NASCIS 3 compared the efficacy of a 24-hour MP dose with a 48-hour dose of MP or the non-glucocorticoid tirilazad, which was included to ascertain if it had MP’s effectiveness without possessing MP’s steroid-related side effects (Bracken et al, JAMA 277(2), 1997). Based on the results of the previous NASCIS 2 study, all 499 acutely injured subjects were initially given 30-mg/kg dose of MP within eight hours of injury. Then, patients were randomized to receive 1) a 5.4-mg/kg infusion of MP for 24 hours, 2) the same dose for 48 hours, or 3) 2.5 mg/kg of tirilazad every six hours for 48 hours.

Follow-up assessments were again carried out at six weeks and six months.  The investigators concluded that if MP is initially administered within three hours of injury, the regimen should be continued for 24 hours; if initiated three to eight hours after injury, the regimen should be continued for 48 hours. Patients treated with tirilazad for 48 hours had comparable improvement to the patients treated with the 24-hour MP regimen. MP-associated side effects were greater in patients treated for 48 hours.

Controversy: A growing number of critics believe that MP has been promoted as a standard of care for acute injury based on results obtained through the use of questionable statistical procedures. Simply stated, the NASCIS 2 study showed little if any statistically significant benefits from high-dose MP, and modest benefits were only demonstrated in a patient subgroup when study data was micro-analyzed in a challenged post-hoc fashion.

This controversy is not insignificant. For example, a survey of participants at a 2001 Annual Canadian Spine Society meeting indicated: “75% of respondents were using MP either because everyone else does or out of fear for failing do so.”

The Canadian Spine Society and the Canadian Neurosurgical Society commissioned an expert review of the available MP data, which concluded that there was insufficient evidence to support the use of MP as a treatment standard or guideline, although there is weak clinical evidence to support its use as a treatment option. The two societies adopted these recommendations (see website for Canadian Association of Emergency Physicians: www.caep.ca/002.policies/002-01.guidelines/steriods-acute-spinal.htm).

Some of the published articles that challenge the use of MP as a treatment standard include, but are not limited to, the following:

1) Dr. Shanker Nesathurai (Massachusetts, USA) stated that neither NASCIS 2 or 3 convincingly demonstrated MP’s benefits. “There are concerns about the statistical analysis, randomization, and clinical benefits… Furthermore, the benefits of this intervention may not warrant the possible risks.” (J Trauma 45, 1998)

2) Dr. Deborah Short and colleagues (United Kingdom) extensively reviewed the scientific literature to evaluate the evidence in support of MP’s use (Spinal Cord, 38, 2000). They concluded: “The evidence produced by this systematic review does not support the use of high-dose methylpredinisolone in acute spinal cord injury to improve neurological recovery. A deleterious effect on early mortality and morbidity cannot be excluded by this evidence.”

3) Dr. W.P. Coleman et al (Maryland, USA) strongly criticized both NASCIS 2 and 3 for methodological weaknesses and the lack of data that could be critically reviewed by others (J Spinal Disord 13(3), 2000). For example, they stated: “The numbers, tables, and figures in the published reports are scant and are inconsistently defined, making it impossible even for professional statisticians to duplicate the analyses, to guess the effect of changes in assumptions, or to supply the missing parts of the picture. Nonetheless, even 9 years after NASCIS II, the primary data have not been made public…These shortcomings have denied physicians the chance to use confidently a drug that many were enthusiastic about and has left them in an intolerably ambiguous position in their therapeutic choices, in their legal exposure, and in their ability to perform further research to help their patients.”

4) Dr. R.J. Hurlbert (Alberta, Canada) concluded: “The use of methylprednisolone administration in the treatment of acute SCI is not proven as a standard of care, nor can it be considered a recommended treatment. Evidence of the drug's efficacy and impact is weak and may only represent random events. In the strictest sense, 24-hour administration of methylprednisolone must still be considered experimental for use in clinical SCI. Forty-eight-hour therapy is not recommended.” (J Neurosurg 93(1 suppl), 2000)

5) In perhaps one of the most potentially damning criticisms, Dr. Tie Qian and colleagues (New Jersey, USA) suggested that high-dose MP therapy may damage muscles through acute corticosteroid myopathy (ACM) and that functional improvement attributed to MP may merely be due to the recovery of muscle damage caused by this extremely high dose of MP (Med Hypothesis 55, 2000). The investigators noted that under the NASCI 3 clinical protocol, a 75-kg acutely injured individual could receive nearly 22 gm of MP, which is the “highest dose of steroids during a 2-day period for any clinical condition.”

