Prevention of infantile spasms relapse: Zonisamide and topiramate provide no benefit

Outcomes following resective and disconnective strategies in the treatment of epileptic spasms: a systematic review of the literature and individual patient data meta-analysis

Epileptic spasms (ES) are a unique seizure type typically presenting in the form of infantile epileptic spasms syndrome (IESS) with characteristic hypsarrhythmia on scalp EEG and a preponderance with developmental delay or regression. While pharmacotherapy is the mainstay of treatment, surgical options, including disconnective or resective procedures, are increasingly recognized as viable therapeutic options for recurrent or persistent ES. However, limited data on safety, effectiveness, and prognostic factors hinder informed decision-making regarding surgery indications, timing, and intervention type. We performed a systematic review and an individual patient data meta-analysis (IPDMA) in accordance with PRISMA guidelines, focusing on surgical interventions for ES and reporting seizure outcomes using the Engel or ILAE scales. Twenty-six studies encompassing 358 ES patients undergoing resection/callosotomy were included. Participants undergoing other approaches (e.g., multiple subpial transections) or multimodality approaches were excluded from analysis. The median age at spasm onset was 6 months (IQR = 3.0-15.6), with a median age at surgery of 37 months (IQR = 17.2-76.8). Most patients (74.1%) exhibited additional seizure types. A total of 136 patients (35.8%) underwent corpus callosotomy (CC), of whom 125 (91.9%) had a complete callosotomy, while 11 (8.1%) had a partial callosotomy. Resective surgery was performed on 222 patients (58.4%). Among those who underwent resection, 109 (49.1%) had both lesional MRI findings and lateralized EEG abnormalities. Overall, 201 patients (56.1%) remained spasm-free at a median postoperative follow-up of 36 months (interquartile range, IQR = 21-60), including 52 (38.2%) from the callosotomy group and 149 (67.1%) from the resective surgery group. In the resective surgery cohort, patients with MRI-confirmed lesions (p = 0.026; HR = 0.53, 95% CI = 0.31-0.93) and those who underwent hemispherectomy (p = 0.026, HR = 0.46, 95% CI = 0.23-0.91) had better seizure outcomes. Only a minority (24.4%) underwent invasive EEG monitoring prior to ES surgery. Surgical treatment of ES proves effective, with two thirds of patients undergoing resective surgery and a third undergoing CC becoming spasm free. Post-operative developmental improvement was observed in 44 participants (65.7% of those with available data). The presence of lesional MRI and more extensive resection/disconnection (e.g., hemispherectomy) emerged as significant prognostic factors for spasm freedom and can inform clinical decision-making.

Computational EEG attributes predict response to therapy for epileptic spasms

OBJECTIVE

We set out to evaluate whether response to treatment for epileptic spasms is associated with specific candidate computational EEG biomarkers, independent of clinical attributes.

METHODS

We identified 50 children with epileptic spasms, with pre- and post-treatment overnight video-EEG. After EEG samples were preprocessed in an automated fashion to remove artifacts, we calculated amplitude, power spectrum, functional connectivity, entropy, and long-range temporal correlations (LRTCs). To evaluate the extent to which each feature is independently associated with response and relapse, we conducted logistic and proportional hazards regression, respectively.

RESULTS

After statistical adjustment for the duration of epileptic spasms prior to treatment, we observed an association between response and stronger baseline and post-treatment LRTCs (P = 0.042 and P = 0.004, respectively), and higher post-treatment entropy (P = 0.003). On an exploratory basis, freedom from relapse was associated with stronger post-treatment LRTCs (P = 0.006) and higher post-treatment entropy (P = 0.044).

CONCLUSION

This study suggests that multiple EEG features-especially LRTCs and entropy-may predict response and relapse.

SIGNIFICANCE

This study represents a step toward a more precise approach to measure and predict response to treatment for epileptic spasms.

Fifteen years of real-world data on the use of vigabatrin in individuals with infantile epileptic spasms syndrome

OBJECTIVE

This study was undertaken to evaluate our treatment algorithm for infantile epileptic spasms syndrome (IESS) used between 2000 and 2018. We initiated vigabatrin (VGB), and steroids were added if the electroclinical response (spasms and electroencephalogram [EEG]) to VGB was not obtained or incomplete.

