Evaluation of the risk of liver damage from the use of 5-aminolevulinic acid for intra-operative identification and resection in patients with malignant gliomas

Noninvasive Ultra Low Intensity Light Photodynamic Treatment of Glioblastoma with Drug Augmentation: LoGlo PDT Regimen

This paper presents the basis for LoGlo PDT, a new treatment for glioblastoma. Glioblastoma is currently treated with maximal safe resection, temozolomide, and ionizing irradiation. Mortality in 2024 remains over 80% within several years from diagnosis. Oral 5-aminolevulinic acid (5-ALA) is an FDA/EMA approved drug that is selectively taken up by malignant cells, including by glioblastoma. In photodynamic treatment of glioblastoma, intense intraoperative light causes glioblastoma tissue that has taken up 5-ALA to generate cytotoxic reactive oxygen species. The requirement for intense light flux has restricted photodynamic treatment to a single one-hour intraoperative session. We analyze here published data showing that external light, illuminating the entire intact scalp, can attain low μW/cm2 flux several cm into intact brain that would be sufficient to mediate 5-ALA photodynamic treatment of glioblastoma if the light and 5-ALA are delivered continuously over 24 h. At the core of LoGlo PDT regimen is the dataset showing that, for a given fluence, as the duration of PDT light delivery goes down, light intensity (flux) delivered must go up to achieve the same glioblastoma cell cytotoxicity as would a weaker light (lower flux) delivered over a longer time. Thus, a repetitive, noninvasive PDT of glioblastoma using an external light source may be possible. We analyze 5-ALA cellular physiology to show that three non-oncology drugs, ciprofloxacin, deferiprone, and telmisartan, can be repurposed to increase light energy capture after 5-ALA, thereby increasing photodynamic treatment's glioblastoma cell cytotoxicity. The LoGlo PDT approach uses both drug augmentation and prolonged ultra-low noninvasive transcranial light delivery for a repetitive, noninvasive 5-ALA photodynamic treatment of glioblastoma.

5-Aminolevulonic Acid, a New Tumor Contrast Agent: Anesthesia Considerations in Patients Undergoing Craniotomy

5-aminolevulinic acid (ALA) is used during resection of malignant gliomas due to its fluorescence properties and has been shown to render resection more effective than resection without ALA guidance. The aim of this narrative review is to categorize the adverse effects of ALA relevant to anesthesia providers. Intraoperative hypotension, porphyria-related side effects, alterations in blood chemistry and coagulation, photosensitivity, and increased levels of liver enzymes have all been reported. We also sought to examine the impact of dosage and timing of oral administration on efficacy of ALA and on these side effects. Twenty-seven studies met our inclusion criteria of patients undergoing craniotomy for glioma resection using ALA and occurrence of at least one adverse effect. The results of these studies showed that there was heterogeneity in levels of intraoperative hypotension, with some reporting an incidence as high as 32%, and that hypotension was associated with antihypertensive medication use. Clinical symptoms of porphyria, such as gastrointestinal disturbance, were less commonly reported. Photosensitivity of the skin after 5-ALA administration was well documented particularly in patients exposed to light; however, adverse effects on the eye were not adequately studied. Elevation in liver enzymes was a common finding postoperatively but was often clinically insignificant. The timing of oral administration presents practical issues for the preoperative management of patients undergoing resection with ALA. We provide guidance for perioperative management of patients who receive ALA for brain tumor resection. Controlled studies with adequate statistical power are required to further understand and prevent the adverse effects of ALA.

The Safety of Intraoperative Photodynamic Diagnosis Using 5-Aminolevulinic Acid Combined with Talaporfin Sodium Photodynamic Therapy in Recurrent High-Grade Glioma

BACKGROUND

Intraoperative photodynamic diagnosis (PDD) using 5-aminolevulinic acid (5-ALA) is a widely adopted technique to enhance the extent of resection during high-grade glioma (HGG) surgery. Recent updates to the package insert for 5-ALA in Japan now allow its use in combination with drugs that may induce photosensitivity, such as talaporfin sodium (TS). TS is employed in intraoperative photodynamic therapy (PDT) and has been shown to improve overall survival. The combination of 5-ALA with TS is expected to offer further benefits. However, the safety of this combination had not been established. This study reports on the safety of 5-ALA-PDD with TS-PDT in the treatment of recurrent HGG.

