive (Her 2) negative metastatic breast cancer treated with palbociclib – A real-world experience

“…[5] The PFS and toxicity analysis results are consistent with other reports of routine clinical practice, that is, real-world evidence from India and other countries and the global clinical trials. [6][7][8][9][10][11][12][13][14][15][16][17] The observed OS is lower than reported in real-world studies and clinical trials. Our analysis suggests that patients who were less heavily pre-treated had better outcomes.…”

“…The safety profile of palbociclib was consistent with that seen in clinical practice and trials in India and other countries. [6,[10][11][12]15,16] The major limitation of our study is its retrospective nature as that introduces a potential bias in patient selection, also it being a single-institutional single-arm study with a small sample size.…”