Critical Appraisal of Published Indirect Comparisons and Network Meta-Analyses of Competing Interventions for Multiple Myeloma

Carfilzomib, daratumumab, and dexamethasone (KdD) vs. lenalidomide-sparing pomalidomide-containing triplet regimens for relapsed/refractory multiple myeloma: an indirect treatment comparison

Nearly all patients with multiple myeloma eventually relapse or become refractory to treatment. Lenalidomide is increasingly administered in the frontline until disease progression or intolerance to therapy, resulting in the need for highly effective, lenalidomide-sparing options. In this study, carfilzomib plus daratumumab and dexamethasone were evaluated against lenalidomide-sparing, pomalidomide-containing triplets using matching-adjusted indirect comparison in the absence of head-to-head data. The analyses utilized long-term follow-up data from the CANDOR study (NCT03158688). Treatment with carfilzomib, daratumumab, and dexamethasone resulted in significantly longer progression-free survival (hazard ratio 0.60 [95% confidence interval: 0.37, 0.88])vs. pomalidomide plus bortezomib and dexamethasone, and numerically longer progression-free survival (hazard ratio 0.77 [95% confidence interval: 0.50, 1.08]) vs. daratumumab plus pomalidomide and dexamethasone in patients with relapsed/refractory multiple myeloma and previous lenalidomide exposure, the majority of whom were lenalidomide refractory. Carfilzomib plus daratumumab and dexamethasone offers a highly effective, lenalidomide-sparing treatment option for this population.

Network meta-analysis of efficacy of ixazomib, lenalidomide, and dexamethasone in relapsed/refractory multiple myeloma

OBJECTIVES

In the absence of head-to-head comparisons across relapsed/refractory multiple myeloma (RRMM) treatments following the approval of the oral proteasome inhibitor ixazomib, in combination with lenalidomide and dexamethasone (IRd), we conducted an indirect comparison of the efficacy of IRd relative to several RRMM therapies using Bayesian fixed-effects network meta-analysis (NMA) models.

METHODS

Data for the NMA were obtained through a systematic literature review (conducted in June 2020), which identified randomized controlled trials (base case) and observational studies (extended network analysis) reporting overall survival (OS), progression-free survival (PFS), and overall response rate (ORR).

RESULTS

In the base case, IRd was associated with a significantly longer PFS than lenalidomide and dexamethasone (Rd), bortezomib monotherapy (V), dexamethasone (Dex), and pomalidomide and dexamethasone (Pom-dex), a significantly shorter PFS than daratumumab, lenalidomide, and dexamethasone (DRd), and a PFS comparable to elotuzumab, lenalidomide, and dexamethasone (ERd) and carfilzomib, lenalidomide, and dexamethasone (KRd). IRd was associated with a significantly longer OS than V, Dex, and Pom-dex, and an OS comparable to Rd, ERd, KRd, and DRd. The ORR of IRd was significantly higher than Rd, V, and Dex, significantly lower than KRd and DRd, and comparable to Pom-dex and ERd. The extended network analyses and sensitivity analyses were consistent with the base case.

DISCUSSION

This NMA shows that IRd is relatively efficacious among RRMM treatments. Being an oral regimen, IRd is also convenient to manage.

CONCLUSION

IRd could be a preferable treatment option for many patients with RRMM, particularly those seeking an efficacious and convenient therapeutic option.

Increasing transparency in indirect treatment comparisons: is selecting effect modifiers the missing part of the puzzle? A review of methodological approaches and critical considerations

