Phase II/III placebo-controlled randomized trial of safety and efficacy of growth hormone treatment in incomplete chronic traumatic spinal cord injury

This is a double blind phase II/III placebo-controlled randomized trial of the safety and efficacy of GH treatment in incomplete chronic traumatic spinal cord injury.

The aim of this study was to investigate the possibility to use exogenous GH administration for motor recovery in chronic traumatic incomplete human SCI. The objectives were to establish

safety and efficacy of a combined treatment of subcutaneous GH (or placebo) and rehabilitation in this population.

The pharmacological treatment was a subcutaneous daily dose of growth hormone (GH, Genotonorm 0.4 mg, Pfizer Pharmaceuticals) or placebo for one year. The pharmacological treatment was

performed, during the first six months under hospitalization and supervised rehabilitation.

The main findings were that the combined treatment of GH plus rehabilitation treatment is feasible and safe, and that GH but not placebo increases the ISNCSCI motor score. On the other hand,

the motor-score increment was marginal (after one-year combined treatment, the mean increment of the motor-score was around 2.5 points). Moreover, we found that intensive and long-lasting

rehabilitation program per se increases the functional outcome of SCI individuals (measured using SCIM III and WISCI II).

It is important to highlight that our aim was to propose GH as a possible treatment to improve motor functions in incomplete SCI individuals. At least with the doses we used, we think that

the therapeutic effects of this approach are not clinically relevant in most subjects with SCI.

Recovery or improving motor abilities is one of the main goals of patients after traumatic spinal cord injury (SCI), being associated with quality of life and satisfaction [1]. More than 50%

of people with SCI have motor-incomplete lesions. The proportion of incomplete SCI has been increasing [1, 2], and most of the motor recovery occurs within months after injury. After 12–18

months, usually no further spontaneous motor recovery is possible [2]. Many different strategies have been proposed to recover motor functions beyond the spontaneous recovery. Nowadays, not

even one is considered effective.

Growth hormone (GH), also known as somatotropin, is a peptide hormone that is synthesized and secreted by the somatotrophs of the anterior pituitary gland [3].

Its secretion is mainly regulated by the hypothalamic GH‐releasing hormone (GHRH) as a stimulator and by somatostatin as inhibitor [4]. Once released in the bloodstream, GH reaches the

target organs. Classically, the effect of GH includes hyperglycemia, lipolysis and protein anabolism, and it has direct effects on cellular proliferation and differentiation. The anabolic

effects of GH are mediated by insulin-like growth factor-I (IGF1), which stimulates whole-body protein synthesis, including skeletal muscle and collagen proteins. The stimulation of muscle

protein anabolism and growth by GH has led to the hypothesis that GH use would increase muscle strength and power. Indeed, starting from the early 1980s, GH became increasingly used as a

doping agent by athletes, subsequently entering the list of banned substances [5].

IGF1 is produced primarily in the liver, and in various tissues throughout the body. In response to GH [6], IGF1 regulates growth, glucose uptake, and protein metabolism (i.e.,

IGF1‐dependent GH effects). IGF1‐independent GH effects include stimulation of insulin secretion, lipolysis, and gluconeogenesis [7]. GH can cross both the blood [8] and CSF–brain barriers

[9, 10], as does the IGF1 [11]. The GH/IGF1 axis has been implicated in physiological brain functioning, neurogenesis, myelination, and synaptic plasticity [12, 13]. Moreover, GH and IGF1

play a role in muscle metabolism [14]. For the combined effects over muscle and central nervous system, GH and IGF1 can be considered as potential drugs to improve motor functions in SCI,

even in a chronic stage. Some case report supported this hypothesis [15,16,17].

Several promising therapies to improve motor functions in SCI have been translated into clinical trials, but none have yet proven to be of significant benefit in humans nor in the acute or

in the chronic stage [18]. Failure of translation may be attributed to several factors, among the most relevant ones is the greater heterogeneity of human SCI when compared with experimental

animal models with subsequent variability in spontaneous neurological recovery [2]. Furthermore, it must be acknowledged that animal models do not fully represent the human condition and

secondary-injury mechanisms may vary in importance and timing among species.

