The Lived Experience of Pediatric Gene Therapy: A Scoping Review

Little is known about patients' and families' lived experiences of participating in pediatric gene therapy (GT) clinical trials. Currently, pediatric GT research targets a broad range of indications--including rare and ultra-rare diseases--which vary in severity and in the availability of alternative therapies. Pediatric GT differs meaningfully from adult GT because the decision to participate involves a dyad of both the child and parent or caregiver/s. It is critical to understand patients' and caregivers' perceptions and experiences of social, emotional, physical, and logistical burdens or benefits of participating in such trials, and how they weigh and prioritize these factors when deciding whether to participate. We conducted a scoping review of the current literature in this subject area with objectives to (1) provide an overview of existing literature, (2) identify gaps and areas for further research, and (3) better understand the lived impact of pediatric GT research on patients and their parents/caregivers. Four themes emerged, including (1) weighing risks and benefits (2) timing of GT trial participation, (3) value of clear communication, and (4) potential impact on quality of life. Notably, our sample surfaced articles about how patients/parents/caregivers were thinking about GT-their understanding of its safety, efficacy, and risks-rather than accounts of their experiences, which was our initial intention. Nevertheless, our findings offer useful insights to improve the informed consent process and promote a more patient- and family-centered approach. Moreover, our findings can contribute to patient advocacy organizations' efforts to develop educational materials tailored to patients' and families' expressed informational needs and perspectives, and can inform more patient- and family-centered policies from GT clinical trial sponsors.

Development and electronic health record validation of an algorithm for identifying patients with Duchenne muscular dystrophy in US administrative claims

BACKGROUND: Muscular dystrophies (MDs) comprise a heterogenous group of genetically inherited conditions characterized by progressive muscle weakness and increasing disability. The lack of separate diagnosis codes for Duchenne MD (DMD) and Becker MD, 2 of the most common forms of MD, has limited the conduct of DMD-specific real-world studies. OBJECTIVE: To develop and validate administrative claims-based algorithms for identifying patients with DMD and capturing their nonambulatory and ventilation-dependent status. METHODS: This was a retrospective cohort study using the statistically deidentified Optum Market Clarity Database (including patient claims linked with electronic health records [EHRs] data) to develop and validate the following algorithms: DMD diagnosis, nonambulatory status, and ventilation-dependent status. The initial study sample consisted of US patients in the database who had a diagnosis code for Duchenne/Becker MD (DBMD) between October 1, 2018, and September 30, 2020, who were male, aged 40 years or younger on their first DBMD diagnosis, and met continuous enrollment and 1-day minimal clinical activities requirement in a 12-month measurement period between October 1, 2017, and September 30, 2020. The algorithms, developed by a cross-functional team of DMD specialists (including patient advocates), were based on administrative claims data with International Classification of Diseases, Tenth Revision, Clinical Modifications coding, using information of diagnosis codes for DBMD, sex, age, treatment, and disease severity (eg, evidence of ambulation assistance/support and/or evidence of ventilation support or dependence). Patients who met each algorithm and had EHR notes available were then validated against structured fields and unstructured provider notes from their own linked EHR to confirm patients' DMD diagnoses, nonambulatory status, and ventilation-dependent status. Algorithm performance was assessed by positive predictive value with 95% CIs. RESULTS: A total of 1,300 patients were included in the initial study sample. Of these, EHR were available and reviewed for 303 patients. The mean age of the 303 patients was 14.8 years, with 61.7% being non-Hispanic White. A majority had a Charlson comorbidity index score of 0 (59.4%) or 1-2 (27.7%). Positive predictive value (95% CI) was 91.6% (85.8%-95.6%) for the DMD diagnosis algorithm, 88.4% (80.2%-94.1%) for the nonambulatory status algorithm, and 77.8% (62.9%-88.8%) for the ventilation-dependent status algorithm. CONCLUSIONS: This work provides the means to more accurately identify patients with DMD from administrative claims data without a specific diagnosis code. The algorithms validated in this study can be applied to assess treatment effectiveness and other outcomes among patients with DMD treated in clinical practice. DISCLOSURES: This study was funded by Pfizer, which contracted with Optum to perform the study and provide medical writing assistance. Ms Schrader reports being an employee of Parent Project Muscular Dystrophy. Mr Posner reports being an employee and stockholder of Pfizer and receiving support from Pfizer for attending conferences not related to this manuscript. Dr Dorling reports being an employee and stockholder of Pfizer at the time the study was conducted and is a current employee of Chiesi USA, Inc. Ms Senerchia reports being an employee of Optum and owning stock in Pfizer and UnitedHealth Group, the parent company of Optum. Dr Chen reports being an employee and stockholder of Pfizer. Ms Beaverson reports being an employee of Pfizer and owning stock in Pfizer and Amicus Therapeutics. Dr Seare reports being an employee of Optum at the time the study was conducted. Dr Garnier and Ms Merla report being employees of Pfizer. Ms Walker reports being an employee of Optum. Dr Alvir reports being an employee and stockholder of Pfizer. Dr Mahn reports being an employee and stockholder of Pfizer. Dr Zhang reports being an employee of Optum. Ms Landis reports being an employee of Optum. Ms Buikema reports being an employee of Optum and holding stock in UnitedHealth Group, the parent company of Optum.

