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Objective: To evaluate cost-effectiveness of brentuximab vedotin in patients with relapsed/refractory Hodgkin lymphoma who have received autologous stem cell transplantation, from a Scottish healthcare payer perspective. Methods: A Microsoft Excel-based partitioned survival model comprising three health states (progression-free survival [PFS], post-progression survival, and death) was developed. Relevant comparators were chemotherapy with or without radiotherapy (C/R) and C/R with intent to allogeneic hematopoietic stem cell transplantation (alloSCT). Data were obtained from the pivotal phase II single-arm trial in 102 patients (SG035-0003; NCT00848926), a systematic literature review and clinical expert opinions (where empirical evidence was unavailable). PFS and overall survival for brentuximab vedotin were estimated using 5-year follow-up data from SG035-0003, and extrapolated using event rates observed for comparator treatments from published survival data. Resource use included drug acquisition and administration; alloSCT; treatment of adverse events; and long-term follow-up. Deterministic and probabilistic sensitivity analyses were conducted to evaluate the impact of uncertainty. Results: In the base case, the incremental cost-effectiveness ratio (ICER) for brentuximab vedotin was £38,769 per quality-adjusted life year (QALY) vs C/R, whereas C/R with intent to alloSCT was dominated by brentuximab vedotin. ICERs for brentuximab vedotin generated by the deterministic sensitivity analysis ranged between £32,000–£54,000 per QALY. Including productivity benefits reduced the ICER to £28,881 per QALY. Limitations: Limitations include lack of comparative data from this single arm study and the heterogeneous population. Inconsistent baseline characteristic reporting across studies prevented complete assessment of heterogeneity and the extent of potential bias in clinical and cost-effectiveness estimates. Conclusions: Although the base case ICER is above the threshold usually applied in Scotland, it is relatively low compared with other orphan drugs, and lower than the ICER generated using a previous data cut of SG035-0003 that informed a positive recommendation from the Scottish Medicines Consortium, under its decision-making framework for assessment of ultra-orphan medicines.

Background Clinical trials for treatments indicated for orphan diseases may be limited due to the low prevalence of such diseases; this can result in implications for both regulatory and health economic perspectives. This study assessed the pivotal clinical evidence packages submitted to support applications for European Medicines Agency (EMA) marketing authorizations for treatments for orphan conditions, in relation to the size of the eligible patient population. Methods Approved treatments for EMA-designated orphan conditions (defined as life-threatening or chronically debilitating conditions that affect ≤5/10,000 people) were identified from the EMA web site. All treatments reviewed were included in anatomical therapeutic chemical (ATC) category L (antineoplastic and immunomodulating drugs): this category was selected because it is the largest ATC category, containing almost 50 % of all approved orphan-designated products. Treatments were reviewed if they had been approved within the past 7 years and had been evaluated in a controlled trial using at least one survival-based clinical endpoint. Treatments were compared in terms of patient-years (accumulated duration of follow-up), the number of patients in the pivotal trials and disease prevalence. Results As of 1 February 2014, 68 treatments had been approved for orphan-designated conditions, of which 30 belonged to ATC category L and 14 met all inclusion criteria. The number of patients in the pivotal trials ranged from 162 to 846 (median 485). In terms of patient-years, the longest duration of follow-up was seen in the pivotal trial of mifamurtide in osteosarcoma, which had 4068 patient-years; excluding this trial, follow-up ranged from 308 to 2906 patient-years (median 1796 years). Osteosarcoma had the second smallest eligible patient population (0.5/10,000 persons) of the reviewed treatments. Conclusions Clinical trials of orphan treatments are often limited by low patient numbers and inadequate follow-up. Pooling of expertise in single centres and the establishment of rare disease reference networks and patient registries may facilitate appropriate trial design for orphan-designated treatments. This analysis found that the pivotal clinical trial for mifamurtide in osteosarcoma had the largest number of patient-years of follow-up, despite a small eligible patient population, showing that it is possible to conduct studies with an adequate patient population size and duration of follow-up in patient-years, and a comparative design with clinical, survival-based, endpoints.

