Single-agent ibrutinib in RESONATE-2™ and RESONATE™ versus treatments in the real-world PHEDRA databases for patients with chronic lymphocytic leukemia

Overall survival of patients with CLL treated with ibrutinib in the first line compared to second-line ibrutinib after chemotherapy/chemoimmunotherapy

OBJECTIVE

To evaluate the overall survival (OS) of patients with chronic lymphocytic leukemia (CLL) receiving either ibrutinib monotherapy as a first-line (1L) treatment or chemotherapy/chemoimmunotherapy-based (CT/CIT) regimens in 1L followed by ibrutinib in the second line (1L CT/CIT-2L ibrutinib) after disease progression by emulating a randomized trial comparing both treatment sequences.

METHODS

Patient-level data from the RESONATE-2 trial (NCT01722487) and real-world PHEDRA databases were analyzed. Three scenarios were considered using the following data sources: (1) RESONATE-2, (2) combined RESONATE-2/PHEDRA, (3) combined RESONATE-2/PHEDRA for 1L ibrutinib and PHEDRA for 1L CT/CIT-2L ibrutinib. Propensity score-based weights and inverse probability of censoring weighting were used to adjust for baseline (Scenarios 2 and 3) and time-dependent confounding (all scenarios), and to address potential biases. A weighted Cox proportional hazards model was used to estimate the OS hazard ratio (HR) and 95% confidence interval (CI) for 1L ibrutinib versus 1L CT/CIT-2L ibrutinib.

RESULTS

Results from Scenario 1 showed a significantly lower risk of death with 1L ibrutinib compared with 1L chlorambucil followed by 2L ibrutinib (HR 0.35 [95% CI 0.20-0.62]). Results from Scenarios 2 and 3 demonstrated a reduced risk of death with 1L ibrutinib compared with 1L CT/CIT-2L ibrutinib (HR 0.35 [0.21-0.61] and 0.64 [0.39-1.04], respectively).

CONCLUSION

The analyses consistently showed a reduced risk of death when ibrutinib was used as a 1L treatment in CLL compared with delaying its use until 2L after CT/CIT regimens, which suggests that initiating ibrutinib in 1L is advantageous for improving survival outcomes.

Systematic Literature Review of Real-World Effectiveness Results Data for First-Line Ibrutinib in Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma

BACKGROUND AND OBJECTIVE

Ibrutinib, an oral Bruton's tyrosine kinase inhibitor, has demonstrated efficacy as a first-line treatment for chronic lymphocytic leukemia in multiple, phase III, randomized clinical trials. This systematic literature review assessed the clinical effectiveness of ibrutinib in the first-line treatment of chronic lymphocytic leukemia in real-world clinical settings.

METHODS

MEDLINE, EMBASE, and relevant conference websites were searched for articles published in the USA from 1 January, 2014 to 30 June, 2020. Overall survival, progression-free survival, overall response rate, and time to next treatment were summarized.

RESULTS

This analysis included a total of 12 publications representing data from 112 to 2033 patients from community and academic centers, and the multicenter informCLL registry. Patients were predominantly male (60-99%) with a median age range from 62 to 77 years, and included those with high-risk genomic features (del[17p]: 21-33%; del[11q]: 33%; and unmutated immunoglobulin heavy chain variable gene: 59%). Real-world effectiveness with ibrutinib complemented the efficacy demonstrated in randomized clinical trials. Across various studies, the 12-month overall survival rates ranged from 95% to 96%; 18-month overall survival rates were similarly high (91%). Twelve-month progression-free survival rates ranged from 89% to 93%, and the overall response rate ranged from 71% to 90% across four studies. In the studies that reported time to next treatment, 91% and 87% of patients treated with first-line ibrutinib did not initiate new treatment at 12 months and 24 months, respectively.

CONCLUSIONS

This systematic literature review confirms the benefit of ibrutinib as a first-line treatment in patients with chronic lymphocytic leukemia in real-world clinical settings and is consistent with results from randomized clinical trials, including in patients with high-risk genomic features.

