Theophylline Treatment for Pseudohypoparathyroidism - Children 2-12 Years Old

Sponsor

Vanderbilt University Medical Center (Other)

Overall Status

Recruiting

CT.gov ID

NCT04551170

Collaborator

(none)

Enrollment

Location

Arms

59.6

Anticipated Duration (Months)

0.6

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Pseudohypoparathyroidism is a genetic disorder with limited treatment options, characterized by early-onset obesity, short stature and resistance to multiple hormones. This phase 2 clinical trial and open-label extension study will test the efficacy of theophylline, a phosphodiesterase inhibitor, in pseudohypoparathyroidism. We hypothesize that theophylline will cause weight loss, slow the rate of growth plate closure and decrease hormone resistance in children.

Condition or Disease	Intervention/Treatment	Phase
Pseudohypoparathyroidism Albright Hereditary Osteodystrophy Pseudohypoparathyroidism Type 1a	Drug: Theophylline Drug: Placebo	Phase 2

Detailed Description

Pseudohypoparathyroidism (PHP) is a rare, genetic disorder caused by impaired stimulatory G protein (Gsα) signaling through downregulation of the gene, GNAS. The resultant hormone abnormalities can be treated with hormone replacement therapy, but other aspects of the disorder such as early-onset obesity and short stature are without effective treatment options. Gsα signaling is essential for the normal hormonal function of the pituitary, thyroid, gonads, renal proximal tubules and hypothalamus. While many of the resulting hormone deficiencies can be treated with hormone replacement therapy (HRT), HRT is not an effective therapy for the severe early-onset obesity and short stature which are major features of the PHP phenotype. Therefore, the goal of this clinical trial is to test the efficacy of upstream therapy aimed at correcting the function of Gsα-dependent receptors in children with PHP. Gsα-coupled receptor signaling cascade begins with an increase in cyclic adenosine monophosphate (cAMP) which is rapidly degraded by the enzyme phosphodiesterase (PDE). PDE inhibitors act by prolonging cAMP signaling by decreasing the rate of degradation. Given that patients with PHP have reduced, but not completely absent, cAMP production, the investigators seek to test the hypothesis that the PDE inhibitor theophylline will reduce body mass index (BMI), slow the rate of epiphyseal closure, and decrease hormone resistance in children with PHP through improved Gsα-coupled receptor signaling. The investigators will conduct a 52-week randomized, placebo-controlled clinical trial of theophylline in children with PHP. Theophylline is a non-selective PDE inhibitor that is generically available and has a long history of use in pediatric patients, making it an ideal drug for repurposing in youth with PHP. Furthermore, the pharmacokinetics of theophylline are well understood, and serum drug levels are easily measured. Our primary outcome is change in BMI. Secondary outcome measures include change in epiphyseal closure and HRT medication doses.

Study Design

Study Type:

Interventional

Anticipated Enrollment :

34 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)

Primary Purpose:

Treatment

Official Title:

Phase 2 Study of Theophylline Treatment for Pseudohypoparathyroidism

Actual Study Start Date :

Jul 13, 2020

Anticipated Primary Completion Date :

Jun 30, 2025

Anticipated Study Completion Date :

Jun 30, 2025

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Theophylline Theophylline capsules by mouth once daily or Theophylline elixir by mouth q6h (dose determined by serum drug levels)	Drug: Theophylline oral theophylline Other Names: Theo-24 Elixophyllin
Placebo Comparator: Placebo Placebo capsule by mouth once daily or Placebo elixir by mouth q6h	Drug: Placebo Placebo capsule or elixir

Arm

Intervention/Treatment

Experimental: Theophylline

Theophylline capsules by mouth once daily or Theophylline elixir by mouth q6h (dose determined by serum drug levels)

Drug: Theophylline

oral theophylline

Other Names:

Theo-24

Elixophyllin

Placebo Comparator: Placebo

Placebo capsule by mouth once daily or Placebo elixir by mouth q6h

Drug: Placebo

Placebo capsule or elixir

Outcome Measures

Primary Outcome Measures

Change in body mass index [baseline and 52 weeks]
BMI expressed as percent of the 95th percentile

Secondary Outcome Measures

Change in levothyroxine dose [baseline and 52 weeks]
levothyroxine dose (mcg/kg/day)
Change in calcitriol dose [baseline and 52 weeks]
calcitriol dose (mcg/kg/day)
Change in epiphyseal closure [baseline and 52 weeks]
Bone age minus chronologic age

Eligibility Criteria

Criteria

Ages Eligible for Study:

2 Years to 12 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Age 2 to 12 years old
Clinical diagnosis of PHP (per the EuroPHP network classification guidelines5): Presence of PTH resistance and/or ectopic ossification OR brachydactyly type E plus 2 minor criteria (TSH resistance, other hormonal resistance, developmental delay, intrauterine or post-natal growth retardation, obesity/overweight, specific facial features)
Obesity (BMI >95th percentile for age/gender and/or ≥30 kg/m2)

Exclusion Criteria:

Use of a PDE inhibitor in the past 30 days
History of a seizure disorder unrelated to hypocalcemia
History of a cardiac arrhythmia (not including bradycardia)
Hepatic insufficiency including cirrhosis and acute hepatitis (AST or ALT >3x upper limit of normal)
Congestive heart failure
Current cigarette use or alcohol abuse
Pregnancy or intention to become pregnant during the next year
Untreated hypothyroidism (defined as free thyroxine below the lower limit of normal)
Active peptic ulcer disease
Current use of medications known to effect theophylline levels (see protection of human subjects)
History of hypersensitivity to theophylline or other medication components
History of Major Depressive Disorder in the past 2 years, lifetime history of suicide attempt, history of any suicidal behavior in the past month, history of other sever psychiatric disorders (e.g. schizophrenia, bipolar disorder)
PHQ-9 score is ≥15 or suicidal ideation of type 4 or 5 (C-SSR) in the past month
Untreated hypothyroidism or uncontrolled PTH resistance (PTH >2x upper limit of normal), or treatment of these disorders by medications other than calcitriol or levothyroxine (such as Cytomel or Armour thyroid)
Unable to comply with study procedures in the opinion of the investigator