Impact of early response on outcomes in AL amyloidosis following treatment with frontline Bortezomib

The outcomes in systemic AL amyloidosis are dependent on the depth of haematologic response. However, there is limited data on the impact of the speed of response on outcomes. Here we report the impact of speed of response in a cohort of AL patients treated with upfront Bortezomib. Patients seen from February 2010 until August 2019 are included in the present analysis. 1194 & 1133 patients comprised the ITT and 1-month landmark cohorts. In the landmark cohort, 137 (11.5%), 270 (22.6%), 252 (21.1%) and 352 (31.1%) patients had a CR, VGPR, PR and NR at 1-month. Patients with ≥ VGPR at 1-month had significantly better survival (median not reached; at the end of 1, 2, 5,10 years, 87%/92%, 83%/87%, 68%/72% and 63%/58% of patients in CR/VGPR, respectively, were alive) compared to those with a PR (median OS 60 months) or NR (median OS 32 months) (p < 0.005). At 1-month, patients with CR and iFLC < 20 mg/l had a significantly better survival compared to CR and iFLC > 20 mg/l (p = 0.005). Reaching ≥ VGPR at 1-month significantly improved survival in all Mayo disease stages. In conclusion, patients achieving an early deep haematologic response have a significantly superior survival irrespective of cardiac involvement.