Multi-hit TP53 confers the poorest survival in multiple myeloma in the era of novel therapies

Multiple myeloma (MM) with high-risk (HR) genetic abnormalities has poor prognosis, despite the use of novel therapeutic agents. However, the individual contribution of specific HR genetic abnormalities or their co-occurrence to poor outcomes, especially in the era of novel agents, remains unclear. This study evaluated the impact of multi-hit TP53 (del(17p) and TP53 mutation or ≥ 2 TP53 mutations) compared with other HR abnormalities on progression-free survival (PFS), overall survival (OS) and blood signature in a real-world cohort of 204 patients with MM treated with novel agents (median follow-up 28 months). Patients with multi-hit TP53 (10.4%) had the shortest PFS and OS compared with those with single HR abnormalities (p ≤ 0.011) or with co-occurrence of ≥ 2 other HR abnormalities (p ≤ 0.002), regardless of therapy line. The relative risk of early progression in patients with multi-hit TP53 was almost three times higher than that of patients with other HR abnormalities. The prevalence of TP53 alterations increased in later disease stages: multi-hit TP53 was detected in 7.6% of patients with ≤ 1 prior therapy line and in 36.4% of patients with ≥ 2 prior lines. Patients with multi-hit TP53 also differed in blood signature, particularly in counts of white blood cells, lymphocytes, serum creatinine and β2-microglobulin levels compared with those with other HR abnormalities. In conclusion, multi-hit TP53 is associated with the poorest survival among all HR subgroups in MM. Considering that TP53 alterations accumulate during MM progression and are associated with drug resistance even in the context of novel therapies, our study further emphasizes the need for routine evaluation of both del(17p) and TP53 mutations. Patients with multi-hit TP53 should be prioritized for inclusion in trials of novel therapeutic strategies.