Key measurement concepts and appropriate clinical outcome assessments in pediatric achondroplasia clinical trials

BACKGROUND

This study aimed to identify fit-for-purpose clinical outcome assessments (COAs) to evaluate physical function, as well as social and emotional well-being in clinical trials enrolling a pediatric population with achondroplasia. Qualitative interviews lasting up to 90 min were conducted in the US with children/adolescents with achondroplasia and/or their caregivers. Interviews utilized concept elicitation methodology to explore experiences and priorities for treatment outcomes. Cognitive debriefing methodology explored relevance and understanding of selected COAs.

RESULTS

Interviews (N = 36) were conducted with caregivers of children age 0-2 years (n = 8) and 3-7 years (n = 7) and child/caregiver dyads with children age 8-11 years (n = 15) and 12-17 years (n = 6). Children/caregivers identified pain, short stature, impacts on physical functioning, and impacts on well-being (e.g. negative attention/comments) as key bothersome aspects of achondroplasia. Caregivers considered an increase in height (n = 9/14, 64%) and an improvement in limb proportion (n = 11/14, 71%) as successful treatment outcomes. The Childhood Health Assessment Questionnaire (CHAQ) and Quality of Life in Short Stature Youth (QoLISSY-Brief) were cognitively debriefed. CHAQ items evaluating activities, reaching, and hygiene were most relevant. QoLISSY-Brief items evaluating reaching, height bother, being treated differently, and height preventing doing things others could were most relevant. The CHAQ and QoLISSY-Brief instructions, item wording, response scales/options and recall period were well understood by caregivers and adolescents age 12-17. Some children aged 8-11 had difficulty reading, understanding, or required caregiver input. Feedback informed minor amendments to the CHAQ and the addition of a 7-day recall period to the QoLISSY-Brief. These amendments were subsequently reviewed and confirmed in N = 12 interviews with caregivers of children age 0-11 (n = 9) and adolescents age 12-17 (n = 3).

CONCLUSIONS

Achondroplasia impacts physical functioning and emotional/social well-being. An increase in height and improvement in limb proportion are considered to be important treatment outcomes, but children/adolescents and their caregivers expect that a successful treatment should also improve important functional outcomes such as reach. The CHAQ (adapted for achondroplasia) and QoLISSY-Brief are relevant and appropriate measures of physical function and emotional/social well-being for pediatric achondroplasia trials; patient-report is recommended for age 12-17 years and caregiver-report is recommended for age 0-11 years.

Patients' and caregivers' maximum acceptable risk of death for non-curative gene therapy to treat Duchenne muscular dystrophy

BACKGROUND

Gene therapy offers an etiologically targeted treatment for genetic disorders. Little is known about the acceptance of mortality risk among patients with progressive, fatal conditions. We assessed patients' and caregivers' maximum acceptable risk (MAR) of mortality for gene therapy when used to treat Duchenne muscular dystrophy (DMD).

METHODS

The threshold technique was used to assess tolerance for mortality risks using a hypothetical vignette. Gene therapy was described as non-curative and resulting in a slowing of progression and with a 10-year benefit duration. MAR was analyzed using interval regression for gene therapy initiated "now"; in the last year of walking well; in the last year of being able to bring arms to mouth; and in newborns (for caregivers only).