METHODS

Individuals with IESS treated with VGB were recruited from our hospital clinical data warehouse based on electronic health records (EHRs) generated since 2009 and containing relevant keywords. We confirmed the diagnosis of IESS. Clinical, EEG, imaging, and biological data were extracted from the EHRs. We analyzed factors associated with short-term response, time to response, relapse, time to relapse of spasms, and the presence of spasms at last follow-up.

RESULTS

We collected data from 198 individuals (female: 46.5%, IESS onset: 6 [4.5-10.3] months, follow-up: 4.6 [2.5-7.6] years, median [Q1-Q3]) including 129 (65.2%) with identifiable etiology. VGB was started 17 (5-57.5) days after IESS diagnosis. A total of 113 individuals were responders (57.1% of the cohort), 64 with VGB alone and 38 with VGB further combined with steroids (56.6% and 33.6% of responders, respectively). Among responders, 33 (29%) experienced relapses of spasms, mostly those with later onset of spasms (p = .002) and those who received VGB for <24 months after spasms cessation compared to a longer duration on VGB (45% vs. 12.8%, p = .003). At follow-up, 92 individuals were seizure-free (46.5% of the whole cohort), including 26 free of therapy (13.1%). One hundred twelve individuals (56.6%) were still receiving VGB, with a duration of 3.2 (1.75-5.7) years.

SIGNIFICANCE

Our sequential protocol introducing VGB then adding steroids is an effective alternative to a combined VGB-steroids approach in IESS. It avoids steroid-related adverse events, as well as those from VGB-steroid combination. According to our data, a period of 7 days seems sufficient to assess VGB response and enables the addition of steroids rapidly if needed. Continuing VGB for 2 years may balance the risk of relapse and treatment-induced adverse events.

Assessing Risk for Relapse among Children with Infantile Spasms Using the Based Score after ACTH Treatment: A Retrospective Study

Introduction

Even though adrenocorticotropic hormone (ACTH) demonstrated powerful efficacy in the initially successful treatment of infantile spasms (IS), nearly one-half of patients whose spasms were once suppressed experienced relapse. There is currently no validated method for the prediction of the risk of relapse. The Burden of Amplitudes and Epileptiform Discharges (BASED) score is an electroencephalogram (EEG) grading scale for children with infantile spasms. We sought to determine whether an association exists between the BASED score after ACTH treatment and relapse after initial response with ACTH.

Methods

Children with IS who achieved initial response after ACTH treatment were selected as the study subjects. Those who experienced relapse within 12 months after ACTH treatment were categorized as the relapse group, and those who did not were categorized as the non-relapse group. Their general clinical data and EEG data (using BASED scoring) after ACTH treatment were collected, and compared between groups. Cox proportional hazards models were fit to determine factors associated with relapse.

Results

A total of 64 children with IS were enrolled in the study, of which 37 (57.8%) experienced a relapse, and the median duration after ACTH treatment was 3 (1.5, 6) months. The BASED score was significantly higher in the relapse group than in the non-relapse group. Cox modeling demonstrated that BASED score was independently associated with relapse. The patients with a score greater than or equal to 3 showed a high rate (89.3%) of relapse. The relapse group had stronger, more stable EEG functional networks than the non-relapse group, and there were obvious correlations between BASED score and functional connectivity.

Conclusion

This study suggests the BASED score after ACTH treatment has potential value as a predictor for relapse after initial response. Children with IS who have a BASED score greater than or equal to 3 after the initial response of ACTH carry a high risk of relapse within 1 year.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-022-00347-7.

Infantile spasms: assessing the diagnostic yield of an institutional guideline and the impact of etiology on long-term treatment response

OBJECTIVE

Neuroimaging and genetic testing have been proposed for diagnostic evaluation of infantile spasms (IS), establishing etiology in ~60% of multicenter IS cohorts. A retrospective analysis of the yield of diagnostic etiology following an institutionally established guideline for investigation/treatment of IS was conducted, and the association between etiological subgroups and sustained response to standard treatment was evaluated.