6) In a recent report, Qian and colleagues (Florida, USA) assessed the possibility that high-dose MP could cause ACM-related muscle damage (Spinal Cord, 43, 2005). Specifically, five acutely injured patients who received the high-dose MP treatment regimen were compared with three control patients, who did not meet the requirements for MP treatment (i.e., 2 gunshot injuries and 1 arrived at hospital 8 hours after injury). ACM was assessed by muscle biopsy and electromyography (EMG). Muscle biopsies indicated that four of the five MP-treated patients had muscle damage consistent with ACM. EMG studies supported these findings. In the controls, muscle biopsies were normal, and EMG’s did not suggest myopathy. The investigators concluded that “the improvement of neurological recovery showed in NASCIS may be only a recording of the natural recovery of ACM, instead of any protection that MP offers to the injured spinal cord.”

2) Sygen® or GM-1 Ganglioside: Like MP discussed above, the degree of effectiveness of Sygen® or GM-1 ganglioside (click on thumbnail) for promoting neurological recovery after acute SCI depends on statistical interpretation. Sygen is the trade name (Fidia Pharmaceutical Corporation) for a naturally occurring GM-1 ganglioside, a complex glycolipid (see figure) found in abundance in central-nervous-system cell membranes.

Animal studies suggest that GM-1 exerts a neuroprotective effect and promotes regeneration after injury. In the acute injury phase, it prevents further cell death and injury by lessening the consequences associated with the injury-induced over-release of excitatory neurotransmitters, which, in turn, over-stimulates their receptors.   In the chronic injury phase, GM-1 promotes the expression of nerve growth factors. In addition to SCI, clinical trials suggest that GM-1 provides benefits in cases of stroke and Parkinson’s disease.

Again, like MP, GM-1’s use to treat acute SCI was the focus of two important clinical trials. In the first, Dr. Fred Geisler et al. (Maryland, USA) randomized patients to receive an intravenous 100-mg dose of GM-1 or placebo within 72 hours of injury (average 48 hours) and continuing for 18 to 32 days (N Eng J Med, 324, 1991). Of the 34 subjects, 23 had cervical injuries and 11 thoracic injuries; and 32 were men. Because all patients were recruited at one center, the procedural variability was inherently less than it would be in multi-center trials.

All patients were given 250-mg dose of MP upon admission and thereafter 125 mg every six hours for 72 hours. This MP dose was much less than that used in the NASCIS-2 study, whose results were not known during this GM-1 study.

Follow-up assessments were carried out twice a week for the first 4 weeks and at 2, 3, 6, and 12 months using the Frankel scale (grade A [complete], B, C, D & E [normal motor functioning]) and the ASIA motor score (0 = complete quadriplegia; 100 = normal motor function).

At one-year, there was statistically significant functional improvement in the GM-1 treated patients compared to controls. For example, in the placebo group, 13 patients stayed in the same grade, 4 improved one grade, and 1 improved two grades. In contrast, in the GM-1-treated group, 8 stayed in the same grade, 1 improved one grade, 6 improved two grades, and 1 improved three grades. In addition, GM-1 treated patients had a statistically significant improvement in the ASIA motor score.

In the second, six-year GM-1 trial, Giesler and colleagues randomized 760 patients recruited from 48 North-American SCI centers into low-dose GM-1 (331 patients), high-dose GM-1 (99 patients) and placebo (330 patients) treatment groups (Spine, 26(24S), 2001). The groups were further subdivided into six subgroups,using 1) injury severity (grade A, B, and combined C+D) and 2) cervical or thoracic injury.  