RESULTS

Two hundred eighty-five caregivers and 35 patients reported the greatest MAR for gene therapy initiated in last year of being able to lift arms (mean MAR 6.3%), followed by last year of walking well (mean MAR 4.4%), when used "now" (mean MAR 3.5%), and when used in the newborn period (mean MAR 2.1%, caregivers only). About 35% would accept ≥200/2000 risk in the last year of being able to lift arms. Non-ambulatory status predicted accepting 1.8 additional points in MAR "now" compared with ambulatory status (p = 0.010). Respondent type (caregiver or patient) did not predict MAR.

CONCLUSION

In this first quantitative study to assess MAR associated with first-generation DMD gene therapy, we find relatively high tolerance for mortality risk in response to a non-curative treatment scenario. Risk tolerance increased with disease progression. Patients and caregivers did not have significantly different MAR. These results have implications for protocol development and shared decision making.

The evolving role of patient preference studies in health-care decision-making, from clinical drug development to clinical care management

Introduction: There is a growing trend of using patient preference studies to help incorporate the patient perspective into clinical drug development, care management, and health-care decision-making. Collecting and interpreting patient preference data is integral to multi-stakeholder engagement, patient-centric drug development, and clinical care management. Operationally, challenges exist in understanding 'when' and 'how' to embark on patient preference studies. This review will provide a brief overview of stated-preference methods, discuss applications throughout the clinical drug development and care management, and highlight how preference studies serve as a powerful tool for quantifying patient experiences for better outcomes. Areas covered: We present case studies to complement the different applications of stated-preference methods in clinical drug development and care management. We discuss the applications of preference data to help inform evidence-based patient advocacy, clinical development strategy, operational feasibility, regulator benefit-risk assessments, health technology assessments, and clinical decision-making. Expert commentary: Patient preference studies can serve as a powerful tool to engage patients and their communities as well as quantify the patient voice across different stages of clinical drug development and care management to support patient-centric health-care decision-making. It is expected that the application of these strategies will quickly advance in the coming years.

Priorities when deciding on participation in early-phase gene therapy trials for Duchenne muscular dystrophy: a best-worst scaling experiment in caregivers and adult patients

PURPOSE

Several gene therapy trials for Duchenne muscular dystrophy initiated in 2018. Trial decision making is complicated by non-curative, time-limited benefits; the progressive, fatal course; and high unmet needs. Here, caregivers and patients prioritize factors influencing decision making regarding participation in early-phase gene therapy trials.

METHODS

We conducted a best-worst scaling experiment among U.S. caregivers and adults with Duchenne (N = 274). Participants completed 11 choice sets, choosing features they cared about most and least when deciding whether to participate in a hypothetical gene therapy trial. We analyzed the data using sequential conditional logistic regression.

RESULTS

Participants prioritized improved muscle function in trial decision making. Concerns about participation limiting later use of gene transfer and editing were also important, as were improved lung and heart function. Low risk of death fell near the middle. Participants cared least about muscle biopsies and potential for randomization to placebo. Adults with Duchenne and caregivers of non-ambulatory children significantly prioritized improved lung function compared to caregivers of ambulatory children.

CONCLUSION

Our data demonstrate prioritization of anticipated benefits and opportunity costs relative to potential harms and procedures in gene therapy trial decision making. Such data inform protocol development, education and advocacy efforts, and informed consent.

Gene therapy as a potential therapeutic option for Duchenne muscular dystrophy: A qualitative preference study of patients and parents

Objectives

Duchenne muscular dystrophy (DMD) is a rare neuromuscular disorder that causes progressive weakness and early death. Gene therapy is an area of new therapeutic development. This qualitative study explored factors influencing parents’ and adult patients’ preferences about gene therapy.

Methods

We report qualitative data from 17 parents of children with DMD and 6 adult patients. Participants responded to a hypothetical gene therapy vignette with features including non-curative stabilizing benefits to muscle, cardiac and pulmonary function; a treatment-related risk of death; and one-time dosing with time-limited benefit of 8–10 years. We used NVivo 11 to code responses and conduct thematic analyses.

