How to determine post-FCR therapy for cytogenetic risk-tailored elderly patients with chronic lymphocytic leukemia, maintenance rituximab or observation

Maintenance therapy for chronic lymphocytic leukaemia

BACKGROUND

Chronic lymphocytic leukaemia (CLL) is the most common lymphoproliferative disease in adults and currently remains incurable. As the progression-free period shortens after each successive treatment, strategies such as maintenance therapy are needed to improve the degree and duration of response to previous therapies. Monoclonal antibodies, immunomodulatory agents, and targeted therapies are among the available options for maintenance therapy. People with CLL who achieve remission after previous therapy may choose to undergo medical observation or maintenance therapy to deepen the response. Even though there is widespread use of therapeutic maintenance agents, the benefits and harms of these treatments are still uncertain.

OBJECTIVES

To assess the effects and safety of maintenance therapy, including anti-CD20 monoclonal antibody, immunomodulatory drug therapy, anti-CD52 monoclonal antibody, Bruton tyrosine kinase inhibitor, and B-cell lymphoma-2 tyrosine kinase inhibitor, for individuals with CLL.

SEARCH METHODS

We conducted a comprehensive literature search for randomised controlled trials (RCTs) with no language or publication status restrictions. We searched CENTRAL, MEDLINE, Embase, and three trials registers in January 2022 together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

We included RCTs with prospective identification of participants. We excluded cluster-randomised trials, cross-over trial designs, and non-randomised studies. We included studies comparing maintenance therapies with placebo/observation or head-to-head comparisons.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. We assessed risk of bias in the included studies using Cochrane's RoB 1 tool for RCTs. We rated the certainty of evidence for the following outcomes using the GRADE approach: overall survival (OS), health-related quality of life (HRQoL), grade 3 and 4 adverse events (AEs), progression-free survival (PFS), treatment-related mortality (TRM), treatment discontinuation (TD), and all adverse events (AEs).

MAIN RESULTS

We identified 11 RCTs (2393 participants) that met the inclusion criteria, including seven trials comparing anti-CD20 monoclonal antibodies (mAbs) (rituximab or ofatumumab) with observation in 1679 participants; three trials comparing immunomodulatory drug (lenalidomide) with placebo/observation in 693 participants; and one trial comparing anti-CD 52 mAbs (alemtuzumab) with observation in 21 participants. No comparisons of novel small molecular inhibitors were found. The median age of participants was 54.1 to 71.7 years; 59.5% were males. The type of previous induction treatment, severity of disease, and baseline stage varied among the studies. Five trials included early-stage symptomatic patients, and three trials included advanced-stage patients (Rai stage III/IV or Binet stage B/C). Six trials reported a frequent occurrence of cytogenic aberrations at baseline (69.7% to 80.1%). The median follow-up duration was 12.4 to 73 months. The risk of selection bias in the included studies was unclear. We assessed overall risk of performance bias and detection bias as low risk for objective outcomes and high risk for subjective outcomes. Overall risk of attrition bias, reporting bias, and other bias was low. Anti-CD20 monoclonal antibodies (mAbs): rituximab or ofatumumab maintenance versus observation Anti-CD20 mAbs maintenance likely results in little to no difference in OS (hazard ratio (HR) 0.94, 95% confidence interval (CI) 0.73 to 1.20; 1152 participants; 3 studies; moderate-certainty evidence) and likely increases PFS significantly (HR 0.61, 95% CI 0.50 to 0.73; 1255 participants; 5 studies; moderate-certainty evidence) compared to observation alone. Anti-CD20 mAbs may result in: an increase in grade 3/4 AEs (rate ratio 1.34, 95% CI 1.06 to 1.71; 1284 participants; 5 studies; low-certainty evidence); little to no difference in TRM (risk ratio 0.82, 95% CI 0.39 to 1.71; 1189 participants; 4 studies; low-certainty evidence); a slight reduction to no difference in TD (risk ratio 0.93, 95% CI 0.72 to 1.20; 1321 participants; 6 studies; low-certainty evidence); and an increase in all AEs (rate ratio 1.23, 95% CI 1.03 to 1.47; 1321 participants; 6 studies; low-certainty evidence) compared to the observation group. One RCT reported that there may be no difference in HRQoL between the anti-CD20 mAbs (ofatumumab) maintenance and the observation group (mean difference -1.70, 95% CI -8.59 to 5.19; 480 participants; 1 study; low-certainty evidence). Immunomodulatory drug (IMiD): lenalidomide maintenance versus placebo/observation IMiD maintenance therapy likely results in little to no difference in OS (HR 0.91, 95% CI 0.61 to 1.35; 461 participants; 3 studies; moderate-certainty evidence) and likely results in a large increase in PFS (HR 0.37, 95% CI 0.19 to 0.73; 461 participants; 3 studies; moderate-certainty evidence) compared to placebo/observation. Regarding harms, IMiD maintenance therapy may result in an increase in grade 3/4 AEs (rate ratio 1.82, 95% CI 1.38 to 2.38; 400 participants; 2 studies; low-certainty evidence) and may result in a slight increase in TRM (risk ratio 1.22, 95% CI 0.35 to 4.29; 458 participants; 3 studies; low-certainty evidence) compared to placebo/observation. The evidence for the effect on TD compared to placebo is very uncertain (risk ratio 0.71, 95% CI 0.47 to 1.05; 400 participants; 2 studies; very low-certainty evidence). IMiD maintenance therapy probably increases all AEs slightly (rate ratio 1.41, 95% CI 1.28 to 1.54; 458 participants; 3 studies; moderate-certainty evidence) compared to placebo/observation. No studies assessed HRQoL. Anti-CD52 monoclonal antibodies (mAbs): alemtuzumab maintenance versus observation Maintenance with alemtuzumab may have little to no effect on PFS, but the evidence is very uncertain (HR 0.55, 95% CI 0.32 to 0.95; 21 participants; 1 study; very low-certainty evidence). We did not identify any study reporting the outcomes OS, HRQoL, grade 3/4 AEs, TRM, TD, or all AEs.