All patients initially received the NSCIS-2 MP-dosing regimen (i.e., the high dose; not the low dose used in the earlier GM-1 study). GM-1 treatment was not initiated until MP treatment was completed, on average 55 hours after injury. The low-dose GM-1 regimen consisted of an initial 300-mg loading dose followed by 56 days (i.e., 8 weeks) of a 100-mg/day; the high-dose doubled these amounts. Enrollment into the high-dose treatment group was terminated early on.

Follow-up assessments were performed at 1, 2, 4, 6, and 12 months. The study’s pre-defined primary measurement of GM-1 efficacy was the proportion of patients at 6 months with “marked recovery,” defined using various SCI-assessment scales. A secondary efficacy measure included the time course of marked recovery and other established measures of spinal cord function.

Study results were mixed and depended on the time of assessment. For example, although the GM-1-treated group did not have a statistically significant greater number of patients with “marked recovery” at 6 months (i.e., study’s primary efficacy measure), it had statistically significant greater recovery at the end of the two-month dosing period, suggesting that GM-1 accelerates recovery that is obtained. The drug appeared to enhance ASIA motor, light touch, and pinprick scores, as well as bowel function, sacral sensation, and voluntary anal contraction. Finally, GM-1 appeared to exert greater effects on individuals with incomplete injuries.

Although statistical significance was not shown for the pre-defined, primary endpoint, the investigators, nevertheless, believed that GM-1 is “active in SCI, somehow: in some respect, using some regimen, and in some group of patients.” The possibility was suggested that MP and GFM-1 may have antagonistic actions, and, as such, the much higher, NSCIS-2-mandated MP dose administered in the second GM-1 trial may have diminished GM-1’s beneficial effects.  

3) Thyrotropin-Releasing Hormone (TRH) is a three amino-acid peptide (glutamic acid-histidine-proline) produced in the brain’s hypothalamus. In spite of its molecular simplicity, TRH influences diverse biological function through affecting the secretion of a variety of hormones, including thyroid hormone, prolactin, growth hormone, vasopressin, and insulin; and the neurotransmitters noradrenaline and adrenaline.

Experimental studies in a animal models indicate that TRH improves long-term motor recovery after acute, apparently by minimizing some of the biochemical and physiological processes that mediate secondary injury.

In 1995, Dr. Lawrence Pitt and colleagues (California, USA) reported the results of treating 20 acutely injured patients with TRH recruited over a two-year period from 1986–1988 (J Neurotrauma 12(3), 1995). The patients were subdivided into four groups: 1) complete and incomplete injuries and 2) in a double-blind fashion, TRH- or placebo-treated groups. The treatment groups were dosed with 0.2 mg/kg intravenous bolus of TRH followed by an hourly infusion of the same dose for six hours.

Patients were examined at various follow-up periods up using 1) motor and sensory scales in which 0 corresponded to no movement and 5 normal power, and 1 corresponded to no sensation and 3 normal sensation; and 2) a 1-10 Sunnybrook scale in which 1 represented complete motor and sensory loss, and 10 represented normal motor and sensory function.

At the four-months before patient attrition started compromising the study, the TRH-treated group with incomplete injuries demonstrated improved functional recovering using the aforementioned scales. However, no improvement was noted in the TRH-treated group with complete injuries. The investigators emphasize that results must be interpreted with caution due to the small sample size.

Unfortunately, in spite of the pilot-study’s positive results and many promising animal studies, no further work in humans with SCI appears to have been carried out. TRH efforts are now focusing on traumatic brain injury.

4) Gacyclidine: Dr. Alain Privat and colleagues (Montpellier, France) have studied the effectiveness gacyclidine in minimizing neurological damage after acute SCI. Basically, after injury, cells lyse, releasing excitatory amino acids, such as glutamate, which soon reach toxic concentrations. Through interactions with receptors on neighboring cells, excessive glutamate will initiate a neurotoxic biochemical cascade. Animal studies suggest that antagonists that block these receptors will exert a neuroprotective influence by inhibiting this cascade. Gacyclidine is one of these antagonists.

