Drivers of treatment patterns in patients with chronic lymphocytic leukemia stopping ibrutinib or idelalisib therapies

Outcomes with ibrutinib in patients with chronic lymphocytic leukaemia: Results from the German multicentre REALITY study

OBJECTIVES

To assess treatment adherence, effectiveness and safety outcomes of patients with chronic lymphocytic leukaemia (CLL) receiving ibrutinib in a real-world setting.

METHODS

Patients enrolled in REALITY were ≥18 years with a confirmed diagnosis of CLL and were receiving ibrutinib as a first-line (1L), 2L or ≥3L therapy. Treatment retention, adherence, progression-free survival (PFS), overall survival (OS) and time to next therapy were assessed at 1 and 2 years overall, by typology and by cytogenetic subgroups. PFS and OS were analysed using Kaplan-Meier methods.

RESULTS

Exactly 302 patients were enrolled across 57 sites in Germany, from January 2017 to July 2021. One-year retention rates were 69.9% overall (primary endpoint), 77.9% for 1L patients, and 77.6%/78.8% for high-risk patients with del17p/TP53. At 2 years, PFS/OS rates were 77.8%/90.7% overall (1L, 82.7%/90.4%), and were consistent across cytogenetic subgroups. PFS rates were higher for 1L versus ≥3L patients. Patients with the low-acceptance/low-control typology at baseline were less likely to retain treatment at 1 year versus the high-acceptance/high-control typology. No new safety signals were observed.

CONCLUSIONS

The REALITY study provides further evidence of the effectiveness and safety of ibrutinib in patients with CLL in a real-world setting, particularly in earlier treatment lines.

Ibrutinib discontinuation and associated factors in a real-world national sample of elderly Medicare beneficiaries with chronic lymphocytic leukemia

Prior studies evaluating ibrutinib discontinuation are limited to clinical trials and selected medical centers and hence may not reflect real-world practice. This study used Medicare claims (2013-2019) to examine ibrutinib discontinuation and associated factors among elderly patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). Over a median follow-up of 2.1 years, two-thirds (65.2%) of the 11,870 new ibrutinib initiators were discontinued, with half (45.1%) of patients discontinuing within 12 months of initiation. Factors such as advanced age, lack of Part D low-income subsidy, evidence of prior CLL/SLL treatment, and cardiovascular comorbidities (e.g. atrial fibrillation) were associated with higher risk of discontinuation. Over a median of 1.2 years from discontinuation, 40% of discontinuers initiated another CLL/SLL treatment after ibrutinib discontinuation; 25% of patients restarted ibrutinib treatment at some point over follow-up. Our findings point to a large unmet need with the widely used BTKi ibrutinib and underscore the importance of ongoing development of efficacious and well-tolerated CLL/SLL therapies.

Real-world time to discontinuation of first-line venetoclax + obinutuzumab in chronic lymphocytic leukemia/small lymphocytic lymphoma

OBJECTIVE

To evaluate the time to discontinuation (TTD) and baseline characteristics among patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) treated with first-line (1L) venetoclax + obinutuzumab (VO) in the United States.

METHODS

A nationwide electronic health record-derived database was used to select adults with CLL/SLL initiating a 1L venetoclax-based regimen between April 11, 2016-July 31, 2020. Study measures included TTD (defined as >120-day treatment gap or switching therapy) and baseline characteristics by discontinuation status.

RESULTS

A total of 113 patients receiving 1L VO on/before July 31, 2020 were eligible for analysis (mean age: 65.9 years; 31.9% women). During the first 60 days post-treatment initiation, 3.5% had tumor lysis syndrome (TLS). The proportion of patients using corticosteroids, anti-hyperuricemics, and anti-emetics was higher during the first 60 days post-treatment initiation (100.0%, 78.8%, and 52.2%, respectively) than the period from day 61 onward (67.0%, 45.5%, and 33.9%, respectively). Mean (median) duration of active treatment was 11.6 (12.1) months; 16.8% discontinued treatment before completing 12 cycles, 68.1% completed ≥12 cycles (among which 29.9% completed ≥15 cycles), and 15.0% who did not discontinue treatment were censored before completing 12 cycles. Kaplan-Meier analysis showed that median TTD was 13.8 months. Relative to those completing ≥12 cycles, patients discontinuing treatment before completing the prescribed 12 cycles were older (70.4 vs. 65.1 years) and had poorer renal function (36.8% vs. 13.0% with creatinine clearance <60 mL/min).

CONCLUSION

A small proportion of CLL/SLL patients who were older and had poorer baseline renal function discontinued 1L VO prior to completing 12 treatment cycles. Additionally, treatment utilization, including medications related to TLS mitigation and management, was more intense during the initiation phase of VO. Further research with longer follow-up to assess long-term outcomes of VO treatment after early discontinuation is warranted.