AUTHORS' CONCLUSIONS

There is currently moderate- to very low-certainty evidence available regarding the benefits and harms of maintenance therapy in people with CLL. Anti-CD20 mAbs maintenance improved PFS, but also increased grade 3/4 AEs and all AEs. IMiD maintenance had a large effect on PFS, but also increased grade 3/4 AEs. However, none of the above-mentioned maintenance interventions show differences in OS between the maintenance and control groups. The effects of alemtuzumab maintenance are uncertain, coupled with a warning for drug-related infectious toxicity. We found no studies evaluating other novel maintenance interventions, such as B-cell receptor inhibitors, B-cell leukaemia-2/lymphoma-2 inhibitors, or obinutuzumab.

Risk-adapted, ofatumumab-based chemoimmunotherapy and consolidation in treatment-naïve chronic lymphocytic leukemia: a phase 2 study

High-risk cytogenetics and minimal residual disease (MRD) after chemoimmunotherapy (CIT) predict unfavorable outcome in chronic lymphocytic leukemia (CLL). This phase 2 study investigated risk-adapted CIT in treatment-naïve CLL (NCT01145209). Patients with high-risk cytogenetics received induction with fludarabine, cyclophosphamide, and ofatumumab. Those without high-risk cytogenetics received fludarabine and ofatumumab. After induction, MRD positive (MRD+) patients received 4 doses of ofatumumab consolidation. MRD negative (MRD-) patients had no intervention. Of 28 evaluable for response, all responded to induction and 10 (36%) achieved MRD-. Two-year progression-free survival (PFS) was 71.4% (CI₉₅, 56.5-90.3%). There was no significant difference in median PFS between the high-risk and the standard-risk groups. Ofatumumab consolidation didn't convert MRD + to MRD-. In the MRD + group, we saw selective loss of CD20 antigens during therapy. In conclusion, risk-adapted CIT is feasible in treatment-naïve CLL. Ofatumumab consolidation didn't improve depth of response in MRD + patients. Loss of targetable CD20 likely reduces efficacy of consolidation therapy.

Ofatumumab maintenance prolongs progression-free survival in relapsed chronic lymphocytic leukemia: final analysis of the PROLONG study

We report the final analysis of the PROLONG study on ofatumumab maintenance in relapsed chronic lymphocytic leukemia (CLL). In all, 480 patients with CLL in complete or partial remission after second- or third-line treatment were randomized 1:1 to ofatumumab (300 mg first week, followed by 1000 mg every 8 weeks for up to 2 years) or observation. Median follow-up duration was 40.9 months. Median progression-free survival was 34.2 and 16.9 months for ofatumumab and observation arms, respectively, (hazard ratio, 0.55 [95% confidence interval, 0.43–0.70]; P < 0.0001). Median time to next treatment for ofatumumab and observation arms, respectively, was 37.4 and 27.6 months (0.72 [0.57–0.91]; P = 0.0044). Overall survival was similar in both arms; median was not reached (0.99 [0.72–1.37]). Grade ≥ 3 adverse events occurred in 62% and 51% of patients in ofatumumab and observation arms, respectively, the most common being neutropenia (23% and 10%), pneumonia (13% and 12%) and febrile neutropenia (6% and 4%). Up to 60 days after the last treatment, four deaths were reported in the ofatumumab arm versus six in the observation arm, none considered related to ofatumumab. Ofatumumab maintenance significantly prolonged progression-free survival in patients with relapsed CLL and was well tolerated.