Privat’s study recruited over 200 patients, a relatively large clinical trial for SCI (summarized in Spinal Cord 42, 2004). Most subjects were treated within three hours of injury and once again in the following four hours. Although analysis of the study results indicated no statistically significant difference between the gacyclidine and placebo-treated groups, data suggested that subjects who 1)received the highest drug dose functionally improved, and 2) sustained cervical injuries had the most improvement.

5) Neotrofin®: NeoTherapeutics (Irvine, California) sponsored clinical trials examining the effect of Neotrofin (also called AIT-082 or leteprinim) on several neurological disorders, including Alzheimer’s disease, Parkinson’s disease, and SCI. Neotrofin is a purine analog that can be taken orally, and due to its relatively small size, able to cross the blood-brain barrier, a prerequisite for any drug that targets central nervous system (CNS) disorders.

Animal studies indicate Neotrofin reduces neurological damage and improves walking after acute injury in rats (Middlemiss, et al. Soc Neurosci Abstr, 25, 1999). Evidence suggests that Neotrofin stimulates the production of neurotrophic factors, such as nerve growth factor and protects neurons from glutamate-induced cell death (see previous section). Studies in mice indicate that the drug also stimulates the proliferation of CNS stem cells, which given the increasing number of SCI-related stem-cell programs may have important implications.

In 2001, NeoTherapeutics started the recruitment of an intended 30-40 patients with complete SCI one to three weeks after injury (i.e., sub-acute injury phase) at four SCI centers: Thomas Jefferson University (Pennsylvania), Craig Rehabilitation Center (Colorado), Rancho Los Amigo (California), and Gaylord Hospital (Connecticut). Patients orally consumed a twice daily 250-mg dose of Neotrofin for 12 weeks.

Unfortunately, few, if any, study results have been reported. After Neotrofin failed to demonstrate a statistically significant effect in late-stage clinical trials for Alzheimer’s disease, the nearly broke NeoTherapeutics reorganized into Spectrum Pharmaceuticals with an emphasis on cancer drugs.   

6) Minocycline: A broad-spectrum antibiotic in the tetracycline group, minocycline is often used to treat acne and rosacea. Compared to other tetracyclines, minocycline is eliminated more slowly from the body, and, hence, exerts a longer physiological effect.

Studies in animal models of acute SCI indicate that minocycline minimizes the secondary neurological damage that occurs soon after injury. For example, University of Calgary researchers have shown that acutely injured, minocycline-treated mice recover more hind-limb function and strength compared to untreated mice. In addition, minocycline reduced the size of the injury-site lesion and promoted the survival of axons through the injury site (Wells JE, et al, Brain, 126(7), 2003). Harvard University (Teng YD et al, Proc Natl Acad Sci, 101(9), 2004) and South Korean investigators (Lee SM et al, J Neurotrauma, 20(10), 2003) have also demonstrated similar neuroprotective effects in rats.

Minocycline mediates its neuroprotective effects through a number of mechanisms, including minimizing the destructive, post-injury immune response and the release of cytochrome c. Although cytochrome c is a key cell-respiratory protein essential for cell life, when it is released, it initiates a metabolic cascade triggering cell death.

Based on the results of these animal studies, the Canadian investigators, led by Dr. John Hurlbert, have initiated a randomized, double-blind, placebo-controlled, phase-1 study evaluating the effects of minocycline administered within 12 hours of injury in 20 subjects (see Jha et al, Spinal Cord Inj Rehabil, 11(3), 2006). The minocycline will be intravenously administered in twice-daily, 250-mg doses for seven days and compared to saline infusion. The patients will be followed for a year using a variety of assessments, including the ASIA- impairment scale. Study results will be used to guide the design of a larger multi-center study.

7) Cethrin^® Based on the research of its founding scientist Dr. Lisa McKerracher (Canada), Bioaxone Therapeutics/Boston Life Sciences/Alseres Pharmaceuticals has initiated clinical trials evaluating Cethrin in 37 patients with acute SCI (22).  Animal studies indicate that SCI stimulates the production of  Rho, a molecule that inhibits axonal growth and regeneration, and initiates a physiological cascade that results in the death of nearby neuronal cells (a process called apoptosis). Cethrin apparently blocks these adverse effects, restoring regenerative potential and preventing cell death.

