Polatuzumab vedotin-bendamustine-rituximab (PBR) versus tafasitamab-lenalidomide (TafaL) in ASCT-transplant ineligible relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL): Economic evaluation including novel metrics.

Abstract

e19535 Background: PBR and TafaL are two recently regulatory approved regimens that offer treatment options for R/R DLBCL patients who are ASCT ineligible or choose not to undergo ASCT. PBR is administered over 6 cycles, whereas TafaL is sustained until disease progression or death. We report here on an independent, naïve comparative, pharmacoeconomic evaluation of both regimens. Methods: Cost effectiveness and cost utility analyses were performed using a Markov model with 3 health states (progression free survival (PFS), post progression survival (PPS), death) parametrically extrapolated over a 5-year (y) time horizon (US payer perspective; 2020 USD). Cost inputs included main treatment, premedication, drug administration, adverse event management, and physician and laboratory fees. Incremental cost effectiveness ratios (ICER) and cost-utility ratios (ICUR) estimated the incremental costs to gain 1 unadjusted (LY) or quality adjusted life years (QALY), respectively. A novel metric of the incremental cost per 1% gain in probability of achieving objective response (OR), PFS and overall survival (OS) at trial follow up (̃2y) and PFS and OS at 5y with TafaL over PBR were estimated. Deterministic (DSA) and probabilistic (PSA) sensitivity analyses complemented base case analyses (BCA). Willingness to pay (WTP) thresholds were estimated. Results: At trial follow up (̃2y), PFS and OS rates were 38% and 63% for TafaL vs rates of 18% and 27.5% for PBR. The corresponding 5y PFS and OS rates were 13% and 32.7% for TafaL vs 5.2% and 11.3% for PBR. In BCAs, 5y TafaL costs ($470,949) exceeded PBR’s ($251,615) by $219,334 for incremental gains of 0.71 LY and 0.32 QALY. This yielded BCA ICER of $307,840/LYg and ICUR of $689,314/QALYg attenuated in PSA estimates of ICER of $280,042/LYg and ICUR of $589,215/QALYg. In DSAs, TafaL PFS utility value and PBR treatment costs were the most influential parameters. In PSAs, TafaL had a 50% probability of being cost effective at WTPs of $278,050/LYg and $560,360/QALYg. The incremental cost per 1% gain in probability to achieve OR, PFS and OS at follow up were $7,714, $5,785 and $3,259; and $28,120 and $10,249 for PFS and OS at 5 years. Conclusions: Considering that economic evaluations are intended to inform (but not set) policy, this independent analysis demonstrated that sustained TafaL treatment is associated with better survival outcomes than PBR though at greater cost. The incremental costs to gain a 1% improvement in 2y and 5y survival outcomes with TafaL over PBR were modest, underscoring the longer-term benefit of TafaL over PBR in pts ineligible for or opting out of ASCT.