Approaches to Selecting "Time Zero" in External Control Arms with Multiple Potential Entry Points: A Simulation Study of 8 Approaches

BACKGROUND

When including data from an external control arm to estimate comparative effectiveness, there is a methodological choice of when to set "time zero," the point at which a patient would be eligible/enrolled in a contemporary study. Where patients receive multiple lines of eligible therapy and thus alternative points could be selected, this issue is complex.

METHODS

A simulation study was conducted in which patients received multiple prior lines of therapy before entering either cohort. The results from the control and intervention data sets are compared using 8 methods for selecting time zero. The base-case comparison was set up to be biased against the intervention (which is generally received later), with methods compared in their ability to estimate the true intervention effectiveness. We further investigate the impact of key study attributes (such as sample size) and degree of overlap in time-varying covariates (such as prior lines of therapy) on study results.

RESULTS

Of the 8 methods, 5 (all lines, random line, systematically selecting groups based on mean absolute error, root mean square error, or propensity scores) showed good performance in accounting for differences between the line at which patients were included. The first eligible line can be statistically inefficient in some situations. All lines (with censoring) cannot be used for survival outcomes. The last eligible line cannot be recommended.

CONCLUSIONS

Multiple methods are available for selecting the most appropriate time zero from an external control arm. Based on the simulation, we demonstrate that some methods frequently perform poorly, with several viable methods remaining. In selecting between the viable methods, analysts should consider the context of their analysis and justify the approach selected.

HIGHLIGHTS

There are multiple methods available from which an analyst may select "time zero" in an external control cohort.This simulation study demonstrates that some methods perform poorly but most are viable options, depending on context and the degree of overlap in time zero across cohorts.Careful thought and clear justification should be used when selecting the strategy for a study.

Effectiveness of crizotinib versus entrectinib in ROS1-positive non-small-cell lung cancer using clinical and real-world data

Aims: To compare clinical trial results for crizotinib and entrectinib in ROS1-positive non-small-cell lung cancer and compare clinical trial data and real-world outcomes for crizotinib. Patients & methods: We analyzed four phase I-II studies using a simulated treatment comparison (STC). A STC of clinical trial versus real-world evidence compared crizotinib clinical data to real-world outcomes. Results: Adjusted STC found nonsignificant trends favoring crizotinib over entrectinib: objective response rate, risk ratio = 1.04 (95% CI: 0.85-1.28); median duration of response, mean difference = 16.11 months (95% CI: -1.57- 33.69); median progression-free survival, mean difference = 3.99 months (95% CI: -6.27-14.25); 12-month overall survival, risk ratio = 1.01 (95% CI: 0.90-1.12). Nonsignificant differences were observed between the trial end point values and the real-world evidence for crizotinib. Conclusions: Crizotinib and entrectinib have comparable efficacy in ROS1-positive non-small-cell lung cancer.

Real-world Clinical Outcomes of First-Line Ibrutinib or Chemoimmunotherapy in Patients with Chronic Lymphocytic Leukemia by Risk Status

INTRODUCTION

Certain genetic features in chronic lymphocytic leukemia (CLL) are associated with inferior outcomes after chemoimmunotherapy (CIT). This retrospective study evaluated treatment patterns and clinical outcomes of patients with CLL, stratified into high-risk and non-high-risk groups, who received first-line ibrutinib or CIT therapy.

METHODS

High-risk group included confirmed presence of del(17p), del(11q), unmutated IGHV, TP53 mutations, or complex karyotype. Weighted high-risk ibrutinib and CIT groups were compared for treatment effects using inverse probability of treatment weighting. Hazard ratios [95% CI] (HR) for time to next treatment (TTNT) were analyzed using Kaplan-Meier curves.