METHODS

7 patients with recurrent HGG underwent tumor resection using a combination of 5-ALA-PDD and TS-PDT. The incidence of photosensitivity as an adverse effect associated with 5-ALA and TS was evaluated as described in the package insert. Adverse events were assessed according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.

RESULTS

Tumor-specific fluorescence intensity was strong in 4 cases and weak in 3. Photosensitivity occurred in only 1 patient (14.3%). Three patients exhibited CTCAE grade 1 or 2 abnormal liver function, and 1 patient experienced CTCAE grade 1 γ-GTP elevation. All abnormalities improved during follow-up.

CONCLUSIONS

The combined use of 5-ALA-PDD and TS-PDT for HGG surgery did not increase the risk of serious adverse events in our study. Further investigations with a larger number of cases are needed for a more accurate assessment of its safety and efficacy.

Keeping patients in the dark: perioperative anesthetic considerations for patients receiving 5-aminolevulinic acid for glioma resection

PURPOSE OF REVIEW

5-Aminolevulinic acid hydrochloride (5-ALA), available under the trade name Gleolan, is an orally administered fluorophore drug used to enhance visual differentiation of cancerous tissue from healthy tissue, primarily during surgical resection of high-grade gliomas. Although given preoperatively, 5-ALA has important implications for anesthetic care throughout the perioperative period. This article reviews pharmacology, safety concerns, and perioperative considerations for patients who receive oral 5-ALA.

RECENT FINDINGS

Although approved for clinical use by the United States Food and Drug Administration in 2017, studies and case reports published since then have further delineated side effects of this medication and its mechanisms and pharmacokinetics.

SUMMARY

Mitigating the possible side effects of 5-ALA requires an understanding of its basic mechanism as well as focused perioperative planning and communication. Administration of this medication may result in nausea, vomiting, photosensitivity, increase in serum concentration of liver enzymes, and hypotension. Patients who receive 5-ALA must be protected from prolonged light exposure during the first 48 h after consumption and administration of other photosensitizing agents should be avoided (Supplemental Video File/Video abstract).

Spontaneous intracerebral haemorrhage secondary to 5-ALA-induced thrombocytopaenia in a paediatric patient: case report and literature review

INTRODUCTION

The primary objective of neurosurgical management of malignant gliomas is maximal safe resection of the tumour. One of the main obstacles in achieving this is the ability to accurately discriminate between tumour edges and the surrounding healthy brain tissue. The use of fluorescence-guided surgery utilising 5-aminolevulinic acid (5-ALA), first introduced more than 20 years ago, has become an invaluable adjunct in high-grade glioma surgery in adults. However, as 5-ALA is not licensed for use in paediatric patients, the safety profile for such use remains undetermined.

CASE REPORT

We describe the case of a 4-year-old boy who underwent 5-ALA-guided resection of a fourth ventricle anaplastic ependymoma. Although complete resection was achieved and the patient awoke from surgery well with no neurological deficits, the patient developed acute transaminitis, anaemia, thrombocytopaenia and coagulopathy postoperatively. The patient had a sudden neurological deterioration on postoperative day 2; imaging revealed that he had suffered a spontaneous right frontal intracerebral haemorrhage. The patient returned to theatre for surgical decompression and evacuation of the haematoma, and ultimately went on to make a full recovery.

CONCLUSION

The use of 5-ALA in paediatric patients can be helpful in maximising surgical resection, but the associated safety profile remains undefined. Further research is urgently warranted in order to characterise the efficacy and risk of the use of 5-ALA in the paediatric population.

In Vivo Study of the Efficacy and Safety of 5-Aminolevulinic Radiodynamic Therapy for Glioblastoma Fractionated Radiotherapy