When can cancer patient treatment nonadherence be considered intentional or unintentional? A scoping review

BACKGROUND

Treatment nonadherence in cancer patients remains high with most interventions having had limited success. Most studies omit the multi-factorial aspects of treatment adherence and refer to medication adherence. The behaviour is rarely defined as intentional or unintentional.

AIM

The aim of this Scoping Review is to increase understanding of modifiable factors in treatment nonadherence through the relationships that physicians have with their patients. This knowledge can help define when treatment nonadherence is intentional or unintentional and can assist in predicting cancer patients at risk of nonadherence and in intervention design. The scoping review provides the basis for method triangulation in two subsequent qualitative studies: 1. Sentiment analysis of online cancer support groups in relation to treatment nonadherence; 2. A qualitative validation survey to refute / or validate claims from this scoping review. Thereafter, framework development for a future (cancer patient) online peer support intervention.

METHODS

A Scoping Review was performed to identify peer reviewed studies that concern treatment / medication nonadherence in cancer patients-published between 2000 to 2021 (and partial 2022). The review was registered in the Prospero database CRD42020210340 and follows the PRISMA-S: an extension to the PRISMA Statement for Reporting Literature Searches in Systematic Searches. The principles of meta-ethnography are used in a synthesis of qualitative findings that preserve the context of primary data. An aim of meta-ethnography is to identify common and refuted themes across studies. This is not a mixed methods study, but due to a limited qualitativevidence base and to broaden findings, the qualitative elements (author interpretations) found within relevant quantitative studies have been included.

RESULTS

Of 7510 articles identified, 240 full texts were reviewed with 35 included. These comprise 15 qualitative and 20 quantitative studies. One major theme, that embraces 6 sub themes has emerged: 'Physician factors can influence patient factors in treatment nonadherence'. The six (6) subthemes are: 1. Suboptimal Communication; 2. The concept of Information differs between Patient and Physician; 3.Inadequate time. 4. The need for Treatment Concordance is vague or missing from concepts; 5. The importance of Trust in the physician / patient relationship is understated in papers; 6. Treatment concordance as a concept is rarely defined and largely missing from studies.

LINE OF ARGUMENT WAS DRAWN

Treatment (or medication) nonadherence that is intentional or unintentional is often attributed to patient factors-with far less attention to the potential influence of physician communication factors. The differentation between intentional or unintentional nonadherence is missing from most qualitative and quantitative studies. The holistic inter-dimensional / multi-factorial concept of 'treatment adherence' receives scant attention. The main focus is on medication adherence / nonadherence in the singular context. Nonadherence that is unintentional is not necessarily passive behaviour and may overlap with intentional nonadherence. The absence of treatment concordance is a barrier to treatment adherence and is rarely articulated or defined in studies.

CONCLUSION

This review demonstrates how cancer patient treatment nonadherence is often a shared outcome. An equal focus on physican and patient factors can increase understanding of the two main types of nonadherence (intentional or unintentional). This differentation should help improve the fundamentals of intervention design.

PI3K inhibitors in chronic lymphocytic leukemia: where do we go from here?

Phosphatidylinositol 3-kinase (PI3K) inhibitors are effective in chronic lymphocytic leukemia (CLL). However, the severe toxicity profile associated with the first-generation inhibitors idelalisib and duvelisib, combined with the availability of other more tolerable agents, have limited their use. CLL is still considered incurable, and relapse after treatment, development of resistance, and treatment intolerance are common. It is therefore of interest to optimize the administration of currently approved PI3K inhibitors and to develop next-generation agents to improve tolerability, so that this class of agents will be considered an effective and safe treatment option when needed. These efforts are reflected in the large number of emerging clinical trials with PI3K inhibitors in CLL. Current strategies to overcome treatment limitations include intermittent dosing, which is established for copanlisib and zandelisib and under investigation for duvelisib and parsaclisib. A second strategy is to combine the PI3K inhibitor with another novel agent, either as a continuous regimen or a fixedduration regimen, to deepen responses. In addition to these approaches, it is of interest to identify higher-resolution actionable biomarkers that can predict treatment responses and toxicity, and inform personalized treatment decisions. Here, we discuss the current status of PI3K inhibitors in CLL, factors limiting the use of currently approved PI3K inhibitors in CLL, current strategies to overcome these limitations, and where to go next.

Pirtobrutinib in relapsed or refractory B-cell malignancies (BRUIN): a phase 1/2 study

BACKGROUND

Covalent Bruton's tyrosine kinase (BTK) inhibitors are efficacious in multiple B-cell malignancies, but patients discontinue these agents due to resistance and intolerance. We evaluated the safety and efficacy of pirtobrutinib (working name; formerly known as LOXO-305), a highly selective, reversible BTK inhibitor, in these patients.

