Major Depressive Disorder (MDD) is one of the most burdensome illnesses globally, with significant negative impacts on activities of daily living, quality of life, cognitive function, and employment status and work productivity [1,2]. Researchers studying MDD are challenged by the complex nature of the disease, which is often comorbid with other chronic and acute conditions, including both physical and psychiatric disorders. In particular, the treatment pathway for patients with MDD is remarkably complicated, with extensive variability in disease presentation, uncertainty of diagnoses, and heterogeneity of treatment effects.The research featured in this special issue of Pharma-coEconomics draws on findings from a variety of countries across North America, Europe, Asia, and Oceania. Although differences in culture as well as health and social care systems complicate research in MDD, a broad survey of studies of the burden of MDD provides an opportunity for new insights concerning the many determinants of health outcomes associated with this disease. This editorial overview surveys these studies, focusing on several unifying themes:1. Growing prevalence of MDD, particularly during the coronavirus disease 2019 (COVID-19) pandemic 2. Research concerning the cost of MDD 3. Economic burden of MDD in subpopulations 4. Advances in analytical methods 5. Implications for researchers and policy makers.

Sickle cell disease (SCD) patients are at high risk of central nervous system (CNS) complications and may experience significant morbidity. The study was conducted to describe the comprehensive burden of SCD‐related CNS complications and to identify patient‐reported outcome (PRO) instruments for future research. The review included 32 studies published from January 2000 to 2020, evaluating humanistic and economic outcomes. Twenty‐three studies reported humanistic outcomes, 16 of which measured cognitive function using Wechsler Intelligence Scales. A meta‐analysis was conducted, finding full‐scale intelligence quotient (IQ) was significantly lower in: overt stroke versus controls: −12.6 (p < .001); silent cerebral infarct (SCI) versus controls: −5.7 (p < .001); overt stroke versus SCI: −9.4 (p = .008); and any event versus controls: −7.6 (p < .001). This review quantified the cognitive deficits associated with CNS complications in pediatric SCD populations and highlights the need for improved prevention/treatment. As PRO evidence was limited, we discussed areas for future research.

Introduction: Tazemetostat is an enhancer of zeste homolog 2 (EZH2) inhibitor recommended for patients with relapsed/refractory (R/ R) follicular lymphoma (FL) after demonstrating single-agent, antitumor activity in patients with wild-type or mutant EZH2. The phosphoinositide 3-kinase (PI3K) inhibitors idelalisib, copanlisib, umbralisib and (formerly) duvelisib are indicated for third-line, fourth-line, and later (3L/4L?) treatment of R/R FL. The objective of this analysis was to provide an indirect treatment comparison of tazemetostat with each PI3K inhibitor for 3L/4L? R/R FL treatment. Methods: A systematic literature review was conducted to identify trials for idelalisib (DELTA), duvelisib (DYNAMO), copanlisib (CHRONOS-1 Part B), and umbralisib (UNITY-NHL