19 Background: In 2015, the Scottish Medicines Consortium (SMC) made a positive recommandation for brentuximab vedotin (BV) in patients with relapsed or refractory (R/R) Hodgkin lymphoma (HL) who have received autologous stem cell transplantation (ASCT) based on 3-year follow-up data from the pivotal phase 2 single-arm trial (SG035-0003; NCT00848926). At 3-years, the incremental cost-effectiveness ratio (ICER) for brentuximab vedotin compared with chemotherapy +/- radiotherapy (C/R) was £43,731 per quality-adjusted life year (QALY). This study re-evaluated the cost-effectiveness analysis with 5-year follow-up data from the pivotal trial. Methods: A partitioned survival model was developed using a Scottish health system perspective over a lifetime time-horizon. Three health states were evaluated: progression-free survival (PFS), post-progression survival, and death. The relevant comparators were C/R, or C/R with intent to allogeneic stem cell transplantation. Clinical outcomes (PFS and overall survival [OS]) for BV were estimated based on data from the pivotal trial in 102 patients. A naïve comparison with the specified comparators was conducted using published survival data. ICERs were calculated with measures of the clinical outcomes, direct costs and QALYs. Deterministic and probabilistic sensitivity analyses were conducted to evaluate the robustness of the model. Results: The 5-year follow-up data reduced the base case ICER for BV from £43,731 to £38,769 per QALY versus C/R and increased the probability of cost-effectiveness. The variation in ICER for BV generated by the deterministic sensitivity analyses was also reduced resulting from reduced uncertainty in the estimation of long term clinical outcomes. Conclusions: This update has strengthened the cost-effectiveness evidence for BV in patients with R/R HL post-ASCT. The 5-year follow-up has reduced the uncertainty in the long term outcomes and reduced the ICER, which is low in comparison to other treatments for orphan diseases approved by UK agencies. BV may therefore represent a cost-effective treatment option for this patient group.

18 Background: Systemic anaplastic large cell lymphoma (sALCL) is a rare T-cell lymphoma. For patients who fail front-line therapy, outcomes are poor and there is no current defined standard of care. Brentuximab vedotin has demonstrated high objective response rates and is approved for patients with relapsed or refractory (R/R) sALCL. However, the cost-effectiveness of brentuximab vedotin compared with conventional chemotherapy has not been explored. Methods: A lifetime Excel-based partitioned survival model was used to compare survival outcomes from the pivotal phase-2 single-arm brentuximab vedotin trial of 58 R/R sALCL patients with good Eastern Corporative Oncology Group (ECOG) performance status after one or more prior therapies (SG035-0004); with 40 sALCL patients from a Canadian cancer registry receiving first-line conventional salvage chemotherapy (65% with ECOG 0 or 1) between 1980 and 2012 and followed for up to 20 years. Extrapolation of brentuximab vedotin survival after the trial period assumed the same rate of change as for conventional chemotherapy. A United Kingdom National Health Service perspective was adopted. Costs included drug acquisition and administration, and medical care for adverse events and pre- and post-progression. Utility values elicited by response and by progression, and disutilities associated with adverse events were applied to estimate quality-adjusted life years (QALYs). Results: The incremental cost-effectiveness ratio (ICER) for brentuximab vedotin was £35,390 per QALY gained versus conventional chemotherapy. ICERs were between £28,112 and £61,921 across a range of alternative model assumptions. Comparing only first-line salvage patients in both groups reduced the ICER to £26,766. Conversely, considering only patients with good ECOG performance status increased the ICER to £38,186. Using probabilistic sensitivity analysis, at willingness-to-pay of £38,000, the probability that brentuximab vedotin is cost-effective was > 50%. Conclusions: Brentuximab vedotin may represent a cost-effective intervention compared to conventional chemotherapy for this patient population with limited therapeutic options.

Aim: Conducting large, well-designed clinical trials for treatments indicated for orphan diseases presents certain challenges, including the low prevalence of such diseases. This study assessed the pivotal clinical evidence package presented in the European public assessment report for orphan-designated treatments with a European Medicines Agency (EMA) marketing authorisation. The evidence packages were compared in terms of the size of patient population in relation to the prevalence of the indicated orphan disease. Methods: All treatments reviewed in this study are assigned to anatomical therapeutic chemical (ATC) category ‘L’. This category was focused on because it is the largest ATC category (contains almost 50% of orphan-designated products) and includes all EMA-approved orphan oncology treatments. All treatments reviewed have been approved within the past 6 years and have been evaluated in a controlled trial using at least one survival-based clinical endpoint. Treatments were compared in terms of patient years (accumulated amount of time that patients are followed up), number of patients in the pivotal trial(s), and disease prevalence (information from Committee for Orphan Medicinal Products public summary of opinion). Results: Fourteen treatments fulfilled the inclusion criteria. Mifamurtide (Mepact®) was an outlier with 4,068 patient years; excluding mifamurtide, patient years ranged from 308 to 2,906 years (median 1,796 years). Mifamurtide was also found to have the second smallest eligible patient population (0.5/10,000 persons). The number of patients in the pivotal trial(s) ranged from 162 to 846 patients (median 485 patients); there were 678 patients in the mifamurtide pivotal trial. Conclusions: The low prevalence of orphan diseases often results in trials with low patient numbers and low patient years. The pivotal evidence package for mifamurtide (indicated for the orphan disease osteosarcoma) has both a small eligible patient population and the largest number of patient years. This study provides support for the robustness of the pivotal evidence package for mifamurtide. Disclosure: J.M. Winstone, S. Chadda and S. Ralston: PHMR Associates has received funding from Takeda to conduct the research; P. Sajosi: Peter Sajosi is an employee of Takeda.