Ofatumumab maintenance versus observation in relapsed chronic lymphocytic leukaemia (PROLONG): an open-label, multicentre, randomised phase 3 study

BACKGROUND

Ofatumumab is a human anti-CD20 monoclonal antibody that has proven efficacy as monotherapy in refractory chronic lymphocytic leukaemia. We assessed the efficacy and safety of ofatumumab maintenance treatment versus observation for patients in remission after re-induction treatment for relapsed chronic lymphocytic leukaemia.

METHODS

This open-label, multicentre, randomised phase 3 study enrolled patients aged 18 years or older from 130 centres in 24 countries who had chronic lymphocytic leukaemia in complete or partial remission after second-line or third-line treatment. Eligible patients had a WHO performance status of 0-2, had a response assessment within the previous 3 months, did not have refractory disease, autoimmune haemolytic anaemia requiring treatment, chronic or active infection requiring treatment, and had not previously received maintenance treatment or autologous or allogeneic stem-cell transplant. Using a randomisation list generated by a central computerised system and an interactive voice recognition system, we randomly assigned (1:1) patients to receive ofatumumab (300 mg followed by 1000 mg 1 week later and every 8 weeks for up to 2 years) or undergo observation. Randomisation was stratified by number and type of previous treatment and remission status after induction treatment (block size of four). Treatment assignment was open label. The primary endpoint was investigator-assessed progression-free survival in the intention-to-treat population. We report the results of a prespecified interim analysis after two-thirds of the planned study events (disease progression or death) had happened. This trial is closed to accrual but follow-up is ongoing. This trial is registered with ClinicalTrials.gov, number NCT00802737.

FINDINGS

Between May 6, 2010, and June 19, 2014, we enrolled 474 patients: 238 patients were randomly assigned to receive ofatumumab maintenance treatment and 236 to undergo observation. One (<1%) patient in the ofatumumab group did not receive the allocated intervention (withdrawal of consent). The median follow-up was 19·1 months (IQR 10·3-28·8). Progression-free survival was improved in patients assigned to the ofatumumab group (29·4 months, 95% CI 26·2-34·2) compared with those assigned to observation (15·2 months, 11·8-18·8; hazard ratio 0·50, 95% CI 0·38-0·66; p<0·0001). The most common grade 3 or higher adverse events up to 60 days after last treatment were neutropenia (56 [24%] of 237 patients in the ofatumumab group vs 23 [10%] of 237 in the observation group) and infections (31 [13%] vs 20 [8%]). 20 (8%) of 237 patients in the ofatumumab group and three (1%) of 237 patients in the observation group had adverse events that led to permanent discontinuation of treatment. Up to 60 days after last treatment, two deaths related to adverse events occurred in the ofatumumab treatment group and five deaths related to adverse events occurred in the observation group; no deaths were attributed to the study drug.

INTERPRETATION

These data are important for the development of optimum maintenance strategies in patients with relapsed chronic lymphocytic leukaemia, notably in the present era of targeted drugs, many of which are to be used until progression.

A prospective, observational study of added medium-dose cytosine arabinoside versus As2O3 for elderly patients with acute promyelocytic leukemia

This open-label, prospective, observational study aimed to evaluate disease-free survival (DFS), overall survival (OS), PML-RARα polymerase chain reaction (PCR) monitoring and safety in elderly patients with de novo acute promyelocytic leukemia (APL) who were treated with either arsenic trioxide (As2O3) or medium-dose cytosine arabinoside (MiDAC) as frontline consolidation regimens. A total of 167 patients (age≥65 years old) received all-trans retinoic acid + daunorubicin as induction therapy. Of these patients, 22 died before attaining complete remission; the remaining 145 subjects received MiDAC- or As2O3-based consolidation therapy. As2O3 was superior to MiDAC for improving DFS and OS. This benefit appeared to result from the longer 5-year DFS (92.0 vs. 69.1%, P<0.01) and OS (94.5 vs. 79.7%, P<0.05) of As2O3 compared to MiDAC. PCR monitoring demonstrated that As2O3 promoted a lower positive rate than MiDAC (21.7 vs. 4.5%, P<0.05), but this treatment had no advantage for maintaining a low positive rate in the high-risk group. The most common life-threatening adverse drug effects in patients with MiDAC were platelet counts<25×10(9)/L (85.7%), leukocyte counts<1.0×10(9)/L (81.4%) and severe infection (84.3%). In contrast, the As2O3 regimen rarely caused leukocyte counts<1.0×10(9)/L (22.7%, P<0.01), platelet counts<25×10(9)/L (37.3%, P<0.01) or severe infection (21.3%, P<0.01). These data confirm that MiDAC should not be added during the initial consolidation of patients with APL because this treatment is far less effective, particularly in patients with a low-risk profile, and far more toxic than As2O3.