**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.**
Nirija Ranjit Anderson, Princess Alexandra Hospital, Brisbane, Queensland, Australia

**Main Body of the Abstract**
Aim:
To determine the impact of hematological response after 2 months of bortezomib-based therapy on subsequent best hematological and organ responses, and survival.
Methods:
Retrospective review was performed on patients with newly diagnosed AL amyloidosis commenced on a bortezomib-based regimen. Haematological response after 2 months of treatment on subsequent best haematological and organ response was assessed using Fisher’s exact test. Overall survival was assessed by landmark analysis using log-rank or Cox regression analysis. Organ involvement and response criteria were as per the International Society of Amyloidosis definitions.
Results: 
190 patients were assessed; patient characteristics and outcomes were as per figure 1. Failure to achieve PR by 2 months was associated with a low chance of achieving deeper responses, with only 16% going on to achieve VGPR or better (p<0.001) and predicted a low likelihood of cardiac (6% vs 56%, p=0.001) and renal (30% vs 46%, p=0.097) response. Failure to achieve PR after 2 months predicted worse OS (median 31 vs 88 months, p=0.001).
In patients with Mayo Stage 3A/3B cardiac disease, ≤VGPR by 2 months was associated with reduced cardiac response (25% vs 61%, p<0.001) and worse overall survival (median OS 30 vs 72 months, p<0.001).
Conclusion: 
Failure to achieve haematological PR or better after 2 months of bortezomib-based therapy indicates therapeutic failure and need for salvage therapy. Failure to achieve ≥VGPR by 2 months in patients with advanced cardiac disease (stage 3A/3B) predicts poor cardiac response and survival, defining a suboptimal response.



**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.**
Nirija Ranjit Anderson, Princess Alexandra Hospital, Brisbane, Queensland, Australia

**Main Body of the Abstract**
**Aim:**
To determine the impact of hematological response after 2 months of bortezomib-based therapy on subsequent best hematological and organ responses, and survival.
**Methods:**
Retrospective review was performed on patients with newly diagnosed AL amyloidosis commenced on a bortezomib-based regimen. Haematological response after 2 months of treatment on subsequent best haematological and organ response was assessed using Fisher’s exact test. Overall survival was assessed by landmark analysis using log-rank or Cox regression analysis. Organ involvement and response criteria were as per the International Society of Amyloidosis definitions.
**Results:** 
190 patients were assessed; patient characteristics and outcomes were as per figure 1. Failure to achieve PR by 2 months was associated with a low chance of achieving deeper responses, with only 16% going on to achieve VGPR or better (p<0.001) and predicted a low likelihood of cardiac (6% vs 56%, p=0.001) and renal (30% vs 46%, p=0.097) response. Failure to achieve PR after 2 months predicted worse OS (median 31 vs 88 months, p=0.001).
In patients with Mayo Stage 3A/3B cardiac disease, ≤VGPR by 2 months was associated with reduced cardiac response (25% vs 61%, p<0.001) and worse overall survival (median OS 30 vs 72 months, p<0.001).
**Conclusion:** 
Failure to achieve haematological PR or better after 2 months of bortezomib-based therapy indicates therapeutic failure and need for salvage therapy. Failure to achieve ≥VGPR by 2 months in patients with advanced cardiac disease (stage 3A/3B) predicts poor cardiac response and survival, defining a suboptimal response.



Identifying Early Suboptimal Hematological Response in Patients with AL Amyloidosis Treated with Bortezomib-based Therapy. PA115 (#186)

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.