METHODS

Patients with previously treated B-cell malignancies were enrolled in a first-in-human, multicentre, open-label, phase 1/2 trial of the BTK inhibitor pirtobrutinib. The primary endpoint was the maximum tolerated dose (phase 1) and overall response rate (ORR; phase 2). This trial is registered with ClinicalTrials.gov, NCT03740529.

FINDINGS

323 patients were treated with pirtobrutinib across seven dose levels (25 mg, 50 mg, 100 mg, 150 mg, 200 mg, 250 mg, and 300 mg once per day) with linear dose-proportional exposures. No dose-limiting toxicities were observed and the maximum tolerated dose was not reached. The recommended phase 2 dose was 200 mg daily. Adverse events in at least 10% of 323 patients were fatigue (65 [20%]), diarrhoea (55 [17%]), and contusion (42 [13%]). The most common adverse event of grade 3 or higher was neutropenia (32 [10%]). There was no correlation between pirtobrutinib exposure and the frequency of grade 3 treatment-related adverse events. Grade 3 atrial fibrillation or flutter was not observed, and grade 3 haemorrhage was observed in one patient in the setting of mechanical trauma. Five (1%) patients discontinued treatment due to a treatment-related adverse event. In 121 efficacy evaluable patients with chronic lymphocytic leukaemia (CLL) or small lymphocytic lymphoma (SLL) treated with a previous covalent BTK inhibitor (median previous lines of treatment 4), the ORR with pirtobrutinib was 62% (95% CI 53-71). The ORR was similar in CLL patients with previous covalent BTK inhibitor resistance (53 [67%] of 79), covalent BTK inhibitor intolerance (22 [52%] of 42), BTK C481-mutant (17 [71%] of 24) and BTK wild-type (43 [66%] of 65) disease. In 52 efficacy evaluable patients with mantle cell lymphoma (MCL) previously treated with covalent BTK inhibitors, the ORR was 52% (95% CI 38-66). Of 117 patients with CLL, SLL, or MCL who responded, all but eight remain progression-free to date.

INTERPRETATION

Pirtobrutinib was safe and active in multiple B-cell malignancies, including patients previously treated with covalent BTK inhibitors. Pirtobrutinib might address a growing unmet need for alternative therapies for these patients.

FUNDING

Loxo Oncology.

Managing toxicities of phosphatidylinositol-3-kinase (PI3K) inhibitors

Despite the proven effective approach to targeting the phosphatidylinositol-3-kinase (PI3K) pathway in B-cell malignancies, the approved PI3K inhibitors idelalisib and duvelisib have been less commonly selected for patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), given the availability of other more tolerable agents. However, patients with CLL/SLL can experience a disease course that is multiply relapsed, refractory, or intolerant to treatment, and PI3K inhibitors can achieve meaningful responses. This article reviews the common early- and late-onset (considered immune-mediated) toxicities with PI3K inhibitors, including infections, hepatotoxicity, diarrhea and/or colitis, and pneumonitis. Data on pretreatment considerations, toxicity management, and drug rechallenge are presented. In addition, next-generation PI3K inhibitors and novel treatment approaches with PI3K inhibitors, including combinations, time-limited treatments, and intermittent dosing, are highlighted.

Rituximab biosimilars in hematologic malignancies: the need for a real-world approach

The introduction of rituximab biosimilars into healthcare systems can potentially help to control healthcare costs for the treatment of hematologic malignancies. However, there are currently several barriers to the uptake of biosimilars. This review discusses barriers to the adoption of rituximab biosimilars by stakeholders including patients and healthcare providers. We outline the importance of utilizing real-world evidence in providing additional clinical experience on rituximab biosimilars in hematologic malignancies to improve stakeholder confidence regarding their efficacy and safety. We conclude by offering recommendations for designing and conducting effective real-world studies. Such studies can provide evidence to help achieve lower-priced biologics and improved patient access to help sustain the treatment of hematologic malignancies with biologics, including rituximab biosimilars.

Comparison of Time to Next Treatment, Health Care Resource Utilization, and Costs in Patients with Chronic Lymphocytic Leukemia Initiated on Front-line Ibrutinib or Chemoimmunotherapy

BACKGROUND

Studies assessing ibrutinib's economic burden versus chemoimmunotherapy (CIT) focused on pharmacy costs but not medical costs. This study compared time to next treatment (TTNT), health care resource utilization (HRU), and total direct costs among patients with chronic lymphocytic leukemia (CLL) initiating front-line ibrutinib single agent (Ibr) or CIT.

MATERIALS AND METHODS

Optum Clinformatics Extended DataMart De-Identified Databases were used to identify adults with ≥ 2 claims with a CLL diagnosis initiating front-line Ibr or CIT from February 12, 2014 to June 30, 2017. Inverse probability of treatment weighting was used to control for potential differences in baseline characteristics between the Ibr and CIT cohorts. Two periods were considered: entire front-line therapy (until initiation of second-line therapy) and first 6 months of front-line therapy. Comparisons with a subgroup of CIT patients initiating bendamustine/rituximab (BR) were also conducted.