Failure to adjust for effect modifiers (EMs) in indirect treatment comparisons (ITCs) can produce biased and uncertain effect estimates. This is particularly important for health technology assessments (HTAs), where the availability of new treatments is based on comparative effectiveness results. Much emphasis has been placed on advancing ITC methods to adjust for EMs, yet whether EMs are appropriately identified for the conduct of ITCs in the first place is unclear. To understand the extent of guidance and requirements for the selection of EMs for ITCs currently available and if and how this guidance is applied in practice, a series of pragmatic reviews of guidance documents from HTA and non-payer organizations, primary published ITC analyses, and prior HTA submissions in two indications (non-small cell lung cancer and psoriasis) was conducted. The reviews showed that current ITC guidance mainly focused on developing analytical methods to adjust for EMs. Some organizations, such as HTA bodies in the UK, France and Germany, recommended the use of literature reviews, expert opinion and statistical methods to identify EMs. No detailed guidance on the selection process or the appropriate literature review approach was found. Similar trends were identified through the database search and review of prior HTA submissions; only few published ITCs and submissions included information on the EM selection process which was either based on findings from the literature, trial subgroup analyses, or clinical input. No reference to a systematic selection approach was found. There is an urgent need to fill the guidance gap identified across the reviews by including a step in ITC guidelines on how EMs should be identified through systematic reviews, formal expert elicitation, and a quantitative assessment of the EM distribution. Researchers and manufacturers are also encouraged to improve transparent reporting and justification of their selection of EMs to allow for an independent review of the set of factors being considered for adjustment. Both will contribute toward reducing bias in the ITC results and ultimately increase confidence in decision-making.

Effect modification in network meta-analyses for relapsed/refractory multiple myeloma: systematic review and meta-analysis

OBJECTIVES

To systematically review and meta-analyse the evidence for effect modification by refractory status and number of treatment lines in relapsed/refractory multiple myeloma (RRMM); and to assess whether effect modification is likely to invalidate network meta-analyses (NMA) that assume negligible modification.

DESIGN

Systematic review, meta-analysis and simulation.

DATA SOURCES

We systematically searched the literature (e.g., OVID Medline) to identify eligible publications in February 2020 and regularly updated the search until January 2022. We also contacted project stakeholders (including industry) ELIGIBILITY CRITERIA: Phase 2 and 3 randomised controlled trials reporting stratified estimates for comparisons with at least one of a prespecified set of treatments relevant for use in Norwegian RRMM patients.

OUTCOMES

We used meta-analysis to estimate relative HRs (RHRs) for overall survival (OS) and progression-free survival (PFS) with respect to refractory status and number of treatment lines. We used the estimated RHRs in simulations to estimate the percentage of NMA results expected to differ significantly in the presence versus absence of effect modification.

RESULTS

Among the 42 included publications, stratified estimates were published by and extracted from up to 18 (43%) publications and on as many as 8364 patients. Within-study evidence for effect modification is very weak (p>0.05 for 47 of 49 sets of stratified estimates). The largest RHR estimated was 1.32 (95% CI 1.18 to 1.49) for the modifying effect of refractory status on HR for PFS. Simulations suggest that, in the worst case, this would result in only 4.48% (95% CI 4.42% to 4.54%) of NMA estimates differing statistically significantly in the presence versus absence of effect modification.

CONCLUSIONS

Based on the available evidence, effect modification appears to be sufficiently small that it can be neglected in adequately performed NMAs. NMAs can probably be relied on to provide estimates of HRs for OS and PFS in RRMM, subject to caveats discussed herein.

Matching-adjusted indirect comparison (MAIC) results confirmed by head-to-head trials: a case study in psoriasis

BACKGROUND

Head-to-head comparisons through randomized controlled trials (RCTs) provide high-quality evidence to inform healthcare decisions. In their absence, indirect comparisons are often performed; however, evidence is limited on how valid matching-adjusted indirect comparison (MAIC)-based comparative efficacy estimates are vs. RCT-based estimates.

OBJECTIVES

Compare MAIC and RCT results of guselkumab vs. secukinumab and ixekizumab to provide insight into validity of results generated using MAIC methods.

METHODS

Previously reported results from MAICs of guselkumab vs. secukinumab and ixekizumab were compared with results from ECLIPSE and IXORA-R RCTs based on risk differences between Psoriasis Area and Severity Index (PASI) 90 response rates.

RESULTS

Risk difference (95% confidence interval) in PASI 90 response rates at week 48 for guselkumab vs. secukinumab was 14.4% (9.4%; 19.4%) in ECLIPSE and 9.4% (4.7%; 14.0%) in the MAIC. The risk difference at week 24 for guselkumab vs. ixekizumab was 0.0% (-5.4%; 5.4%) in IXORA-R and 0.7% (-5.1%; 6.4%) in the MAIC.

CONCLUSIONS

Comparative efficacy results were consistent between MAICs and RCTs of guselkumab vs. secukinumab and ixekizumab. This analysis demonstrates that MAIC methods can provide valid relative treatment effect estimates when direct comparisons are lacking, particularly when trials with similar designs and patient populations inform the analysis.

