Prognostic Factors for Early (<2 years) and Late (>5 years) Relapse in Multiple Myeloma- Pivotal Role of Cytogenetic Changes

Background

Multiple myeloma (MM) is an incurable disease, and its prognosis is largely influenced by clinicopathological features, response to therapy, and relapse characteristics. Despite novel agents and the attempts to individualize treatment strategies based on baseline risk stratification, significant variations in progression-free survivals (PFS) and overall survivals (OS) are observed between patients. We examined the outcomes of MM patients stratified according to timing of first relapse into early (<2 years) and late (>5 years).

Methods

We retrospectively assessed 1441 MM patients seen at Mayo Clinic between 2003 and 2018. Patients were 18 years or older and had at least one disease relapse that required an additional line of treatment. The study cohort was divided into three groups based on time of first relapse: early relapse (<2 years from diagnosis), relapse between 2 to 5 years from diagnosis, and late relapse (>5 years from diagnosis). The independent predictors of early/late relapse were identified using a forward stepwise multivariate logistic regression. Odds ratios in multivariate models were adjusted for age and sex.

Results

Early relapse has been recognized in 758 patients (52.6%), relapse between 2-5 years in 561 patients (38.9%), late relapse in 122 patients (8.5%). Six patients had a PFS >10 years. In comparison to patients with late relapse, patients with early relapse were older (median 63 vs 61 years, p=0.04), more frequently ISS stage III (40% vs 20%, p<0.001) had higher bone marrow plasma cell infiltration (median 60% vs 40%, p<0.001), and were more likely to have high-risk (HR) FISH (defined as translocation t[4;14], t[14;16], t[14;20], deletion 17p or p53 mutation; 28% vs 11%, p<0.001). At diagnosis, early relapse group more often presented with anemia (35% vs 21%, p=0.004), hypercalcemia (15% vs 5%, p<0.001), renal insufficiency (19% vs 5%, p<0.001) and higher serum beta-2-microglobulin (median 4.4 vs 3.4 mg/l, p<0.001).

In terms of first line treatment, novel agents use was higher in early relapse group in comparison to late relapse group (82% vs 72%, p=0.007). Early relapse patients more often received PI-based therapy (30% vs 10%, p<0.001) or PI+IMID-based therapy (22% vs 12%, p=0.01), whereas late relapse patients received more often IMID-based therapy (63% vs 37%, p<0.001). No differences in the maintenance therapy were observed. Early relapse patients were less frequently treated with upfront autologous stem cell transplantation (ASCT, 35% vs 60%, p<0.001). Progression on active treatment/maintenance was observed more often in the early relapse group (55% vs 18%, p<0.001).

On multivariable logistic regression model early relapse (vs all remaining patients) was predicted by HR cytogenetic features (odds ratio [OR] 3.06, 95% confidence interval [CI] 1.71-5.46, p<0.001), non-IgG isotype disease (OR 2.17, 95% CI 1.33-3.54, p=0.02), a non-ASCT pathway (OR 2.78, 95% CI 1.71-4.52, p<0.01), and by achieving less than a very good partial remission (VGPR; OR 3.23, 95% CI 1.96-5.35, p<0.01).

The only factor associated with decreased chances of late relapse (vs all remaining patients) on multivariate logistic regression model was the presence of HR FISH features (OR 0.18, 95% CI 0.04-0.82, p=0.03).

Median PFS from first relapse for the whole population was 13.9 months (95% CI 12.9-15.1), median OS from first relapse - 44.6 months (95% CI 41.7-183.0). Early relapse group exhibited worse median PFS and OS from first relapse (median PFS 9.1 months; median OS 26.6 months) than patients who relapsed 2-5 years after diagnosis (median PFS 18.5 months; OS 71.9 months), or late relapse group (median PFS 31.6 months; median OS 87.8 months; p<0.001) (Figure 1).

Conclusions

Early relapse (<2 years) is an indicator for shorter duration of response to subsequent treatments, and worse OS. Treatment with upfront ASCT and achieving VGPR or better after first line therapy lower the risk of early relapse. The only parameter that is predictive for both early and late relapse is HR FISH features. Although factors that predict worse survival in MM are well defined, further studies are needed to identify predictors of a more indolent disease course so that future therapeutic approaches can be tailored to each individual.

Figure 1

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Figure 1

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