RESULTS

TTNT was significantly longer for Ibr (N = 322) relative to CIT (N = 839; hazard ratio, 0.54; P = .0163; Kaplan-Meier rates [24 months]: Ibr = 88.6%, CIT = 75.9%) and the subset of CIT patients treated with BR (N = 455; hazard ratio, 0.54; P = .0208; Kaplan-Meier rates [24 months]: Ibr = 89.0%, BR = 79.0%). During the entire front-line therapy, Ibr patients had significantly fewer monthly days with outpatient visits (rate ratio = 0.75; P = .0200). Ibrutinib's higher pharmacy costs (mean monthly cost difference [MMCD] = $6,849; P < .0001) were offset by lower medical costs (MMCD = -$10,615; P < .0001), yielding net savings (MMCD = -$3,766; P < .0001) versus CIT. Ibr was associated with net savings (MMCD = -$5,569; P < .0001) versus BR. Cost savings and reductions in HRU were more pronounced during the first 6 months of front-line therapy.

CONCLUSION

During front-line CLL treatment, Ibr was associated with longer TTNT, fewer monthly days with outpatient visits, and net monthly total cost reduction versus CIT and BR.

Descriptive analysis of dosing and outcomes for patients with ibrutinib-treated relapsed or refractory chronic lymphocytic leukemia in a Canadian centre

Background

Ibrutinib is an approved treatment for relapsed or refractory chronic lymphocytic leukemia (cll) and small lymphocytic lymphoma (sll). The effect of ibrutinib dose reduction compared with discontinuation in a population-based setting is unclear.

Methods

To examine the patterns of ibrutinib use in a Canadian population-based setting, we analyzed a retrospective cohort of patients with relapsed or refractory cll or sll treated with ibrutinib.

Results

The 64 patients diagnosed with cll or sll had a median age of 76.5 years. Most had unmutated ighv (immunoglobulin variable heavy chain). A hematologic response occurred in 39 patients regardless of the ibrutinib dose. The most common toxicities were infection, bruising or bleeding, and musculoskeletal problems, with a median time to first toxicity of 14 days. More than half the cohort experienced a dose reduction, with musculoskeletal problems, cytopenias, and infection being the leading causes; surgery was the most frequent indication for holding treatment. Only 26 of the 64 patients (40.6%) stayed on the recommended maximal dose of ibrutinib. No differences in reported toxicities or hematologic response rates were evident between the patients receiving maximal and submaximal therapy. At the end of the study period, 53 patients from the initial cohort remained on ibrutinib.

Conclusions

More than half the study patients received ibrutinib therapy at a submaximal dose without evidence of increased frequency of toxicities or disease progression. The rate of ibrutinib discontinuation was lower in our cohort than has been reported in other settings. Submaximal ibrutinib dosing will have to be further systematically evaluated.

A pilot study of lower doses of ibrutinib in patients with chronic lymphocytic leukemia

Ibrutinib is highly efficacious and used at 420 mg/d for treatment of chronic lymphocytic leukemia (CLL). We previously demonstrated a decline in Bruton's tyrosine kinase (BTK) protein levels in CLL cells after 1 cycle of ibrutinib, suggesting ibrutinib dose could be lowered after the first cycle without loss of biological effect. To test this postulate, a pilot study (NCT02801578) was designed to systematically reduce ibrutinib dosing within the same patient with CLL over the course of three 28-day cycles. After an initial cycle of 420 mg/d, the dose was reduced to 280 mg/d in cycle 2, and then to 140 mg/d in cycle 3. Eleven patients began study treatment, and 9 completed the 3 cycles. Plasma and intracellular pharmacokinetics (PK), BTK occupancy, and pharmacodynamic (PD) response at different doses of ibrutinib were compared. Plasma and intracellular levels of ibrutinib were dose-dependent, and even the lowest dose was sufficient to occupy, on average, more than 95% of BTK protein. In concert, BTK downstream signaling inhibition was maintained with 140 mg/d ibrutinib in cycle 3, and there were comparable reductions in total and phospho-BTK (Tyr223) protein levels across 3 cycles. Reductions of plasma chemokine CCL3 and CCL4 levels, considered to be biomarkers of ibrutinib response, were similar during the 3 cycles. These PK/PD data demonstrate that after 1 cycle of ibrutinib at the standard 420 mg/d dose, the dose can be reduced without losing biological activity. Clinical efficacy of lower doses needs to be systematically evaluated. Such dose reductions would lower drug cost, lessen untoward toxicity, and facilitate rationale-based combinations. This trial was registered at www.clinicaltrials.gov as #NCT02801578.