P978: EVOLVING PATTERNS IN MULTIPLE MYELOMA TREATMENT ATTRITION RATES AND PROGRESSION THROUGH LINES OF THERAPY WITH MODERN CHEMOTHERAPY OPTIONS

Abstract Topic: 14. Myeloma and other monoclonal gammopathies - Clinical

Background: Treatment patterns in multiple myeloma (MM) have changed rapidly over the past decade. The introduction of several novel therapies allowed the provision of new lines of treatment. Nevertheless, it is recognised that there is a significant attrition rate with each line of treatment such that, in one major study, only 15% of patients were able to reach to fourth line. This lends to the notion of using the best therapy first. The improvements in the treatment options, selection criteria and supportive care gives a perception that those reported attrition rates may not be as dramatic as they have been previously, and most patients are able to progress through several lines of therapy.

Aims: We sought to examine the impact of changing patterns of myeloma therapy on the attrition rates and the progression of MM patients through lines of therapy. We also assessed the progression-free survival (PFS) of various lines of therapy and the overall survival (OS) of the whole cohort of patients.

Methods: Medical records of symptomatic MM patients diagnosed at our centre between 2015 and 2022 were analysed for the lines of therapy, treatment response, progression and mortality. In addition, basic demographics data, cytogenetics and baseline disease characteristics were collected. Progression was assessed based on IMWG criteria.

Results: Three hundred and seventy symptomatic MM patients were eligible for 1 st line treatment with a median age of diagnosis of 72 years. 109 patients were transplant eligible. The median PFS after 1 st line treatment was 17 months (48 months in the transplant eligible vs 9 months otherwise). The median PFS for patients after second- and third-line treatment was similar at 9 and 10 months respectively but dropped to 5 months after fourth-line therapy. The median OS (overall survival) was significantly better in those who have had a transplant at 1 st line (NR vs 50 month) and was better in under- than over 65 years (NR vs 57 months).

Two hundred and fifty-four patients progressed after 1 st line and 215 (86%) of those were able to proceed to second line of therapy (attrition rate of 14%). 116 out of 150 and 71 out of 93 proceeded to third- and fourth line giving attrition rates of 22.7% and 23.7% respectively.

The most common first line treatment in transplant eligible patients were VTD (bortezomib, thalidomide, dexamethasone) and VMP (bortezomib, melphalan, prednisolone) for transplant ineligible patients, while lenalidomide-based combinations featured heavily in second line.

Summary/Conclusion

The data from our centre showed that most MM patients who progressed were able to proceed to subsequent lines of treatment with lower than previously reported attrition rates. This may point to improvements in the selection criteria, supportive care and treatment options. The better PFS data for first line treatments would still affirm the notion of using the best treatment first. Our data would still suggest the benefit of upfront autologous stem cell transplant with an OS benefit.

Keywords: Autologous bone marrow transplant, Outcome measurement