**9. Preliminary clinical observations**

In a proof of concept trial in 8 patients of both sexes between the ages of 2.75 to 24 years of age and without Rett or Fragile X syndrome. Doses began at doses of 90 mg tid and were escalated to 200 mg tid for most patients with two patients receiving a brief course at 400 mg tid, which was not found to increase efficacy. All doses were well tolerated. Patients were washed out of their legacy medications and 6 patients were maintained on L1-79 alone. Two patients were restarted on one of their legacy medications at lower than their pre-study dose. L1-79 in this study had a therapeutic effect on the core symptoms of autism as defined by the ABC-C (**Figure 1**), the CPRS (**Figure 2**), ADOS (**Figure 3**), and the CGI (**Figure 4**). This includes improvements in socialization, communication, repetitive movements, sleep disturbances, and other symptoms of ASD. Interestingly, the Autism Diagnostic Observation Schedule 2 (ADOS), which is the "gold standard" for quantifying the lifetime severity of ASD was profoundly influenced by L1-79 treatment. In the 6 patients in whom the ADOS was measured a mean decrease of 30% was observed with one patient experiencing a reduction of 47% (**Figure 3**) which took him below the threshold for a diagnosis of autism following 10 weeks of treatment, although

#### **Figure 1.**

*Proof of concept study: Aberrant behavior checklist-community (ABC-C) scores. Domain scores for each participant during weeks 1 to 8. Because of participant-specific factors, ABC-C scores were not recorded at all visits for all participants.*

#### **Figure 2.**

*Proof of concept study: Connor parent rating scale (CPRS) at 4-week intervals for 8 participants. Some participants did not have all assessments.*

#### **Figure 3.**

*Proof of concept study: Autism diagnostic observation schedule (ADOS) scores for the 6 participants tested at baseline and week 10.*

**113**

*L1-79 and the Role of Catecholamines in Autism DOI: http://dx.doi.org/10.5772/intechopen.95052*

were observed rapidly.

**Figure 4.**

(**Figure 9**).

he was still on the spectrum [236]. As can be seen in the ABC-C scores, these effects

*Proof of concept study: Clinical global impressions (CGI) scores for 8 participants. Top panel shows absolute scores at week 1 and week 8. Bottom panel shows the change from week 1 to week 8. The qualitative interpretation at week 1 appears above each participant change in score, and the interpretation at week 8 is* 

*shown below each bar. Each participants efficacy index at week at appears at the bottom.*

A follow-up randomized, double blind, placebo-controlled 28-day study of 39 patients has been completed and the results are currently in preparation for publication [237]. While 28 days was too short to demonstrate much of an effect, per the FDA the existing toxicology did not permit a longer treatment duration at that time. Participants were male patients between the ages of 13 and 21 years of age with a diagnosis of ASD based on DSM-5 criteria and confirmed by Autistic Diagnosis Interview-Revised (ADI-R), ADOS and expert clinical opinion, stable on no more than one concomitant medication with no planned changes in psychosocial interventions during the study and sufficiently tolerant and capable of complying with the requirements for this study. Results from this brief study can be seen for the CGI (**Figure 5**), Social Response Scale-2 (SRS) social motivation T scores (**Figure 6**), ADOS (**Figure 7**), Vinland Adaptive Behavior Scale-II (VABS) socialization standard score (**Figure 8**), and the SRS DSM-SCI T scores

Anecdotally, numerous salutary behaviors were observed in these studies. Two teenage boys hugged and kissed their parents for the first time. One teenager with a history of self mutilating behavior stopped hurting himself. Subjective aspects of socialization such as empathy, effective communication, emotional expression, better sleep patterns, and engagement with peers were reported by parents and

The proof of concept study was conducted under the assumption that, per the 505(b)(2) guidelines, any stereoisomer of a drug is considered to be the same drug, and therefore the use of L1-79 was an unapproved use of an approved agent (Demser). In subsequent discussions with the FDA this was disallowed. The FDA required that the proof of concept study be discontinued and approved a follow-on pilot study that was limited to 28 days based upon the toxicology then in existence. It is noteworthy that when study drug was discontinued after the 28-day pilot study patients regressed to baseline within one week whereas the proof of concept patients who had been on study drug for as long as 6 months maintained some

teachers and a school bus driver who were unaware of the trials.

residual benefit following the discontinuation of medication.