METHODS

Etiology of IS, neuroimaging, and genetic results were extracted from clinical records. Etiology was categorized as acquired or non-acquired, the latter including syndromic patients, non-syndromic patients with confirmed etiology, and unknown cases. Regression analyses, using clinical variables including subtypes of etiology, were conducted to determine which factors correlated with favorable (spasms freedom at last follow-up after ≤ 2 standard treatments) versus unfavorable treatment outcome (refractory spasms despite two standard treatments or relapse).

RESULTS

We included 127 IS patients (60% males) with a follow-up of 2.4 years (range 0.6-5 years). All patients had neuroimaging, and 95% of patients in the non-acquired category (103 of 108 patients) had genetic testing. Etiology was identified in 103/127 (81%, CI-0.73-0.86). At last follow-up, 42 (33%) patients had favorable treatment outcome. No difference in treatment response was observed between acquired and non-acquired etiologies. Among patients with non-acquired etiologies, developmental delay prior to spasms onset increased the odds of unfavorable treatment outcome (p=0.014) while a clearly recognizable dysmorphic/syndromic etiology was associated with a lower risk for treatment failure (p=0.034). In non-acquired etiology without a recognizable dysmorphic/syndrome but with a genetic etiology, unfavorable treatment outcome was more likely (p=0.043).

SIGNIFICANCE

Rigorous evaluation with neuroimaging and genetic testing yields an etiological diagnosis in most patients with IS. Among patients with a non-acquired etiology, those with recognizable dysmorphic/syndromic diagnosis had a higher likelihood of a favorable treatment outcome, while the absence of such a finding, when associated with an identifiable genetic diagnosis, was associated with unfavorable treatment outcomes.

Comparative Effectiveness of Initial Treatment for Infantile Spasms in a Contemporary US Cohort

OBJECTIVE

To compare the effectiveness of initial treatment for infantile spasms.

METHODS

The National Infantile Spasms Consortium prospectively followed up children with new-onset infantile spasms that began at age 2 to 24 months at 23 US centers (2012-2018). Freedom from treatment failure at 60 days required no second treatment for infantile spasms and no clinical spasms after 30 days of treatment initiation. We managed treatment selection bias with propensity score weighting and within-center correlation with generalized estimating equations.

RESULTS

Freedom from treatment failure rates were as follows: adrenocorticotropic hormone (ACTH) 88 of 190 (46%), oral steroids 42 of 95 (44%), vigabatrin 32 of 87 (37%), and nonstandard therapy 4 of 51 (8%). Changing from oral steroids to ACTH was not estimated to affect response (observed 44% estimated to change to 44% [95% confidence interval 34%-54%]). Changing from nonstandard therapy to ACTH would improve response from 8% to 39% (17%-67%), and changing to oral steroids would improve response from 8% to 38% (15%-68%). There were large but not statistically significant estimated effects of changing from vigabatrin to ACTH (29% to 42% [15%-75%]), from vigabatrin to oral steroids (29% to 42% [28%-57%]), and from nonstandard therapy to vigabatrin (8% to 20% [6%-50%]). Among children treated with vigabatrin, those with tuberous sclerosis complex (TSC) responded more often than others (62% vs 29%; p < 0.05).

DISCUSSION

Compared to nonstandard therapy, ACTH and oral steroids are superior for initial treatment of infantile spasms. The estimated effectiveness of vigabatrin is between that of ACTH/oral steroids and nonstandard therapy, although the sample was underpowered for statistical confidence. When used, vigabatrin worked best for TSC.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that for children with new-onset infantile spasms, ACTH or oral steroids were superior to nonstandard therapies.

Medication selection, health services outcomes, and cost trajectories for Medicaid beneficiaries with infantile spasms

OBJECTIVE

There are three recommended first-line treatments for infantile spasms, adrenocorticotropic hormone (ACTH), oral corticosteroids, and vigabatrin, though non-standard treatments such as topiramate are sometimes selected. Is it uncertain how treatment selection influences health services outcomes.

METHODS

We conducted a retrospective cohort study of Medicaid beneficiaries newly diagnosed with infantile spasms from 2009-2010. We included infants with a new diagnosis of infantile spasms between age 2-9 months who filled ACTH (reference), prednisolone, vigabatrin, or topiramate prescriptions. Multivariable Cox proportional hazards regression compared time to first emergency department (ED) visit or hospitalization across treatment groups during 2 years of follow-up. Monthly costs for each treatment were examined in 6-month intervals and compared in a multivariable generalized linear model.

