Abstract 135P
Background
Abemaciclib in combination with endocrine therapy is approved for adjuvant treatment of adult patients (pts) with HR+/HER2-, node-positive, early breast cancer (EBC) at high risk of recurrence. Anecdotal insights indicate providers may initiate abemaciclib at a lower dose (LD) than the approved 150mg twice daily (BID) to aid tolerability with the aim to increase to the approved dose. This real-world (rw) study describes demographic and clinical characteristics, dosing patterns and incidence of pre-specified adverse events (AEs) in pts with EBC who initiated abemaciclib at a LD.
Methods
This study used the nationwide Flatiron Health electronic health records-derived de-identified database. Pts initiating abemaciclib Oct 2021-Nov 2022 were included. All results were summarized descriptively. Additional analyses were conducted to compare characteristics of pts initiating <150mg BID vs. 150mg BID.
Results
Among 453 pts, 65 initiated abemaciclib at <150mg BID (median follow-up time 7.1 months). Median age was 56 years, 33.8% had stage III disease, 49.2% had ECOG score of 0 and median Charlson comorbidity score was 0. Abemaciclib was frequently combined with aromatase inhibitors (92.3%). The most common starting doses were 100mg BID (56.9%) and 150mg once daily (QD) (24.6%), the time to first dose increase was 71 and 15 days, respectively. At first dose modification, 32.3% pts increased dose to 150mg BID (Table). Common rwAEs were diarrhea (58.5%), fatigue (52.3%), and nausea/vomiting (40.0%). In comparison to pts initiating at 150mg BID (n=388), pts started on a LD were more likely to be aged ≥75 (4.9% vs. 13.8%, p = 0.022).
Conclusions
In the rw, pts with HR+/HER2- EBC initiating abemaciclib at < 150mg BID were started on different doses and titration intervals. One-third of pts managed to increase dose to 150mg BID. rwAEs were generally consistent with clinical trial results. Table: 135P
Dose modification in patients starting abemaciclib <150mg BID by starting doses
| Overall cohort (n=65) | 100mg BID (n=37) | 150mg QD (n=16) | Other dose* (n=12) | |
| No dose modification, n (%) | 28 (43.1) | 23 (62.2) | 1 (6.2) | 4 (33.3) |
| First dose modification, n (%) | 37 (56.9) | 14 (37.8) | 15 (93.8) | 8 (66.7) |
| Dose decrease | 7 | 6 | 1 | - |
| Dose increase | 30 | 8 | 14 | 8 |
| Increased to 150mg BID | 21 | 8 | 13 | - |
*100mg QD (n=5), 50mg BID (n=6), 50mg QD (n=1) Abbreviations: BID, twice daily; QD, once daily
Legal entity responsible for the study
Eli Lilly and Company.
Funding
Eli Lilly and Company.
Disclosure
L.M. Spring: Financial Interests, Institutional, Advisory Board: Novartis, Daiichi Sankyo, AstraZeneca, Eli Lilly, Precede, Seagen; Financial Interests, Institutional, Sponsor/Funding: Merck, Genentech, Gilead, Eli Lilly. W.G. Gathirua-Mwangi, Z.L. Cui, E. Brechtelsbauer, S. Rybowski, S. Kim: Financial Interests, Personal, Full or part-time Employment: Eli Lilly and Company; Financial Interests, Personal, Stocks/Shares: Eli Lilly and Company. M. Richey: Financial Interests, Personal, Stocks/Shares: Roche. S. Whipple: Financial Interests, Personal, Full or part-time Employment: Eli Lilly and Company; Financial Interests, Personal, Stocks/Shares, Stocks through Employer: Eli Lilly and Company. J. Wang: Financial Interests, Personal, Stocks/Shares: Roche. A.M. Liepa: Financial Interests, Personal, Full or part-time Employment: Eli Lilly and Company; Financial Interests, Personal, Stocks/Shares: Eli Lilly and Company; Financial Interests, Personal, Writing Engagements, Medical writing: Eli Lilly and Company. A. Levoir, M. Moreira, R. Volodarsky: Financial Interests, Personal, Full or part-time Employment: Eli Lilly and Company. H. Soliman: Financial Interests, Personal, Speaker’s Bureau, Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: Merck; Financial Interests, Personal, Other, Consulting fees: Puma, Novartis, Eli Lilly, AstraZeneca, Sermonix.