This preliminary clinical trial was designed to test Cethrin’s safety and pharmacokinetics at various dosing regimens, and did not include control subjects necessary to determine overall effectiveness. The drug was administered an average of 53 hours after injury at the time of spinal-stabilization/decompression surgery, a procedure often done soon after injury. As the surgery is being completed, Cethrin was applied on the membrane covering the spinal cord using a sealant to keep it in place. The drug penetrates through the membrane to the underlying neuronal tissue.

8) Tacrolimus & Minocycline: Although available details are scant, investigators at Riyadh Armed Forces Hospital, Saudi Arabia have initiated a clinical trial assessing the effectiveness of tacrolimus and minocycline in reducing neurological damage after acute SCI. Minocycline is discussed above. Tacrolimus (also called FK506) is an antibiotic originally obtained from soil bacteria. It is primarily used to 1) suppress the immune system to minimize rejection of transplanted organs and 2) topically to treat eczema. Animal studies suggest that it exerts a neuroprotective effect that may be greater than the currently widely used methylprednisolone (Exp Neurol 1998; 154(2); Exp Neurol 1999; 158(2); Exp Neurol 2002; 177(1); & J Neurosci Res 2005; 81(6)). Tacrolimus inhibits calcineurin, an enzyme found in neurons and lymphocytes (white blood cells).  This inhibition apparently prevents lymphocyte activation, in turn attenuating the destructive, post-injury immune process.

9) Lipitor (Atorvastatin): A cholesterol-lowering medicine belonging to the statin-drug group, Lipitor (trade name for atorvastatin) is one of society’s most widely used and profitable drugs. By inhibiting the liver’s enzymatic production of a cholesterol precursor, it lowers cholesterol levels.  Animal and clinical studies suggest that Lipitor or related statins exert a neuroprotective and anti-inflammatory influence for various neurological disorders, including MS, Alzheimer’s disease, stroke, and SCI.

Drs. Avtar and Inderjit Singh and colleagues (South Carolina, USA) have carried out several studies indicating that Lipitor minimizes neurological damage in rats with an experimental contusion injury (i.e., comparable to the sort of injury observed in most humans).  In the first study, rats treated before and after injury with Lipitor recovered more hind-limb function than control animals (J Neurosci Res. 79(3), 2005). 

A more recent study showed that this neuroprotective effect was also observed when the rats were given Lipitor only after injury, a finding, of course, needed if the drug is to have any real-world applicability (J Neurochem; 101, 2007). Specifically, rats were given oral doses of Lipitor two, four, or six hours after injury followed thereafter by a once daily dose. Compared to controls, Lipitor-treated rats regained considerable recovery in hind-limb function, with the earlier treated rats regaining the most.

Apparently, Lipitor helped preserve the blood-spinal-cord barrier after injury, which, in turn, limited the infusion into the injury site of inflammatory molecules that cause function-compromising secondary damage. Overall, there was more tissue sparing in Lipitor-treated rats, including 1) less degeneration of neuronal axons, 2) degradation of the conduction-promoting, axon-insulating myelin sheath,  3) scar-forming gliosis (the production of a dense complex of neuronal support cells called glia in the injury area), and 4) apoptotic cell death. 

Lipitor also suppresses the injury-induced expression of Rho (see discussion above), a molecule that inhibits axonal growth and regeneration, and initiates a physiological cascade that results in the death of nearby neuronal cells.

10) Erythropoietin (EPO): EPO (Epogen^®) is a glycoprotein growth hormone produced by the kidney that stimulates the bone-marrow production of red blood cells. In a feedback fashion, decreases in blood-oxygen levels trigger EPO synthesis, which, in turn, results in the creation of more oxygen-carrying red blood cells. EPO has been primarily used in the treatment of kidney disease, in which EPO production has been compromised, and cancer to ameliorate the side effects of chemotherapy- or radiation-induced anemia. Because of EPO’s ability to promote oxygenation, endurance athletes have used the drug as a blood-doping agent to obtain a competitive advantage.