Results

All participants placed high value on benefits to skeletal muscle, cardiac, and pulmonary functioning, with the relative importance of cardiac and pulmonary function increasing with disease progression. More than half tolerated a hypothetical 1% risk of death when balanced against Duchenne progression and limited treatment options. Risk tolerance increased at later stages. Participants perceived a ‘right time’ to initiate gene therapy. Most preferred to wait until a highly-valued function was about to be lost.

Conclusion

Participants demonstrated a complex weighing of potential benefits against harms and the inevitable decline of untreated Duchenne. Disease progression increased risk tolerance as participants perceived fewer treatment options and placed greater value on maintaining remaining function. In the context of a one-time treatment like gene therapy, our finding that preferences about timing of initiation are influenced by disease state suggest the importance of assessing ‘lifetime’ preferences across the full spectrum of disease progression.

Risk factors for extraocular relapse following enucleation after failure of chemoreduction in retinoblastoma

OBJECTIVE

To assess the outcome and determine risk factors for extraocular relapse in patients with retinoblastoma who had been enucleated after failure of chemoreduction.

METHODS

Retrospective study (1995-2002) at three institutions. Pathological risk factors (PRF) were defined as invasion of the anterior segment, choroid, post-laminar optic nerve, subarachnoid space, or sclera according to the local pathology report. Extraocular relapse was defined as an event.

RESULTS

One hundred twenty-two patients were included (17 had bilateral enucleation). Chemoreduction included vincristine, carboplatin, and etoposide (n=80, 65.6%), vincristine, and carboplatin (n=17, 13.9%), or carboplatin (n=25, 20.5%). Thirty-five also received external beam radiotherapy (28.7%). PRF included: 39 with choroidal involvement, 9 with anterior segment, 9 with scleral, and 2 with post-laminar optic nerve with subarachnoid invasion. Adjuvant chemotherapy was given to eight patients (6.5%) because of scleral invasion. Four patients had an extraocular relapse after enucleation, two of whom survive after intensive treatment including stem cell rescue. Five-year probability of event-free survival is 0.96. Only scleral invasion and bilateral enucleation were significantly associated with extraocular relapse.

CONCLUSIONS

The risk of extraocular relapse is low after enucleation following failure of chemoreduction. Patients who underwent bilateral enucleation and those with scleral invasion are at higher risk of extraocular relapse.

Fruit and Vegetable Intake during Pregnancy and Risk for Development of Sporadic Retinoblastoma

OBJECTIVE

Little is known about the causes of sporadic (noninherited) retinoblastoma. Rates seem to be somewhat higher among poorer populations in Mexico. Fruits and vegetables are important sources of carotenoids and folate. We examined whether decreased gestational maternal intake of fruits and vegetables may contribute to development of sporadic retinoblastoma.

METHODS

At the Instituto Nacional de Pediatria in Mexico City, we conducted a hospital-based case-control study to evaluate prenatal maternal diet. We examined dietary intake of fruits and vegetables of mothers of 101 children with retinoblastoma and 172 control children using a dietary recall questionnaire and published food nutrient content tables.

RESULTS

The reported number of mean daily servings of fruits and vegetables was lower among case mothers when compared with control mothers [vegetables: 2.28 in controls, 1.75 in cases (P < 0.01); fruits: 2.13 in controls, 1.59 in cases (P = 0.07)]. Mean daily maternal folate intake from both vegetables and fruits was higher in controls (103 microg) than in cases (48 microg; P < 0.05). Risk for having a child with retinoblastoma was increased for mothers consuming fewer than 2 daily servings of vegetables [odds ratios (OR), 3.4; 95% confidence interval (95% CI), 2.0-6.0] or with a low intake of folate (OR, 3.9; 95% CI, 2.1, 7.3), or lutein/zeaxanthin (OR, 2.6; 95% CI, 1.5-4.6) derived from fruits and vegetables.

CONCLUSIONS

Decreased intake of vegetables and fruits during pregnancy and the consequent decreased intake of nutrients such as folate and lutein/zeaxanthin, necessary for DNA methylation, synthesis, and retinal function, may increase risk for having a child with sporadic retinoblastoma.