RESULTS

Among 256 children with infantile spasms, 116 received ACTH, 62 prednisolone, 15 vigabatrin, and 63 topiramate. The rate of ED visit or hospitalization per person-year did not differ significantly for prednisolone (0.9 [95 % CI 0.7-1.2]; adjusted hazard ratio [aHR] 0.84, 95 % CI 0.57-1.24), vigabatrin (0.8 [95 % CI 0.4-1.5]; aHR 0.91, 95% CI 0.45-1.84), or topiramate (1.7 [95 % CI 1.3-2.3]; aHR 1.15, 95 % CI 0.80-1.65), when compared to ACTH (1.1 [95 % CI 0.9-1.3]). The median payment for ACTH was $96,406 (interquartile range 70,742-138,476) during the first 6 months. The adjusted mean total payment in the first 6 months was 73% lower for prednisolone (95% CI -82, -61), 69% lower for vigabatrin (95% CI -84, -40), and 73% lower for topiramate (95% CI -82, -59). However, in subsequent 6-month intervals, costs associated with ACTH were not significantly different compared to other treatments.

SIGNIFICANCE

Compared to other treatments for infantile spasms, use of ACTH was associated with greater cost in the first 6 months of treatment, but not with reduced ED visits or hospitalizations. The cost effectiveness of ACTH depends on its relative clinical efficacy, and merits additional research.

Efficacy, tolerability, and safety of zonisamide in children with epileptic spasms: A systematic review and meta-analysis

BACKGROUND

Valproate, levetiracetam, benzodiazepines, and topiramate are antiseizure medications (ASMs) considered to have definite efficacy in reducing the frequency of epileptic spasm frequency, apart from ketogenic dietary therapies. Although zonisamide has also been shown to have efficacy as second-line ASM for epileptic spasms, various studies have conflicting results in literature. This systematic review aims to summarize clinical studies regarding the efficacy of zonisamide for epileptic spasms.

METHODS

We conducted a systematic literature search collating all available literature. The primary objective was to determine efficacy in terms of proportion with complete spasm resolution, we also intended to determine proportion with at least 50% spasm reduction, hypsarrhythmia resolution, and nature/frequency of adverse effects. All prospective/retrospective, controlled/uncontrolled studies describing the use of zonisamide with epileptic spasms were included in the qualitative review excluding case reports, but for metanalysis pertaining to key outcomes, we included studies with at least 10 participants.

RESULTS

A total of nineteen publications were found eligible for inclusion in the qualitative review, out of 101 search items. A total of 401 children with epileptic spasms were tried up to a maximum of 9.9-35 mg/kg/day dose with only mild adverse effects in a few patients. Total 20.8% (95% CI-11.4%-29.2%) and 23.4% (95% CI-17.8%-29.1%) patients had complete cessation of spasms and at least a 50% reduction in total spasm frequency as compared to baseline after starting zonisamide. Similarly, 20.3% (95% CI-10.1%-30.5%) had resolution of hypsarrhythmia in EEG after starting zonisamide.

CONCLUSION

Zonisamide can reduce spasms in 21% of children with epileptic spasms, without major adverse effects. But there are only limited studies on epileptic spasms of sufficient quality to give high confidence in meta-analysis. Large controlled trials are needed in this regard to provide high-quality evidence favoring/disfavoring its use in patients with epileptic spasms.

Infantile Spasms: Outcome in Clinical Studies

Children with infantile spasms are likely to have a poor outcome. Outcome measures for infantile spasms include primary response to treatment, relapse of spasms, neurological development, death, and progression to another type of epilepsy (Consensus Statements of the WEST Delphi Group 2004). This review is based mainly on prospective studies and emphasizes data about the current first-line drugs, adrenocorticotropic hormone, vigabatrin, and prednisolone, taking into account the proportion of patients with known and unknown etiology, which has a very strong effect on seizure outcome. In most studies, hormonal treatment (adrenocorticotropic hormone or prednisolone) is the optimal monotherapy, except for patients with tuberous sclerosis complex, in whom vigabatrin appears superior. Combination therapy (hormones plus vigabatrin) may well be more effective than either agent alone. The underlying etiology is the most important prognostic factor. In studies with a long follow-up (up to 50 years), a favorable cognitive outcome has been observed in approximately one quarter of patients and complete seizure freedom in one-third. Autism is relatively frequent, and premature mortality is high throughout life. Modifiable prognostic factors include early recognition of the spasms with prompt treatment, short duration of hypsarrhythmia, prompt treatment of relapses of spasms and multifocal epileptic discharges, and early treatment of adverse effects. It is hoped that eventually advanced genetics and molecular data will allow an understanding of the pathogenetic mechanisms of many specific etiologies to allow disease-specific treatment such as is emerging for tuberous sclerosis.