More recently, it has been shown that EPO is also created by the CNS and exerts a neuroprotective influence for a variety of neurological disorders, including stroke, head injury, and SCI. In the case of SCI in animal models, a number of interacting physiological mechanisms may mediate EPO-influenced neuroprotection: Specifically, EPO

Given EPO’s well-documented neuroprotective effect in injured animals, Italian investigators have initiated a multicenter clinical trial comparing the effectiveness of EPO with methylprednisolone (MP, discussed previously) for treating acute SCI. The study intends to recruit 100 subjects at Italian SCI centers within eight hours of injury and randomize them to receive either MP or EPO. All subjects must have more complete ASIA A-B injuries (i.e., the most neurologically complete injuries; see appendix). Relative improvement will be periodically measured over three months using this ASIA-impairment scale, as well as assessments evaluating neuronal conduction (i.e., electrophysiology), spasticity, pain, and functional autonomy.

11) Anti-Nogo: Since the 1980’s, Dr. Martin Schwab and colleagues (Switzerland) have been investigating factors that inhibit neuronal regeneration after injury and, in turn, the blocking of these factors as a means to promote functional recovery. His research was based on the findings by others, which showed that usually regeneration-reluctant, spinal-cord neurons are able to grow when placed in the peripheral-nervous-system (PNS - nerves outside of the brain and spinal cord). These findings suggested that a CNS environmental factor inhibited neuronal regeneration which did not exist in the PNS. Schwab demonstrated the factor was associated with CNS myelin, the insulating material surrounding neurons. CNS and PNS myelin are dissimilar, generated by different cells called oligodendrocytes and Schwann cells. The CNS oligodendrocyte-derived myelin possesses a protein dubbed Nogo that repels the growth cones of neuronal axons attempting to regenerate. To negate this inhibition, Schwab’s team developed an antibody that complexes with Nogo, hence, neutralizing or blocking Nogo.

As a crude analogy, visualize the Nogo-growth inhibitors as burrs sticking to your clothing unless they are so filled with lint that they fall away. Essentially, the anti-Nogo antibodies represent the molecular lint that preferentially sticks to the Nogo burrs, keeping them from attaching to struggling growth cones. These regenerating cones can now move forward in the spinal cord with less inhibitory drag.

In several SCI animal models, including rats and primates, Schwab and colleagues have shown that anti-Nogo antibodies promote functional recovery. This recovery is apparently due to not only the regeneration of injury-affected neurons but the stimulation of sprouting in neurons bypassing the injury site. Based on these experiments, the Swiss company Novartis in collaboration with Schwab has initiated preliminary clinical trials in humans injured within 10 days of treatment. 

12) Ibuprofen: Even though ibuprofen’s SCI-treatment potential has only been explored in animal models (like Lipitor discussed above), this drug is included in this discussion because its widespread consumption makes it much easier candidate to be considered for SCI applications.  Marketed under many brand names (e.g., Advil, Motrin, etc), ibuprofen is categorized as a non-steroidal anti-inflammatory drug (NSAID – like aspirin). The drug works by inhibiting the production of prostaglandins, which mediate inflammation.

As is the case with both Cethrin and Lipitor summarized before, ibuprofen blocks the injury-triggered production of Rho.  Again, Rho is a protein that inhibits axonal growth and regeneration, and initiates a physiological cascade that ultimately results in the death of nearby neuronal cells (a process called apoptosis).

Dr. Shuxin Li and colleagues (USA) have shown that by blocking Rho, ibuprofen stimulates the growth of not only neurons grown in culture but within the injured spinal cord (31).  Specifically, subcutaneous injection (via mini-pump) of ibuprofen into rats with experimental SCI stimulated considerable axonal sprouting. Compared to untreated control animals, ibuprofen-treated rats regained additional walking ability. The investigators concluded that “ibuprofen promotes a remarkable locomotor functional recovery, even when delivered 1 week after trauma. The axon growth-promoting effect and the common use of ibuprofen in patients raise the high possibility that” it may be an effective SCI treatment.

TOP