Since exogenous GH administration is generally considered safe, we decided to test the effects of GH administration concomitantly with rehabilitation [19,20,21]. The aim of this study was to

investigate the possibility to use GH exogenous administration for motor recovery in chronic traumatic incomplete human SCI. Our objectives were to establish the safety and efficacy of a

combined treatment with subcutaneous GH (or placebo) and rehabilitation in this population. To guarantee a homogeneous rehabilitation and compliance with the treatment, we decided that

during the first six months, all participants were hospitalized.

A total of 54 SCI participants were enrolled for the clinical trial (mean age 36.3 ± 9.9, range 21–71 years). The clinical trial was approved by the local ethical committee and by the

Spanish Drug Agency (AEMPS) and registered on ClinicalTrials.gov (NCT01329757). To favor the recruitment, the clinical trial was announced on the webpage of the Hospital Nacional de

Parapléjicos (HNP) and on the Spanish media.

The first step was an assessment for eligibility initially made by a phone interview. The flowchart is reported in Fig. 1. After this step, participants were screened immediately before or

after the hospitalization. We used the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) [22] to classify subjects using the ASIA Impairment Scale

(AIS); neurological level of SCI (the more caudal neurological level with normal neurological function) and the following clinical data were also collected: age, cause of the lesion, and

time since SCI lesion. Moreover, we performed interviews, revised clinical records, obtained vital signs, ECG, and blood and urine samples to evaluate the general medical condition of the

patients. Blood sample was also used to evaluate basal levels of IGF1. ISNCSCI [22] is the standard evaluation of the SCI patients: it includes muscle function grading, sensory grading,

neurological level, and AIS. AIS is used to classify the patients in five main groups A–E. Only patients with AIS B and C were included in the study. All these examinations and procedures

were performed by a physical medicine and rehabilitation specialist. All subjects with traumatic SCI were assessed and screened for this trial. Those who met the inclusion criteria were

offered enrolment (Table 1). Following written informed consent and prior to randomization patients were hospitalized at the HNP. A sample size of 62 subjects, 31 in each arm, was estimated

to be sufficient to detect a clinical difference of five points between groups in increasing motor score assuming a standard deviation of seven using a two-tailed t-test of the difference

between means with 80% power and a 5% level of significance. Considering a dropout rate of 25%, the sample size required is 76 (38 per group). After the screening, we finally enrolled and

randomized 54 SCI patients (the main clinical and demographic and characteristics are reported in Table 2). The whole period for recruitment and follow-up lasted six years, that was longer

than expected (so we decided to end the trial).

The flowchart shows the number of individuals that were recruited and included in the final analysis.

This is a double-blind phase II/III placebo-controlled randomized trial of the safety and efficacy of HGH treatment in incomplete chronic traumatic spinal cord injury. The pharmacological

treatment was GH (subcutaneous daily dose of Genotonorm 0.4 mg, Pfizer Pharmaceuticals) or placebo for one year. The pharmacological treatment was associated, during the first six months, to

hospitalization and supervised rehabilitation. After six months, the patients were discharged and continued the treatment at home (not supervised). Physical therapy was individualized,

depending on neurological level and AIS of the participants of both the GH and placebo groups. The physical therapy was individualized to take into account the SCI individual difference

(e.g., neurological level). On the other hand, the professional prescribing the physical therapy was blinded to the pharmacological therapy received (GH or placebo). Therapy time was 1 h

every morning and 2 h every afternoon for 5 days per week (Monday to Friday) for 6 months. The afternoon therapy included sport activity. Patients were allowed to practice sport activity

during the weekend. The clinical trial goal was to test the safety and efficacy of the combined treatment.

Subjects were randomized (parallel assignment, 1:1) to receive GH (Genotonorm 0.4 mg, Pfizer Pharmaceuticals) or placebo (equal volume of normal saline using the same syringe system). For

this purpose, sets of 20 envelopes containing a card indicating the placebo or GH kits were prepared. The cards were randomly inserted into the envelopes and then the envelopes were

sequentially numbered and sealed. The cards and the envelopes were prepared by an independent individual not otherwise involved in the patient selection and evaluation. Different 20 envelope

kits were prepared. For this study, we used three kits (allowing a randomization of up to 60 patients). When enrolled, patients were administered the next available envelope code,

corresponding to a placebo or GH kit. All subjects and medical and research personnel (including nurses and therapists) were blinded to treatment until the end of the study. To test if

masking was effective at 6- and 12-month follow-up, subjects and evaluators were given a forced-choice question about whether GH or placebo was received to verify the correct masking.