Felbamate in the treatment of refractory epileptic spasms

Several small case series provide conflicting impressions of the efficacy of felbamate for treatment of epileptic spasms. Using a large single-center cohort of children with epileptic spasms, we retrospectively evaluated the efficacy and safety of felbamate. We identified all patients with video-EEG confirmed epileptic spasms who were treated with felbamate at our center. We quantified felbamate exposure by calculating peak and weighted-average weight-based dose. Clinical response was defined as resolution of epileptic spasms for at least 28 days, beginning not more than 3 months after felbamate initiation. Electroclinical response was defined as clinical response accompanied by overnight video-EEG demonstrating freedom from epileptic spasms and hypsarrhythmia. Among a cohort of 476 infants, we identified 62 children who were treated with felbamate, of whom 58 had previously failed treatment with hormonal therapy or vigabatrin. Median peak and weighted-average felbamate dosages were 47 and 40 mg/kg/day, respectively. Five (8%) children were classified as clinical responders and two (3%) children were classified as electroclinical responders. Among 17 patients with latency from epileptic spasms onset to felbamate initiation of less than 12 months, we observed 4 (24%) clinical responders. This study suggests that felbamate may be efficacious for treatment of epileptic spasms and that further rigorous study is warranted.

Limited efficacy of zonisamide in the treatment of refractory infantile spasms

A series of relatively small studies collectively suggest that zonisamide may be effective in the treatment of infantile spasms. Using a large single‐center cohort of children with infantile spasms, we set out to evaluate the efficacy and safety of zonisamide. We retrospectively identified all patients with infantile spasms who were treated with zonisamide at our center. For each patient, we recorded dates of birth, infantile spasms onset, response (if any), and most recent follow‐up. To quantify zonisamide exposure, we recorded daily dosage and patient weight at each sequential encounter so as to allow calculation of peak and weighted‐average weight‐based dosage. We identified 87 children who were treated with zonisamide, of whom 78 had previously been treated with hormonal therapy or vigabatrin. Peak and weighted‐average zonisamide dosage were 7.1 (interquartile range 3.6, 10.2) and 5.4 (interquartile range 3.0, 8.9) mg/kg/day, respectively. Whereas five (6%) patients exhibited resolution of epileptic spasms, only two (2%) patients exhibited video‐EEG confirmed resolution of both epileptic spasms and hypsarrhythmia (electroclinical response). Importantly, both electroclinical responders had not previously been treated with hormonal therapy or vigabatrin; in contrast, none of the 78 children with prior failure of hormonal therapy or vigabatrin subsequently responded to zonisamide. Zonisamide was well tolerated, and there were no deaths. This study suggests that zonisamide exhibits favorable tolerability but very limited efficacy among patients who do not respond to first‐line therapy.

Synthetic pharmaceutical grade cannabidiol for treatment of refractory infantile spasms: A multicenter phase-2 study

PURPOSE

Limited data suggest that cannabidiol (CBD) may be effective for treatment of refractory infantile spasms (IS). This study was designed to more rigorously evaluate the efficacy and safety of synthetic CBD in the treatment of IS.

METHODS

Children six to 36 months of age with IS that failed treatment with both adrenocorticotropic hormone (ACTH) and vigabatrin (VGB) were eligible for enrollment. Children receiving clobazam were excluded. After baseline overnight video-electroencephalography (vEEG) to confirm diagnosis and ascertain hypsarrhythmia, patients were treated with synthetic CBD oral solution (20 mg/kg/day). Overnight video-EEG was repeated after 14 days, and both baseline and repeat video-EEGs were completely de-identified and reviewed in a pairwise fashion by an independent, blinded pediatric electroencephalographer. The primary efficacy endpoint was freedom from spasms and hypsarrhythmia on day 14.

