Abstract 1371
Background
Persistence with dmab therapy may impact clinical efficacy in preventing skeletal-related events (SREs), but is undetermined in real-world.
Methods
Single-arm, prospective, observational, non-interventional study in pts with BM from ST (breast, prostate, lung, other) treated with dmab in real-world in Austria, Czech Republic, Hungary, Slovakia, and Bulgaria between 10/2012 and 05/2017. Primary objective: persistence at 24 weeks (wks) (=6 dmab subcutaneous injections; permissible intervals: 4±1 wks). Secondary objectives: persistence at 48 wks, time to non-persistence, calcium (Ca) / vitamin D supplementation, (serious) adverse drug reactions ([S]ADRs) incl. non-adjudicated osteonecrosis of the jaw (ONJ) rate.
Results
598 patients were included, 451 completed 24 wks, 387 completed 48 wks of study, 211 discontinued before 48 wks due to death (n = 80), loss to follow-up (n = 35), informed consent withdrawal (n = 7), dmab discontinuation (n = 56, [S]ADRs [n = 5]), other reasons (n = 28). 10.9% (n = 65) had previous SREs. Persistence with dmab and safety are shown in the table. Persistence at 24/48 wks was 62.6/40.1% overall, 69.5/45.5% for breast, 69.3/46.6% for prostate, 26.1/10.9% for lung, and 40.7/21.1% for other cancers. Median (IQR) duration of dmab exposure was 309 days (168.0, 319.0) and 11 doses (6.0, 12.0). The most frequent reason for non-persistence was the violation of one time window. Overall, analgesics use trended towards weaker analgesics over time, with ∼60% of pts not requiring any analgesics. Serum Ca remained within the normal range of 2.2 to 2.7 mmol/L throughout the study. ∼70% of pts received Ca and vitamin D supplements at baseline, increasing to ∼80% at dose 2 and steadily decreasing thereafter.Table: 1787P
| N = 598 | |
|---|---|
| Persistence, % (95% CI) | |
| At 24 wks | 62.6 (58.4, 66.7) |
| At 48 wks | 40.1 (35.9, 44.4) |
| KM-median (95% CI) time to non-persistence, days | 274.0 (232.0, 316.0) |
| ADRs, n (%) | 61 (10.2) |
| SADRs, n (%) | 8 (1.3) |
| ONJ | 3 (0.7) |
| Incidence of ONJ per pt-year (95% CI) | 0.012 (0.004, 0.029) |
Conclusions
Persistence (Diel, ESMO 2015) and ONJ rate (Stopeck, JCO 2010, Fizazi, Lancet 2011, Henry, JCO 2011) were comparable with previous reports.
Clinical trial identification
Legal entity responsible for the study
Amgen.
Funding
Amgen.
Editorial Acknowledgement
Margit Hemetsberger, Hemetsberger Medical Services, Vienna, Austria.
Disclosure
A.L. Petzer: Speakers honoraria, advisory board: Amgen. D. Niepel, C. Jäger: Employee, stocks: Amgen. R. Greil: Research grants: Celgene, Roche, Merck, Takeda, AstraZeneca, Novartis, Amgen, BMS; Consulting fees: Celgene, Roche, BMS, Takeda, Abbie, AstraZeneca, Novartis. All other authors have declared no conflicts of interest.