Indirect treatment comparison of idecabtagene vicleucel versus conventional care in triple-class exposed multiple myeloma

Aim: To compare the efficacy of idecabtagene vicleucel (ide-cel, bb2121) versus conventional care (CC) in triple-class exposed relapsed and refractory multiple myeloma (RRMM) patients. Patients & methods: A matching-adjusted indirect comparison was conducted using individual patient-level data from the pivotal, phase II, single-arm KarMMa trial (NCT03361748) and aggregate-level data from MAMMOTH, the largest independent observational study of CC in heavily pretreated RRMM patients. Results: Ide-cel improved overall response rate (odds ratio: 5.30; 95% CI: 2.96-9.51), progression-free survival (hazard ratio: 0.50; 95% CI: 0.36-0.70) and overall survival (hazard ratio: 0.37; 95% CI: 0.25-0.56) versus CC. Conclusion: These results suggest ide-cel offers improvements in clinical outcomes relative to CC in this heavily pretreated RRMM population.

Network meta-analyses in psoriasis: overview and critical discussion

Network meta-analyses (NMAs) increasingly assist in treatment decisions in disease areas such as psoriasis, where data from multiple clinical trials (CTs) on a growing number of different drugs become available. This study aimed to characterize NMAs published in psoriasis. A systematic literature search in PubMed was conducted using a structured search protocol based on the PRISMA criteria. Twenty-seven NMAs were identified, including an average of 43 CTs per NMA. Only eight of 27 NMAs (29.6%) were documented in the PROSPERO registry and only 17 (63%) reported following the PRISMA criteria. The mean number of patients per NMA was 19 624 (range: 6113-51 749). Across all NMAs, the drugs most frequently included were ustekinumab (n = 27 NMAs), followed by adalimumab (n = 25), infliximab and etanercept (n = 24 each). In all n = 27 NMAs, placebo comparisons and in n = 25, comparisons with active controls were used for bridging. Effect estimates were performed in all cases, SUCRA in 14. Most frequently used outcomes were Psoriasis Area and Severity Index (PASI) 75 (n = 25) and PASI 90 (n = 24), and Dermatology Life Quality Index (n = 10). NMAs mostly measured induction efficacy (weeks 10-16, n = 25) but rarely long-term outcomes (weeks 48-56, n = 4). Sensitivity analyses were performed in n = 17 (63%) of the studies. Main results varied considerably between studies and depended on the year of publication and thus the number of available drugs and studies. However, the concordance between NMA efficacy rankings based on PASI 75 was high. Although a large number of NMAs have been published on psoriasis showing highly comparable results on efficacy, no sufficient information on the quality criteria was reported, and PROSPERO registry criteria were not followed. This argues in favour of greater standardization of NMA methodology and reporting.

Matching adjusted indirect comparisons of efficacy outcomes for idecabtagene vicleucel (ide-cel, bb2121) versus selinexor + dexamethasone and belantamab mafodotin in relapsed and refractory multiple myeloma

Idecabtagene vicleucel (ide-cel, bb2121), a chimeric antigen receptor (CAR) T cell therapy, has been investigated in patients with relapsed and refractory multiple myeloma (RRMM) who have received an immunomodulatory drug, proteasome inhibitor, and anti-CD38 antibody in the single-arm phase 2 KarMMa clinical trial. Two therapies with distinct mechanisms of action - selinexor plus dexamethasone (Sd) and belantamab mafodotin (BM) - are currently approved in the United States for heavily pretreated patients, including those who are triple-class refractory. To compare ide-cel versus Sd and ide-cel versus BM, matching-adjusted indirect comparisons were performed. Ide-cel extended progression-free survival (PFS) and overall survival (OS) versus both Sd and BM (hazard ratio (HR); 95% confidence interval (CI)). PFS: ide-cel versus Sd, 0.46; 0.28-0.75; ide-cel versus BM, 0.45; 0.27-0.77. OS: ide-cel versus Sd, 0.23; 0.13-0.42; ide-cel versus BM, 0.35; 0.14-0.87. These results suggest ide-cel offers clinically meaningful improvements over currently approved regimens for patients with heavily pretreated RRMM.