Patient Perceptions Of Treatments In SCD: Implications For Gene Transfer Therapy
Authors: Crosby Lori E , Mitchell Monica J , Strong Heather , Shook Lisa , Hines Janelle , Nordheim Tammy , McCuistian Caravella L , Malik Punam 
Published: October 2019

Abstract
Sickle cell disease (SCD) is a chronic genetic disease with high morbidity and early mortality affecting approximately 100,000 individuals in the US.Treatment of SCD has primarily focused on symptom management and infection prevention; however, there are two targeted therapeutic options: bone marrow transplant (BMT) and hydroxyurea (HU). BMT is curative, but limited by matched donor siblings and immunological risks. Barriers to acceptance of BMT from a matched donor are not well understood. HU if taken on a long term basis, reactivates fetal hemoglobin (HbF), reduces sickling, and prolongs survival but may be associated with side-effects related to marrow suppression. Additionally, adherence is a major compliance barrier to daily life-long HU use. Gene transfer therapy (GTT) is a novel, potential treatment for SCD. GTT is a one-time treatment that transfers an anti-sickling gene (e.g. gamma globin/HbF producing gene) into bone marrow hematopoietic stem cells. These cells can then produce sickling resistant RBCs. Little is known about the knowledge, beliefs, and acceptance of GTT and other SCD treatments in adults with SCD. If we are to improve outcomes in SCD, it is essential that we provide developmentally and culturally appropriate disease education that integrates patients’ values and supports informed decision-making.The aims of the current study were to assess: 1) perceptions and knowledge about treatments in adults with SCD, and 2) the effectiveness of GTT educational materials. To the best of our knowledge, this is the first study to examine the perceptions of GTT in SCD.

Methods
Participants from two cohorts (ages 18-30 and ages 30-45) participated in focus groups and completed measures including a demographics survey (e.g. age, gender, medical history), the Patient-Reported Outcomes Measurement Information System (PROMIS) Global Health-Related Quality of Life survey (HRQOL), and a focus group questionnaire (e.g. disease knowledge /perceptions, evaluation of education materials). The HRQOL survey assessed both physical and mental health status. Qualitative data was analyzed using evidence-based methods, organizing responses into broad conceptual categories. Descriptive analyses and a linear regression were used to analyze quantitative data.

Results
Twenty-six adults with HbSS (88%), HbSC (4%), or HbSB+Thal (8%) participated in one of two focus groups. Cohort 1 (N= 14, 50% male) had a mean age of 21.7 (SD= 2.7) and Cohort 2 (N= 12, 45.5% male) had a mean age of 42.8 (SD= 12.2). With respect to disease severity (mild, moderate, or severe), 40% of Cohort 1 reported mild severity and 55% of Cohort 2 reported severe severity. The groups did not differ on their HRQOL scores. HU was the most recognized treatment (Cohort 1= 89%; Cohort 2= 91%). Participants were less aware of BMT (Cohort 1= 56%; Cohort 2= 70%) and least aware of GTT (Cohort 1= 38%; Cohort 2= 56%). Participants were asked their perception of treatments on a scale of 0-negative to 10-positive. HU was rated most favorably (Cohort 1, M=6.5, SD= 3.0; Cohort 2, M= 8.8, SD= 1.7). BMT was rated less favorably (Cohort 1, M= 4.1, SD= 3.4; Cohort 2, M= 5.8, SD= 4.3). Impressions of GTT were least favorable (Cohort 1, M= 2.8, SD= 2.3; Cohort 2, M= 5.4, SD= 4.0). A linear regression was used determine if treatment knowledge predicted treatment perception; a significant relationship was present only for BMT (ß= 5.1, p< .05). Clarity of educational materials was rated on a scale of 0-not at all to 10-very much. Cohort 2 rated the explanation of GTT (M=10, SD= 0) more positively than Cohort 1 (M=7.7, SD= 2.2). A thematic analysis of focus group discussions highlighted barriers to HU, BMT, and GTT and recommendations for improving educational materials.

Conclusions
This study provides insight regarding SCD patients’ knowledge and perceptions about GTT and other treatments. Knowledge of BMT was associated with more positive perceptions of this treatment. Since this relationship was not present for HU, it may be that this association is important for more complex treatments, such as BMT and GTT. Study results highlight the importance of ensuring that GTT educational materials are clear, particularly for younger adults, and inform the development of educational and recruitment materials for SCD treatment research studies.
This study was supported in part by NIH CTSA Grant #: 8 UL1 TR000077-04, and the Cincinnati Comprehensive Sickle Cell Center.

Disclosures:
No relevant conflicts of interest to declare.