Safety and clinical variables were collected at Days zero and 15, and Months six and 12. Trial monitoring to ensure data quality was internally performed. After the drug administration

started, participants were evaluated for adverse events daily while in hospital and at each clinical evaluation (and on demand) subsequently. All serious adverse events were reviewed

promptly by clinicians and clinician researchers not otherwise involved in this study. A summary of all serious adverse events was reviewed every 6 months.

Vital signs, ECG, and blood and urine samples were collected at each visit for safety. Moreover, we collected info about pain and spasticity. Pain was graded with a numeric rating scale

(NRS), the NRS is a pain rating from zero, no pain, and 10, maximum pain. Spasticity was graded using Modified Ashworth Scale (MAS) and spasms were measured using Penn Spasm Frequency Scale

(PSFS) [23, 24]. Neurological level and AIS score were also considered safety variables to detect possible neurological worsening.

The main effects of the GH exogenous administration are mediated by the subsequent IGF1 increment. For this reason, we monitored the baseline value and the time course of IGF1.

Neurological function was assessed at intervals using the American Spinal Cord Injury Association (ASIA) and International Spinal Cord Society (ISCoS) standardized neurological examination,

including the motor and sensory composites. We used the ISNCSCI [22] to evaluate the SCI subjects and the following clinical data were collected: cause of the lesion, AIS, neurological level

of SCI, motor score (muscle function grade sum for key muscle strength in upper and lower extremities), sensory scores (sensory grade sum of pin prick and of light-touch sensations in each

key sensory point), and time since SCI lesion. The Motor Score uses standard manual muscle testing on a six-grade scale: 0: total paralysis; 1: visible or palpable contraction; 2: active

movement through range of motion with gravity eliminated; 3: active movement through range of motion against gravidity; 4: active movement through range of motion against gravity and

moderate resistance in specific position; 5: active movement through range of motion against full resistance in specific position; 5*: normal if inhibiting factors were not present and NT = 

not testable. The key muscles/functions included in the Motor Score are elbow flexors, wrist extensors, elbow extensors, finger flexors, finger abductors, hip flexors, knee extensors, ankle

dorsi flexors, long-toe extensors, and ankle plantar flexors, whereas a total motor score of 100 is possible. In this clinical trial, the main variable was the motor score of the ISNCSCI.

Secondary-outcome variables were Patient Global Impression of Change (PGIC), AIS conversion, ISNCSCI sensory scores (pin prick and light touch), Spinal Cord Independence Measure (SCIM III),

Walking Index for Spinal Cord Injury (WISCI II), and EQ-5D. The Spinal Cord Independence Measure third version (SCIM III) is a scale for the assessment of achievements of daily function of

patients with spinal cord lesions. It contains 19 tasks organized in three subscales: self-care, respiration and sphincter management, and mobility. A total score out of 100 is achieved,

with the subscales weighted as follows: self-care: scored 0–20; respiration and sphincter management: scored 0–40; and mobility: scored 0–40 [25].

The Walking Index for Spinal Cord Injury (WISCI II) is a functional capacity scale developed to measure improvements in ambulation in persons with spinal cord injury, by evaluating the

amount of physical assistance, braces or devices required to walk 10 meters. A score from 0 to 20 is assigned. Level 0: the patient is unable to stand and/or participate in walking to level

20: ambulates with no devices, with no brace and no assistance [26].

EQ-5D is an instrument that evaluates the generic quality of life, with one question for each of five dimensions that includes mobility, self-care, usual activities, pain/discomfort, and

anxiety/depression [27].

The self-report measure PGIC reflects a patient’s belief about the efficacy of treatment. PGIC is a 7-point scale depicting a patient’s rating of overall improvement. Patients rate their

change as “very much improved,” “much improved,” “minimally improved,” “no change,” “minimally worse,” “much worse,” or “very much worse” [28,29,30,31].