*L1-79 and the Role of Catecholamines in Autism DOI: http://dx.doi.org/10.5772/intechopen.95052*

#### **Figure 4.**

*Autism Spectrum Disorder - Profile, Heterogeneity, Neurobiology and Intervention*

*Proof of concept study: Connor parent rating scale (CPRS) at 4-week intervals for 8 participants. Some* 

*Proof of concept study: Autism diagnostic observation schedule (ADOS) scores for the 6 participants tested at* 

**112**

**Figure 3.**

**Figure 2.**

*participants did not have all assessments.*

*baseline and week 10.*

*Proof of concept study: Clinical global impressions (CGI) scores for 8 participants. Top panel shows absolute scores at week 1 and week 8. Bottom panel shows the change from week 1 to week 8. The qualitative interpretation at week 1 appears above each participant change in score, and the interpretation at week 8 is shown below each bar. Each participants efficacy index at week at appears at the bottom.*

he was still on the spectrum [236]. As can be seen in the ABC-C scores, these effects were observed rapidly.

A follow-up randomized, double blind, placebo-controlled 28-day study of 39 patients has been completed and the results are currently in preparation for publication [237]. While 28 days was too short to demonstrate much of an effect, per the FDA the existing toxicology did not permit a longer treatment duration at that time. Participants were male patients between the ages of 13 and 21 years of age with a diagnosis of ASD based on DSM-5 criteria and confirmed by Autistic Diagnosis Interview-Revised (ADI-R), ADOS and expert clinical opinion, stable on no more than one concomitant medication with no planned changes in psychosocial interventions during the study and sufficiently tolerant and capable of complying with the requirements for this study. Results from this brief study can be seen for the CGI (**Figure 5**), Social Response Scale-2 (SRS) social motivation T scores (**Figure 6**), ADOS (**Figure 7**), Vinland Adaptive Behavior Scale-II (VABS) socialization standard score (**Figure 8**), and the SRS DSM-SCI T scores (**Figure 9**).

Anecdotally, numerous salutary behaviors were observed in these studies. Two teenage boys hugged and kissed their parents for the first time. One teenager with a history of self mutilating behavior stopped hurting himself. Subjective aspects of socialization such as empathy, effective communication, emotional expression, better sleep patterns, and engagement with peers were reported by parents and teachers and a school bus driver who were unaware of the trials.

The proof of concept study was conducted under the assumption that, per the 505(b)(2) guidelines, any stereoisomer of a drug is considered to be the same drug, and therefore the use of L1-79 was an unapproved use of an approved agent (Demser). In subsequent discussions with the FDA this was disallowed. The FDA required that the proof of concept study be discontinued and approved a follow-on pilot study that was limited to 28 days based upon the toxicology then in existence. It is noteworthy that when study drug was discontinued after the 28-day pilot study patients regressed to baseline within one week whereas the proof of concept patients who had been on study drug for as long as 6 months maintained some residual benefit following the discontinuation of medication.

#### **Figure 5.**

*Pilot study: Change in clinical global impression-severity (CGI-S) over time and individual patient responses from baseline to week 4. Upper panel is the change over time by study week for L1-79 200 mg and placebo. The lower panel is individual patient responses for L1-79 200 mg and placebo.*

#### **Figure 6.**

*Change from baseline over time and individual patient responses in the social responsiveness Scale-2 (SRS-2) social motivation T-score at week 4. Upper panel is change from baseline over time for L1-79 200 mg and placebo. Lower panel is individual changes for L1-79 200 mg and placebo.*

**115**

**Figure 8.**

*for L1-79 200 mg and placebo.*

**Figure 7.**

*represent improvement.*

*L1-79 and the Role of Catecholamines in Autism DOI: http://dx.doi.org/10.5772/intechopen.95052*

*Pilot study: ADOS score changes for 200 mg dose and placebo after 28 days of treatment. Negative scores* 

*Upper panel: Change from baseline over time and individual patient responses Vineland adaptive behavior-II (VABS) socialization standard score at week 4 for L1-79 200 mg and placebo. Lower panel individual changes*  *L1-79 and the Role of Catecholamines in Autism DOI: http://dx.doi.org/10.5772/intechopen.95052*

#### **Figure 7.**

*Autism Spectrum Disorder - Profile, Heterogeneity, Neurobiology and Intervention*