RESULTS

Bendamustine/rituximab was the most common CIT regimen initiated for high-risk patients. During the available follow-up (median 34-35 months), 74.7% of the weighted high-risk ibrutinib group received only one line of treatment, compared with 47.2% of the weighted high-risk CIT group. The most common second-line treatment was ibrutinib for those in the CIT groups and venetoclax for the ibrutinib groups. The weighted high-risk ibrutinib group had a significantly longer TTNT (median not reached) than the weighted high-risk CIT group (median 34.4 months) and was 54% less likely to start a new treatment (HR 0.5 [0.3-0.6], P < 0.010). Among CIT-treated groups, high-risk patients had significantly shorter median TTNT than non-high-risk patients (P < 0.010). However, within the ibrutinib-treated groups, the median TTNT was similar between high-risk and non-high-risk patients (HR 2.2 [1.0-5.0]; P = 0.060).

CONCLUSION

This study found that first-line single-agent ibrutinib therapy was associated with significantly longer TTNT than CIT regimens in real-world patients with high-risk CLL. The results support the use of ibrutinib in high-risk patients. INFOGRAPHIC.

Real-World Characteristics and Outcome of Patients Treated With Single-Agent Ibrutinib for Chronic Lymphocytic Leukemia in Spain (IBRORS-LLC Study)

BACKGROUND

Ibrutinib demonstrated remarkable efficacy and favorable tolerability in patients with untreated or relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL), including those with high-risk genetic alterations. The IBRORS-CLL study assessed the characteristics, clinical management and outcome of CLL patients receiving ibrutinib in routine clinical practice in Spain.

PATIENTS

Observational, retrospective, multicenter study in CLL patients who started single-agent ibrutinib as first-line treatment or at first or second relapse between January 2016 and January 2019.

RESULTS

A total of 269 patients were included (median age: 70.9 years; cardiovascular comorbidity: 55.4%, including hypertension [47.6%] and atrial fibrillation [AF] [7.1%]). Overall, 96.7% and 69% of patients underwent molecular testing for del(17p)/TP53 mutation and IGHV mutation status. High-risk genetic features included unmutated IGHV (79%) and del(17p)/TP53 mutation (first-line: 66.3%; second-line: 23.1%). Overall, 84 (31.2%) patients received ibrutinib as first-line treatment, and it was used as second- and third-line therapy in 121 (45.0%) and 64 (23.8%) patients. The median progression-free survival and overall survival were not reached irrespective of del(17p)/TP53, or unmutated IGHV. Common grade ≥3 adverse events were infections (12.2%) and bleeding (3%). Grade ≥3 AF occurred in 1.5% of patients.

CONCLUSION

This real-world study shows that single-agent ibrutinib is an effective therapy for CLL, regardless of age and high-risk molecular features, consistent with clinical trials. Additionally, single-agent ibrutinib was well tolerated, with a low rate of cardiovascular events. This study also emphasized a high molecular testing rate of del(17p)/TP53 mutation and IGHV mutation status in clinical practice according to guideline recommendations.

Screening and monitoring of the BTKC481S mutation in a real-world cohort of patients with relapsed/refractory chronic lymphocytic leukaemia during ibrutinib therapy

The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib has revolutionised the therapeutic landscape of chronic lymphocytic leukaemia (CLL). Acquired mutations emerging at position C481 in the BTK tyrosine kinase domain are the predominant genetic alterations associated with secondary ibrutinib resistance. To assess the correlation between disease progression, and the emergence and temporal dynamics of the most common resistance mutation BTK^C481S , sensitive (10^-4 ) time-resolved screening was performed in 83 relapsed/refractory CLL patients during single-agent ibrutinib treatment. With a median follow-up time of 40 months, BTK^C481S was detected in 48·2% (40/83) of the patients, with 80·0% (32/40) of them showing disease progression during the examined period. In these 32 cases, representing 72·7% (32/44) of all patients experiencing relapse, emergence of the BTK^C481S mutation preceded the symptoms of clinical relapse with a median of nine months. Subsequent Bcl-2 inhibition therapy applied in 28/32 patients harbouring BTK^C481S and progressing on ibrutinib conferred clinical and molecular remission across the patients. Our study demonstrates the clinical value of sensitive BTK^C481S monitoring with the largest longitudinally analysed real-world patient cohort reported to date and validates the feasibility of an early prediction of relapse in the majority of ibrutinib-treated relapsed/refractory CLL patients experiencing disease progression.