Preimplantation genetic diagnosis for retinoblastoma: the first reported liveborn

PURPOSE

To develop an accurate mutation analysis procedure for retinoblastoma gene (RB1) mutation, which is sensitive at the single-cell level, and to use in vitro fertilization (IVF) and preimplantation genetic diagnosis (PGD) to achieve pregnancies without retinoblastoma.

DESIGN

Case report.

METHODS

Twelve day 3 embryos, obtained by IVF with intracytoplasmic sperm injection, underwent single-cell DNA testing via polymerase chain reaction and restriction enzyme analysis to detect the presence of a paternal RB1 mutation. Embryos were diagnosed as being unaffected and were transferred to the uterus on day 5.

MAIN OUTCOME MEASURES

Achieving a healthy pregnancy and delivery, assessed by clinical presentation, fundus photography, and RB1 molecular analysis.

RESULTS

A singleton pregnancy was achieved, and a child without retinoblastoma was born. The absence of the paternal RB1 mutation was confirmed on a sample of peripheral blood from the newborn.

CONCLUSIONS

We are first to report a successful human liveborn, delivered after IVF with preimplantation genetic diagnosis for retinoblastoma. The successful result indicates that preimplantation genetic diagnosis exists for this genetic disease and may represent a viable alternative to prenatal diagnosis with the subsequent option of terminating an affected pregnancy.

Screening for retinoblastoma: presenting signs as prognosticators of patient and ocular survival

OBJECTIVE

To correlate 3 common presenting signs of retinoblastoma with patient and ocular survival and to assess the efficacy of current pediatric screening practices for retinoblastoma.

METHODS

A retrospective study was conducted of 1831 retinoblastoma patients from our center (1914-June 2000). Patient survival (excluding deaths from other primary neoplasms) and ocular survival (presenting eyes) rates were calculated and analyzed using the Kaplan-Meier method.

RESULTS

Leukocoria correlated with excellent patient survival (>86%, 5 years) but poor ocular survival in unilateral (4%, 5 years) and bilateral patients (29%, 5 years). A total of 308 (19%) of 1654 patients presented with strabismus: patient survival was excellent (90%, 5 years), and ocular survival was poor (17%, 5 years) yet better than leukocoria. Patients who had a family history of retinoblastoma and were clinically screened for retinal tumors from birth were diagnosed younger (8 months of age) and earlier (Reese Ellsworth group 1 = 26 [58%] of 45) and had better ocular survival than nonscreened patients with a family history. More patients were initially detected by family/friends (1315 [80%] of 1632) than pediatricians (123 [8%] of 1632) or ophthalmologists (156 [10%] of 1632).

CONCLUSION

Most US children whose retinoblastoma is diagnosed initially present with leukocoria detected by a parent, despite routine pediatric screening for leukocoria via the red reflex test. Initial disease detection at the point of leukocoria or strabismus correlated with high patient survival rates and poor ocular survival rates for the presenting eye. Saving eyes and vision requires disease recognition before leukocoria, as demonstrated by the better ocular salvage rate among patients who had a positive family history and received clinical surveillance via early, routine dilated funduscopic examinations by an ophthalmologist.

New retinoblastoma tumor formation in children initially treated with systemic carboplatin

PURPOSE

To determine the frequency and timing of new intraocular tumor formation in children with hereditary retinoblastoma initially treated with systemic carboplatin.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

This study included 34 children (57 eyes) with hereditary bilateral retinoblastoma initially treated with systemic carboplatin at the Robert M. Ellsworth Ophthalmic Oncology Center at NewYork-Presbyterian Hospital from 1994 through 2000.

MAIN OUTCOME MEASURES

New tumor formation after initial treatment with systemic carboplatin.

RESULTS

There were a total of 165 tumors in 57 eyes. There were 63 new tumors in 27 eyes (47%) after administration of systemic carboplatin, for a mean of 1.1 new tumors per eye. The mean patient age at time of new tumor presentation was 9 months, with 57% of new tumors developing within 4 months of carboplatin treatment. Kaplan-Meier analysis showed that children who were treated when younger than 6 months of age were more likely to have new tumors (60%) compared with those treated after 6 months of age (31%; P = 0.0182).

CONCLUSIONS

New intraocular tumors continue to develop after systemic carboplatin; most new tumors appeared within 4 months of treatment.

