Search

Background: Pre-marketing authorisation estimates of survival are generally restricted to those observed directly in randomised controlled trials (RCTs). However, for regulatory and Health Technology Assessment (HTA) decision-making a longer time horizon is often required than is studied in RCTs. Therefore, extrapolation is required to estimate long-term treatment effect. Registry data can provide evidence to support extrapolation of treatment effects from RCTs, which are considered the main sources of evidence of effect for new drug applications. A number of methods are available to extrapolate survival data, such as Exponential, Weibull, Gompertz, log-logistic or log-normal parametric models. The different methods have varying functional forms and can result in different survival estimates. Methods: The aim of this paper was to use registry data to supplement the relatively short term RCT data to obtain long term estimates of effect. No formal hypotheses were tested. We explore the above parametric regression models as well as a nonparametric regression model based on local linear (parametric) regression. We also explore a Bayesian model constrained to the long term estimate of survival reported in literature, a Bayesian power prior approach on the variability observed from published literature, and a Bayesian Model Averaging (BMA) approach. The methods were applied to extrapolate overall survival of a RCT in metastatic melanoma. Results: The results showed that the BMA approach was able to fit the RCT data well, with the lowest variability of the area under the curve up to 72 months with or without the SEER Medicare registry. Conclusion: the BMA approach is a viable approach to extrapolate overall survival in the absence of long term data., 21 Pages, 7 named figures, 3 tables

Introduction: Multiple clinical studies in patients (pts) with newly diagnosed multiple myeloma (NDMM) have shown benefits from continuous lenalidomide (LEN) treatment (Tx), including extended progression-free survival (PFS), time to progression (TTP), and overall survival (OS) (Facon, Blood 2013; Palumbo, NEJM 2012). Dose modifications are commonly utilized by physicians as part of continuous Tx plans to sustain control of disease while managing toxicities. Previous analysis has shown that dose modification of LEN was associated with longer duration of therapy (DOT) relative to non-dose modification, in the real-world setting (Lang, Blood 2013). This study aimed to evaluate whether LEN dose modification is associated with a longer TTP in NDMM pts, utilizing time to next therapy (TTNT) as a proxy measure available from claims data. Methods: A retrospective study was conducted using a large US medical and pharmacy claims database, covering > 25 million lives annually. NDMM pts were identified with at least 2 outpatient claims or 1 inpatient medical claim associated with a diagnosis of MM (ICD-9-CM code 203.0X), with the first such claim used to define the index date. A minimum of 12 months' pre-index enrollment and 6 months' post-index continuous enrollment between Jan 1 2006 and December 31 2012 was required. The analysis focused on NDMM pts treated with LEN who did not have claims for stem cell transplantation (SCT), to avoid DOT limitations imposed by fixed-length induction Tx. Median DOT and TTNT were compared in NDMM pts with and without LEN dose modifications (dose increase or decrease). Charlson comorbidity scores were determined to compare baseline measures between the groups. Results: Of the 1,360 pts who met the inclusion criteria, 470 (35%) had LEN dose modifications, including 154 pts with at least one dose increase and 421 pts with at least one dose decrease. The majority of pts had an initial dose of 25mg. The median DOT was 447 days in pts with LEN dose modification and 182 days in those pts with no dose modification (p < 0.001). The median DOT in pts with dose modification was consistent regardless of whether they experienced a dose increase or decrease, with no significant difference. The median TTNT in pts with LEN dose modification was 3.5 yrs compared to 2.0 yrs in pts without dose modification (p < 0.001; Figure 1). Charlson comorbidity scores were similar in pts with and without LEN dose modification. Figure 1 Figure 1. Conclusions: For non-SCT NDMM patients treated with LEN, dose modifications during their treatment were associated with a doubling of the median therapy duration and a 71% longer median TNTT, compared to pts without LEN dose modification. The DOT and TTNT in pts with dose modification were similar to median values reported for the LEN continuous Tx arm of the FIRST clinical trial (Facon, Blood 2013). This analysis suggests that LEN dose modification in the Tx of NDMM may be an effective tool in the real-world setting for pts to achieve sustained disease Tx and the associated prolonged time to progression, based on the proxy measure of TTNT. Disclosures Usmani: Celgene Corporation: Consultancy, Honoraria, Research Funding; Millennium: Consultancy, Honoraria; Onyx: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy; Array BioPharma: Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding. Off Label Use: Lenalidomide in newly diagnosed multiple myeloma patients. Binder:Celgene Corporation: Employment, Equity Ownership. Milentijevic:Celgene Corporation: Consultancy. Hu:Celgene: Employment. Nagarwala:Celgene Corporation: Employment. Corvino:Genesis Research LLC: Consultancy. Arikian:Genesis Research: Consultancy. Surinach:Genesis Research LLC: Consultancy. Harwin:Celgene Corporation: Honoraria.