TP53 dysfunction in chronic lymphocytic leukemia: clinical relevance in the era of B-cell receptors and BCL-2 inhibitors

INTRODUCTION

Patients with TP53 dysfunction, assessed by del(17p) or TP53 mutations, respond poorly to chemo-immunotherapy and fare better with the new therapies (BCR and BCL-2 inhibitors); however, it is unclear whether their response is similar to that of patients without anomalies or whether there is currently an adequate determination of TP53 dysfunction.

AREA COVERED

A literature search was undertaken on clinical trials and real-world experience data on patients with TP53 dysfunction treated with different protocols. Moreover, data on the TP53 biological function and on the tests currently employed for its assessment were reviewed.

EXPERT OPINION

Although TP53 dysfunction has less negative influence on the new biological therapies, patients with these alterations, particularly those with biallelic inactivation of TP53, have a worst outcome with these therapies than those without alterations. At present, a determination of TP53, particularly with next generation sequencing (NGS) methodologies, may be sufficient for the identifications of the patients unsuitable for chemo-immunotherapy, although integration with del(17p) would be advisable. For the future, more extensive determinations of the TP53 status, including functional assays, may become part of the current armamentarium for a better patient stratification and treatment with newer protocols.

Novel aspects on gonadotoxicity and fertility preservation in lymphoproliferative neoplasms

The topic of fertility preservation in patients with a lymphoproliferative disease offers new aspects of debate, due to the introduction of novel chemotherapeutic regimens and small molecules in the clinical landscape. Cancer related infertility is mostly dependent on gonadotoxic treatments and fertile female patients are today addressed to the oocyte cryopreservation or to ovarian cortex fragment cryopreservation. These methods present advantages and disadvantages, which will be discussed in the present review, together with the options for male patients. The recent discovery of functional ovarian stem cells (OCSs) in woman ovarian cortex, opens new avenues offering a innovative procedure for fertility preservation through as model of regenerative medicine. Here, we review the gonadotoxic potential of "classical" chemotherapeutic treatments as well as of "novel" targeted therapies actually employed for lymphoproliferative neoplasms in young patients and revisit both the today available and future chances to preserve and restore fertility after the cancer healing.

Comparison of real-world treatment patterns in chronic lymphocytic leukemia management before and after availability of ibrutinib in the province of British Columbia, Canada

We performed a retrospective study comparing treatment patterns and overall survival (OS) in chronic lymphocytic leukemia (CLL) patients with the advent of ibrutinib to provide current real-world data.

METHODS

Using a provincial population-based database, we analyzed CLL patients who received upfront treatment in British Columbia before ibrutinib availability (1984-2014), during ibrutinib access for: relapse only (2014-2015) and for upfront treatment of patients (with 17p deletion or unfit for chemotherapy) (2015-2016). Analysis included up to third-line treatment.

RESULTS

Of 1729 patients meeting inclusion criteria (median age, 66 years; 1466, period 1; 140, period 2; 123, period 3), FR was the most common first-line therapy (35.8 %, 54.3 % and 40.7 %, periods 1-3, respectively) and 18.7 % received ibrutinib upfront in period 3. The most common therapies in relapse were chemoimmunotherapy (36.1 % and 55.6 %, periods 1 and 2, second-line; 29.2 %, period 1, third-line) and ibrutinib (69.8 %, period 3, second-line; 46.4 % and 70.3 %, periods 2 and 3, third-line). OS improved for patients treated in periods 2-3 over period 1 (median OS not reached vs. 11.9 years, p < 0.001; no difference in OS for periods 2-3, p = 0.385).

CONCLUSION

Ibrutinib has replaced chemoimmunotherapy as the preferred therapy in relapse. Overall survival has improved over time with access to ibrutinib.