*Pilot study: Change in clinical global impression-severity (CGI-S) over time and individual patient responses from baseline to week 4. Upper panel is the change over time by study week for L1-79 200 mg and placebo. The* 

*lower panel is individual patient responses for L1-79 200 mg and placebo.*

*Change from baseline over time and individual patient responses in the social responsiveness Scale-2 (SRS-2) social motivation T-score at week 4. Upper panel is change from baseline over time for L1-79 200 mg and* 

*placebo. Lower panel is individual changes for L1-79 200 mg and placebo.*

**114**

**Figure 6.**

**Figure 5.**

*Pilot study: ADOS score changes for 200 mg dose and placebo after 28 days of treatment. Negative scores represent improvement.*

#### **Figure 8.**

*Upper panel: Change from baseline over time and individual patient responses Vineland adaptive behavior-II (VABS) socialization standard score at week 4 for L1-79 200 mg and placebo. Lower panel individual changes for L1-79 200 mg and placebo.*

#### **Figure 9.**

*Pilot study: Upper panel is the change from baseline over time in the social responses scale – 2 DSM-SCI for week 4 L1-79 200 mg and placebo. Lower panel individual changes for L1-79 200 mg and placebo.*

#### **10. Mechanism of action**

We hypothesize that the mechanism begins with some process that stimulates massive levels of sympathetic neural traffic that gives rise to high levels of catecholamine synthesis and release which is associated with high levels of both BDNF and NGF [238]. NGF receptors are found on sympathetic nerves [239] and are responsible for maintaining catecholaminergic synaptic architecture due to their control on the budding and arborization of catecholamine dendrites [207, 208] and density of innervation [209, 210].

Elevated levels of synaptic nerve growth factors associated with catecholamine release may result from a variety of factors including genetics, cognitive or biological stress such as exposure to pesticides, fever in utero, complications of pregnancy, or other causes. This catecholamine elevation results in elevated levels of nerve traffic due to growth factor induced budding and arborization of catecholamine

**117**

literature**.**

*L1-79 and the Role of Catecholamines in Autism DOI: http://dx.doi.org/10.5772/intechopen.95052*

and metabolic pathology.

maintained by growth factors.

**11. Conclusions**

nerve terminals and collaterals. As these growth factors are required to support the dendritic architecture of the neurons over their life, this elevated level of NGF & BDNF become chronic, resulting in an enhanced level of synaptic morphology and a consequent elevation of catecholamine release from these new hypertrophic synapses. This change in the level of catecholaminergic tone and the elevated release of catecholamines creates a persistent imbalance in the CNS and between the sympathetic and parasympathetic arms of the autonomic nervous system resulting in an overstimulation of some tracts and depletion in others. This imbalance caused by the growth factors centrally and peripherally results in both neurologic

Because this involves catecholaminergic mechanisms in the brain, gut, mesentery, and elsewhere in the body, changes in emotional expression, speech, cognition, memory, circadian rhythms, gut function, energy metabolism, and the entire panoply of autism related symptoms can potentially be ascribed to aberrant catecholaminergic function. It is worth noting that NGF exerts presynaptic functionality with both pre- and post-synaptic effects with both short- and long-term effects on catecholaminergic neurotransmission [216]. Thus, the effects of L1-79 are not mimicked by receptor blocking agents which only reduce post-synaptic depolarization but do nothing to address the underlying abnormality of excessive catecholaminergic collaterals and a hypertrophic dendritic architecture induced and

Since NGF is known to stimulate TH [215, 240–242] and L1-79 inhibits TH, and given both the short and long term effects of NGF exposure on sympathetic substrates, L1-79 is likely to have a therapeutic effect in the short and intermediate term of treatment of autism and may even have a disease modifying effect in the long run if the hypertrophic synaptic architecture regresses to a more homeostatic morphology. That is, if the underlying pathology of ASD is due in whole or part due to elevated catecholaminergic tone due to the release of growth factors associated with catecholamine release, then by reducing catecholamine synthesis, storage and release along with the associated release of NGF and BDNF a reduction of symptoms is likely to result. If, over a longer period, the reduction of NGF and BDNF enables a restoration of normal synaptic morphology then a persistent reduction of