RESULTS

Nine patients were enrolled, comprising an older (median age = 23 months) cohort with long-standing IS (median duration = 13 months) and numerous prior treatment failures (median = 6). One patient responded to therapy and eight patients exhibited neither clinical nor electrographic response.

CONCLUSIONS

The immediate but temporary response in a single patient suggests that CBD oral solution is not particularly effective in highly refractory cases, but may, nevertheless, be effective in younger patients with shorter durations of IS. Further study, examining both short- and long-term outcomes, is warranted to further evaluate the efficacy and safety of CBD oral solution in the treatment of IS.

Optimized Treatment for Infantile Spasms: Vigabatrin versus Prednisolone versus Combination Therapy

Hormone therapies and vigabatrin are first-line agents in infantile spasms, but more than one-third of patients fail to respond to these treatments. This was a retrospective study of patients with infantile spasms who were treated between January 2005 and December 2017. We analyzed the response rates of initial treatment and second-line treatment. Responders were defined as those in whom cessation of spasms was observed for a period of at least one month, within 2 weeks of treatment initiation. Regarding the response rate to initial treatment, combination therapy of vigabatrin with prednisolone showed a significantly better response than that of vigabatrin monotherapy (55.3% vs. 39.1%, p = 0.037). Many drugs, such as clobazam, topiramate, and levetiracetam, were used as second-line agents after the failure of vigabatrin. Among these, no antiepileptic drug showed as good a response as prednisolone. For patients who used prednisolone, the proportion of responders was significantly higher in the higher-dose group (≥40 mg/day) than in the lower-dose group (66.7% vs. 12.5%, p = 0.028). Further studies of combination therapy to assess dosage protocols and long-term outcomes are needed.

Very-High-Dose Prednisolone Before ACTH for Treatment of Infantile Spasms: Evaluation of a Standardized Protocol

BACKGROUND

There is ongoing debate regarding the comparative effectiveness of adrenocorticotropic hormone and prednisolone in the treatment of infantile spasms. With a large cohort and extended follow-up, we set out to evaluate a protocol in which adrenocorticotropic hormone is reserved for prednisolone nonresponders.

METHODS

The following standardized hormonal therapy protocol was adopted. Patients initially receive prednisolone (8 mg/kg/day [maximum 60 mg/day], divided in three daily doses for 14 days). Prednisolone responders taper it over 14 days, whereas prednisolone nonresponders immediately transition to natural adrenocorticotropic hormone (150 U/m²/day, divided in two daily doses for 14 days). We evaluated short-term response, defined as video-electroenecphaloagraphy-confirmed resolution of both epileptic spasms and hypsarrhythmia on day 14, without relapse for 28 additional days. We then evaluated long-term relapse and calculated the rates of sustained response at six, 12, and 18 months.

RESULTS

We identified 102 children with infantile spasms who were treated with prednisolone. Prior exposure to hormonal therapy and vigabatrin was observed among 12% and 35% of patients, respectively. Sixty (59%) patients responded to prednisolone, and 13 (33%) prednisolone nonresponders then responded to adrenocorticotropic hormone. Cumulative response to prednisolone and adrenocorticotropic hormone (if needed) was higher among treatment-naive patients (84%) than among patients with prior exposure to first-line treatment (51%), with P < 0.001. Relapse was relatively common among all subgroups.

CONCLUSION

Short-term response to prednisolone was favorable and higher among treatment-naive patients. These data suggest that prednisolone is a reasonable approach to initial therapy and that adrenocorticotropic hormone exhibits substantial efficacy after prednisolone failure.