Data are reported as mean ± standard deviation for parametrical variables and median and range for nonparametrical variables. The first step of our statistical analysis was to compare the

demographic and clinical data of the two groups. Male/female and neurological-level (cervical or thoracic) ratios were compared using a χ2 test. A Student t-test was used to estimate the

between group difference of age, time since SCI, and IGF1. AIS (A–E), motor score, sensory scores (pin prick and light touch), SCIM III, WISCI II, pain (NRS), spasticity (MAS and PSFS) and

EQ-5D were compared using Mann–Whitney test. To test if masking was effective at 6- and 12-month follow-up, subjects and evaluators were given a forced-choice question about whether GH or

placebo was received and compared using a χ2 test.

The second step of our statistical analysis was to compare the safety-variable changes over time of both groups. Vital signs, ECG, blood (including thyroid hormones) and urine results were

used to identify clinical and subclinical safety concerns. AIS conversion and neurological level were evaluated at 15 days at 6 and 12 months. after the start of treatment (Mann–Whitney

test). The number of adverse events between groups was compared (Mann–Whitney test). Normalized NRS, MAS, and PSFS changes produced by the treatment were evaluated using a repeated-measures

ANOVA. These variables were evaluated by the Kolmogorov–Smirnov normality test and were consistent with a normal distribution. Data were entered into separate repeated-measures ANOVA, with

TIME (baseline, 15 days, 6 months, and 12 months) as within-subject’s factors and GROUP (GH or placebo) as between-subject’s factors. In case of significant effects, Fisher’s Least

significant difference (LSD) test was used for post hoc comparisons. During ANOVA execution, the degrees of freedom were corrected with Greenhouse coefficients if sphericity could not be

assumed.

The third step of our statistical analysis was to evaluate the time course of IGF1. IGF1 values were evaluated by the Kolmogorov–Smirnov normality test and were consistent with a normal

distribution. Data were entered into a repeated-measures ANOVA, with TIME (baseline, 15 days, 6 months, and 12 months) as within-subject’s factors and GROUP (GH or placebo) as

between-subject’s factors. In case of significant effects, Fisher’s Least significant difference (LSD) test was used for post hoc comparisons. During ANOVA execution, the degrees of freedom

were corrected with Greenhouse coefficients if sphericity could not be assumed. As IGF1 is age-dependent, this analysis was also repeated incorporating age as a covariate (ANCOVA).

The last step of our statistical analysis was to compare the clinical variable changes after one year of treatment. Data were normalized by dividing each value for the baseline mean. As the

principal variable (Motor Score) concerns, we evaluated the changes after one year of treatment (baseline and 12 months) and over time (baseline, 15 days, 6 months, and 12 months).

Normalized ISNCSCI motor scores were evaluated by the Kolmogorov–Smirnov normality test and were consistent with a normal distribution. Motor-score changes produced by the treatment were

evaluated using a repeated-measures ANOVA with TIME as within-subject’s factors and GROUP (GH or placebo) as between-subject’s factors. The following covariates (baseline values) were added

to the model to correct for all the possible confounding factors (ANCOVA): age, sex, time since injury, AIS, motor and sensory levels, motor and sensory scores (pin prick and light touch),

SCIM III, WISCI II, pain (NRS) and spasticity (MAS and PSFS). The degrees of freedom were corrected with Greenhouse coefficients if sphericity could not be assumed. Fisher’s Least

significant difference (LSD) test was used for post hoc comparisons.

Normalized ISNCSCI sensory scores, SCIM III, WISCI II and EQ-5D, were similarly evaluated, with the exception that for SCIM III, WISCI II and EQ-5D, no covariates were added to the model.

PGIC was evaluated only at 6 and 12 months after the start of treatment. We used a Mann–Whitney test to compare GH and placebo groups. AIS conversion was evaluated at 15 days, 6, and 12

months after the start of treatment (Mann–Whitney test).

For significant variables, we also calculated the standardized difference (Cohen’s D), considering a small-effect size d~0.20; medium-effect size d~0.50; large-effect size d~0.80;

very-large-effect size d~1.30.

All statistical analyses were performed with the software STATISTICA. The results were considered significant at p