Many patients with chronic lymphocytic leukemia (CLL) develop cytogenetic abnormalities, which are typically predictive of poorer outcomes. However, prior reports have noted that fluorescence in situ hybridization (FISH) and IGHV testing rates before initiating a subsequent therapy have been suboptimal (Mato A, et al. Br J Haematol. 2016). This analysis utilizes data from the informCLL registry to describe rates of prognostic testing in patients with CLL who were stratified by line of therapy, proportions of patients with specific abnormalities, and current treatment patterns in clinical practice.
Consenting eligible patients were at least 18 years of age and initiated CLL treatment within 30 days of enrollment. First treatment at enrollment was classified into 5 groups: chemoimmunotherapy (CIT), chemotherapy (CT), immunotherapy, ibrutinib, and other novel agents. At time of analysis, the registry listed 459 previously untreated patients and 381 with relapsed or refractory (R/R) CLL. The median age was 70 years and the majority (64%) of patients were male.
Researchers found that prognostic biomarker testing was performed infrequently. Among all patients (n = 840), only 262 (31%) had FISH testing, 89 (11%) had testing performed for TP53 mutation, and 94 (11%) had testing for IGHV mutational status. Rates were consistently low for testing prior to first-line treatment and before initiating next-line treatment among R/R patients.
Among patients who were tested, substantial proportions were found to have cytogenetic abnormalities. A total of 70 of 262 (27%) patients had del(17p), 23 of 89 (26%) had mutated TP53, and 69 of 94 (73%) had unmutated IGHV. Del(17p) and TP53 mutation rates were similar for previously untreated and R/R patients who were tested, but unmutated IGHV rates were higher among R/R patients (87%) compared with previously untreated patients (64%).
In accordance with National Comprehensive Cancer Network recommendations, among 70 patients with del(17p), the most common treatment was ibrutinib (54%); however, a considerable proportion of patients received CT/CIT (34%). Among 69 patients with unmutated IGHV, 43% were treated with ibrutinib and 42% with CIT.
These findings suggest that prognostic testing patterns in the real-world setting remain suboptimal although they are recommended by consensus guidelines. These results underscore a need to educate providers and payers on how to utilize these markers to guide CLL treatment decisions for optimal clinical outcomes.
Mato AR, et al. ASH 2018. Abstract 4425.