Albers-Schönberg disease (autosomal dominant osteopetrosis, type II) results from mutations in the ClCN7 chloride channel gene

Albers-Schönberg disease, or autosomal dominant osteopetrosis, type II (ADO II), is the most common form of osteopetrosis, a group of conditions characterized by an increased skeletal mass due to impaired bone and cartilage resorption. Following the assignment of the gene causing ADO II to chromosome 16p13.3, we now report seven different mutations in the gene encoding the ClCN7 chloride channel in all 12 ADO II families analysed. Additionally, a patient with the severe, autosomal recessive, infantile form of osteopetrosis (ARO) was identified as being homozygous for a ClCN7 mutation. From genotype-phenotype correlations, it seems that ADO II reflects a dominant negative effect, whereas loss-of-function mutations in ClCN7 do not cause abnormalities in heterozygous individuals. Because some ARO patients have mutations in both copies of the ClCN7 gene, ADO II is allelic with a subset of ARO cases.

Agonist-stimulated ligand binding by the platelet integrin alpha IIb beta 3 in a lymphocyte expression system

The ligand binding activity of the platelet integrin alpha IIb beta 3 is initiated by agonist-generated intraplatelet signals. We studied this process in vitro by expressing recombinant alpha IIb beta 3 in Epstein-Barr virus-immortalized B lymphocytes. We found that phorbol ester stimulation induced the adhesion of lymphocytes expressing alpha IIb beta 3 to immobilized fibrinogen. Moreover, replacement of the transmembrane and cytoplasmic domains of the alpha and beta subunits of alpha IIb beta 3 with those of alpha L beta 2 significantly increased adherence, whereas replacement of only the cytoplasmic domains significantly decreased adherence. This suggests that transmembrane segments are involved in the agonist-induced modulation of alpha IIb beta 3 activity. Similar results were seen when the alpha IIb beta 3 activation-dependent monoclonal antibody PAC-1 was substituted for immobilized fibrinogen. We also found that the adherence of lymphocytes expressing beta 3 with either of the two alpha IIb/alpha L chimeras was similar to that of cells expressing alpha IIb beta 3, whereas the adherence of cells expressing alpha IIb with either of the two beta 3/beta 2 chimeras was substantially decreased, suggesting that the identity of the cytoplasmic domain of beta 3, but not of alpha IIb, is critical for alpha IIb beta 3 function. This report indicates that B lymphocytes contain signal transduction pathways involving protein kinase C that can increase the ligand binding activity of alpha IIb beta 3 and demonstrates the utility of these cells as an expression system for the study of agonist-stimulated alpha IIb beta 3 function.

Proliferating cell nuclear antigen in developing and adult rat cardiac muscle cells

During early development, rat cardiac muscle cells actively proliferate. Shortly after birth, division of cardiac muscle cells ceases, whereas DNA synthesis continues for approximately 2 weeks at a progressively diminishing rate. Little DNA synthesis or cell division occurs in adult cardiocytes. Thus, developing cardiac muscle cells are an ideal system in which to examine the expression of cell cycle-regulated genes during development. We chose to examine proliferating cell nuclear antigen (PCNA), a gene expressed at the G1/S phase boundary of the cell cycle. Northern blots of RNA from cardiac muscle cells from 18-day-old rat fetuses and from day 0, 5, and 14 neonatal as well as adult rat hearts revealed that the PCNA mRNA was found in cardiac muscle cells from all ages. However, because it was possible that this was a result of fibroblast PCNA gene expression, we used reverse transcription followed by polymerase chain reaction to see if it was possible to detect the message for PCNA in cardiac muscle cells from all ages. Because of the great sensitivity of this technique, RNA was recovered from 25 isolated adult cardiac muscle cells. Polymerase chain reaction amplification products for PCNA produced from the RNA isolated from these cells conclusively demonstrated that mRNA for this gene, which normally is associated with proliferating cells, is expressed in adult cardiac muscle cells that no longer divide. Furthermore, Western blot analysis demonstrated that the PCNA protein was found only in embryonic and neonatal cells and not in adult rat cardiac muscle cells. Therefore, it might be inferred from these data that PCNA might be regulated at the posttranscriptional level in adult cardiac muscle cells.