Treatment of infantile spasms

The treatment of infantile spasms is challenging, especially in the context of the following: (1) a severe phenotype with high morbidity and mortality; (2) the urgency of diagnosis and successful early response to therapy; and (3) the paucity of effective, safe, and well-tolerated therapies. Even after initially successful treatment, relapse risk is substantial and the most effective therapies pose considerable risk with long-term administration. In evaluating any treatment for infantile spasms, the key short-term outcome measure is freedom from both epileptic spasms and hypsarrhythmia. In contrast, the most important long-term outcomes are enduring seizure-freedom and measures of intellectual performance in later childhood and adulthood. First-line treatment options-namely hormonal therapy and vigabatrin-display moderate to high efficacy but also exhibit substantial side-effect burdens. Data on efficacy and safety of each class of therapy, as well as the combination of these therapies, are reviewed in detail. Specific hormonal therapies (adrenocorticotropic hormone and various corticosteroids) are contrasted. Those etiologies that prompt specific therapies are reviewed briefly, as are an array of second-line therapies supported by less-compelling data. The ketogenic diet is discussed in greater detail, with a focus on the limitations of numerous available studies that generally suggest that it is efficacious. Special discussion is allocated to cannabidiol-the investigational therapy that has received the most attention, and which is already in use in the form of various artisanal cannabis extracts. Finally, a treatment algorithm reflecting the concepts and controversies discussed in this review is presented.

High vigabatrin dosage is associated with lower risk of infantile spasms relapse among children with tuberous sclerosis complex

After initially successful treatment of infantile spasms, the long-term cumulative risk of relapse approaches 50%, and there is no established protocol to mitigate this risk. Although vigabatrin may be an effective means to prevent relapse, there is little guidance as to ideal duration and dosage. Using a cohort of children with infantile spasms and tuberous sclerosis complex (TSC), we evaluated the potential association of post-response VGB treatment and the rate of infantile spasms relapse. Patients with infantile spasms and clinical response to vigabatrin were identified among a multicenter prospective observational cohort of children with TSC. For each patient we recorded dates of infantile spasms onset, response to vigabatrin, relapse (if any), and quantified duration and dosage of vigabatrin after response. Time to relapse as a function of vigabatrin exposure was evaluated using survival analyses. We identified 50 children who responded to VGB. During a median follow-up of 16.6 months (IQR 10.3-22.9), 12 (24%) patients subsequently relapsed after a median of 7.8 months (IQR 3.1-9.6). Relapse occurred after VGB discontinuation in four patients, and during continued VGB treatment in the remaining eight cases. In survival analyses, risk of relapse was unaffected by the presence or absence of VGB treatment (HR 0.31, 95%CI 0.01-28.4, P =  0.61), but weighted-average dosage was associated with marked reduction in relapse risk: Each 50 mg/kg/d increment in dosage was associated with 61% reduction in risk (HR 0.39, 95%CI 0.17 - 0.90, P =  0.026). This study suggests that the risk of infantile spasms relapse in TSC may be reduced by high-dose vigabatrin treatment.

Improving Outcomes in Infantile Spasms: Role of Pharmacotherapy

Infantile spasms, and specifically within the context of West syndrome , is one of the most common epileptic encephalopathies to occur in early infancy. Early recognition and treatment can improve neurodevelopmental outcome in some cases, although the underlying aetiology is probably the most important prognostic factor in both spasm suppression and developmental outcome. Corticosteroids, either adrenocorticotrophic hormone (ACTH) or prednisolone, and vigabatrin are currently the preferred first-line treatment options. Vigabatrin is the treatment of choice when the underlying cause is tuberous sclerosis complex (TSC). Emerging evidence suggests that a combination of steroid and vigabatrin may be more effective in the suppression of spasms and resolution of hypsarrhythmia, the electro-encephalographic signal of spasms. Several other anti-epileptic drugs (AEDs) (levetiracetam, nitrazepam, sodium valproate, topiramate, zonisamide) are usually used as add-on or adjunctive treatment in refractory cases. Pyridoxine (or pyridoxal phosphate) and the ketogenic diet are established treatment options in refractory cases. There is some evidence that neuro-active steroids, including ganaxolone, may be effective; however, clinical trials undertaken intermittently for over a decade have yet to prove their efficacy, not only for the suppression of infantile spasms but also for the resolution of hypsarrhythmia, which may be as important as seizure control in developmental outcome in these children. Insights into developing novel treatment options have emerged from rodent models of infantile spasms, and research is continuing into the efficacy of rapamycin in improving outcomes in infantile spasms. This review provides a brief overview of the existing scientific literature around treatment options and outlines emerging newer treatment options in infantile spasms.