**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Maximilian J. Steinhardt
Interdisciplinary Amyloidosis Center of Northern Bavaria, University Hospital Würzburg, Germany
Medizinische Klinik und Poliklinik II, Universitätsklinikum Würzburg, Würzburg, Germany

**Main Body of the Abstract**
AL amyloidosis (AL) typically originates from plasma cell (PC) clones producing amyloidogenic light chains. These are distinct in proliferation, paraprotein production, and cytogenetics. Differences in PC biology affect prognosis and may imply different therapeutic strategies.
We retrospectively studied 378 patients with biopsy-proven systemic PC-derived AL from Jan2006 to Dec2023 that received HD or triplet /quadruplet therapy. HD-uneligible and myeloma patients were excluded.
54 patients received high-dose (HD) melphalan (median 140 mg/m²), 52 were treated without HD. They were evenly distributed for cardiac involvement (53%, median Mayo stage II), BMPC (13/11%), lambda phenotype (80/85%), and t(11;14) (53%). An R2ISS high-risk phenotype was prevalent in 23/30%. Serologic response (69/75% ≥VGPR) and cardiac response (32/27% ≥VGPR) were similar. No patients were transplanted due to progression.
Median PFS/OS were not different (p=0.7/0.6) after a median follow-up of 47 months. Patients with HR had poorer PFS (134/60 months, p=0.02). BMPC>10% predicted PFS (84/45 months, p=0.05). R2-ISS and dFLC did not differentiate PFS/OS.
Patients without HR/BMPC>10% benefited from intensive therapy: patients with HD had better PFS (124/56 months, p=0.04). Quadruplets provided longer PFS (nr/56 months, p=0.03). Patients with HR had poorer PFS (28/123 months, p=0.04) but a trend to benefit from HD (PFS 30/13 months, p=0.09). Quadruplets did not overcome HR (PFS 18/31 months, p=0.02).
Overall, in a well-defined cohort, patients without HR/BMPC>10% showed significant PFS benefit from both HD and quadruplets.
In patients with HR, only HD was able to ameliorate the poor prognosis, suggesting an important role for myeloma-derived cytogenetics in AL therapy planning.



Plasma cell characteristics predict benefit from intensified therapy in AL amyloidosis OA18 (#235)

We invite you to attend the XIX International Symposium on Amyloidosis to be held in Rochester, MN.

This symposium is organized as a hybrid meeting (with the focus on in-person) held from Sunday, May 26 through Thursday, May 30, 2024.

Together with the ISA Board and members of Mayo Clinic, a very attractive scientific hybrid program is being planned. The program will cover a variety of types of systemic amyloidosis: ATTR (hereditary and wild-type), AL (light-chain), AA and less frequent forms. There will be key lectures, specific symposia including those company sponsored, oral presentations and poster sessions of accepted abstracts.

COURSE DESCRIPTION
This program will provide a comprehensive review of state-of-the-art education in systemic amyloidosis: basic science, pathophysiology, diagnosis, current and emerging treatments. Scientific presentations will include competitive oral and poster abstracts. The rapid evolution of scientific discovery and expanding treatment options has created tremendous interest in the field and this meeting will fill and important gap in educating scientists and clinicians.