L1-79 inhibits the rate limiting step in the synthesis of catecholamine, including dopamine and norepinephrine. Unlike the L-isomer of AMPT (Demser), L1-79 has a better kinetic profile for the use of L1-79 as a treatment for ASD. It's presynaptic mechanism of action likely results in a diminution of both catecholamines and related growth factors which we hypothesize will reduce symptoms of ASD in a manner not possible with receptor blockers, and which with long term use may reduce the hypertrophic architecture of catecholamine synapses in ASD back to a homeostatic morphology. An exaggerated catecholaminergic mechanism underlying ASD and its associated comorbidities can explain a variety of potential influences on the disease including the effects of bile, orphan receptors, lipids, glucose and other factors. Preliminary results observed following the administration of L1-79 to autistic juveniles and adolescents has resulted in consistent improvement in the core symp-

L1-79 appears to be an effective therapy for the treatment of autism in children empirically with a novel mechanism of action that is supported by the scientific

ASD symptoms may be possible, even in the absence of treatment.

toms of in two early studies [214, 215] not seen with previous agents.

#### *L1-79 and the Role of Catecholamines in Autism DOI: http://dx.doi.org/10.5772/intechopen.95052*

*Autism Spectrum Disorder - Profile, Heterogeneity, Neurobiology and Intervention*

**116**

**10. Mechanism of action**

**Figure 9.**

of innervation [209, 210].

We hypothesize that the mechanism begins with some process that stimulates massive levels of sympathetic neural traffic that gives rise to high levels of catecholamine synthesis and release which is associated with high levels of both BDNF and NGF [238]. NGF receptors are found on sympathetic nerves [239] and are responsible for maintaining catecholaminergic synaptic architecture due to their control on the budding and arborization of catecholamine dendrites [207, 208] and density

*Pilot study: Upper panel is the change from baseline over time in the social responses scale – 2 DSM-SCI for week 4 L1-79 200 mg and placebo. Lower panel individual changes for L1-79 200 mg and placebo.*

Elevated levels of synaptic nerve growth factors associated with catecholamine release may result from a variety of factors including genetics, cognitive or biological stress such as exposure to pesticides, fever in utero, complications of pregnancy, or other causes. This catecholamine elevation results in elevated levels of nerve traffic due to growth factor induced budding and arborization of catecholamine

nerve terminals and collaterals. As these growth factors are required to support the dendritic architecture of the neurons over their life, this elevated level of NGF & BDNF become chronic, resulting in an enhanced level of synaptic morphology and a consequent elevation of catecholamine release from these new hypertrophic synapses. This change in the level of catecholaminergic tone and the elevated release of catecholamines creates a persistent imbalance in the CNS and between the sympathetic and parasympathetic arms of the autonomic nervous system resulting in an overstimulation of some tracts and depletion in others. This imbalance caused by the growth factors centrally and peripherally results in both neurologic and metabolic pathology.

Because this involves catecholaminergic mechanisms in the brain, gut, mesentery, and elsewhere in the body, changes in emotional expression, speech, cognition, memory, circadian rhythms, gut function, energy metabolism, and the entire panoply of autism related symptoms can potentially be ascribed to aberrant catecholaminergic function. It is worth noting that NGF exerts presynaptic functionality with both pre- and post-synaptic effects with both short- and long-term effects on catecholaminergic neurotransmission [216]. Thus, the effects of L1-79 are not mimicked by receptor blocking agents which only reduce post-synaptic depolarization but do nothing to address the underlying abnormality of excessive catecholaminergic collaterals and a hypertrophic dendritic architecture induced and maintained by growth factors.

Since NGF is known to stimulate TH [215, 240–242] and L1-79 inhibits TH, and given both the short and long term effects of NGF exposure on sympathetic substrates, L1-79 is likely to have a therapeutic effect in the short and intermediate term of treatment of autism and may even have a disease modifying effect in the long run if the hypertrophic synaptic architecture regresses to a more homeostatic morphology. That is, if the underlying pathology of ASD is due in whole or part due to elevated catecholaminergic tone due to the release of growth factors associated with catecholamine release, then by reducing catecholamine synthesis, storage and release along with the associated release of NGF and BDNF a reduction of symptoms is likely to result. If, over a longer period, the reduction of NGF and BDNF enables a restoration of normal synaptic morphology then a persistent reduction of ASD symptoms may be possible, even in the absence of treatment.