To treat malignant glioma, standard fractionated radiotherapy (RT; 60 Gy/30 fractions over 6 weeks) was performed post-surgery in combination with temozolomide to improve overall survival. Malignant glioblastoma recurrence rate is extremely high, and most recurrent tumors originate from the excision cavity in the high-dose irradiation region. In our previous study, protoporphyrin IX physicochemically enhanced reactive oxygen species generation by ionizing radiation and combined treatment with 5-aminolevulinic acid (5-ALA) and ionizing radiation, while radiodynamic therapy (RDT) improved tumor growth suppression in vivo in a melanoma mouse model. We examined the effect of 5-ALA RDT on the standard fractionated RT protocol using U251MG- or U87MG-bearing mice. 5-ALA was orally administered at 60 or 120 mg/kg, 4 h prior to irradiation. In both models, combined treatment with 5-ALA slowed tumor progression and promoted regression compared to treatment with ionizing radiation alone. The standard fractionated RT protocol of 60 Gy in 30 fractions with oral administration of 120 and 240 mg/kg 5-ALA, the human equivalent dose of photodynamic diagnosis, revealed no significant increase in toxicity to normal skin or brain tissue compared to ionizing radiation alone. Thus, RDT is expected to enhance RT treatment of glioblastoma without severe toxicity under clinically feasible conditions.

Chimeric Mouse With Humanized Liver Is an Appropriate Animal Model to Investigate Mode of Action for Porphyria-Mediated Hepatocytotoxicity

Porphyrinogenic compounds are known to induce porphyria-mediated hepatocellular injury and subsequent regenerative proliferation in rodents, ultimately leading to hepatocellular tumor induction. However, an appropriate in vivo experimental model to evaluate an effect of porphyrinogenic compounds on human liver has not been fully established. Recently, the chimeric mouse with humanized liver (PXB mice) became widely used as a humanized model in which human hepatocytes are transplanted. In the present study, we examined the utility of PXB mice as an in vivo experimental model to evaluate the key events of the porphyria-mediated cytotoxicity mode of action (MOA) in humans. The treatment of PXB mice with 5-aminolevulinic acid, a representative porphyrinogenic compound, for 28 days caused protoporphyrin IX accumulation, followed by hepatocyte necrosis, increased mitosis, and an increase in replicative DNA synthesis in human hepatocytes, indicative of cellular injury and regenerative proliferation, similar to findings in patients with porphyria or experimental porphyria models and corresponding to the key events of the MOA for porphyria-mediated hepatocellular carcinogenesis. We conclude that the PXB mouse is a useful model to evaluate the key events of the porphyria-mediated cytotoxicity MOA in humans and suggest the utility of PXB mice for clarifying the human relevancy of findings in mice.

Fluorescence-Guided Surgery: A Review on Timing and Use in Brain Tumor Surgery

Fluorescence-guided surgery (FGS) allows surgeons to have improved visualization of tumor tissue in the operating room, enabling maximal safe resection of malignant brain tumors. Over the past two decades, multiple fluorescent agents have been studied for FGS, including 5-aminolevulinic acid (5-ALA), fluorescein sodium, and indocyanine green (ICG). Both non-targeted and targeted fluorescent agents are currently being used in clinical practice, as well as under investigation, for glioma visualization and resection. While the efficacy of intraoperative fluorescence in studied fluorophores has been well established in the literature, the effect of timing on fluorophore administration in glioma surgery has not been as well depicted. In the past year, recent studies of 5-ALA use have shown that intraoperative fluorescence may persist beyond the previously studied window used in prior multicenter trials. Additionally, the use of fluorophores for different brain tumor types is discussed in detail, including a discussion of choosing the right fluorophore based on tumor etiology. In the following review, the authors will describe the temporal nature of the various fluorophores used in glioma surgery, what remains uncertain in FGS, and provide a guide for using fluorescence as a surgical adjunct in brain tumor surgery.

Development of a Prodrug of Camptothecin for Enhanced Treatment of Glioblastoma Multiforme

A novel therapeutic approach for glioblastoma multiforme (GBM) therapy has been carried out through in vitro and in vivo testing by using the prodrug camptothecin-20-O-(5-aminolevulinate) (CPT-ALA). The incorporation of ALA to CPT may promote uptake of the cytotoxic molecule by glioblastoma cells where the heme synthesis pathway is active, improving the therapeutic action and reducing the side effects over healthy tissue. The antitumor properties of CPT-ALA have been tested on different GBM cell lines (U87, U251, and C6) as well as in an orthotopic GBM model in rat, where potential toxicity in central nervous system cells was analyzed. In vitro results indicated no significant differences in the cytotoxic effect over the different GBM cell lines for CPT and CPT-ALA, albeit cell mortality induced by CPT over normal cell lines was significantly higher than CPT-ALA. Moreover, intracranial GBM in rat was significantly reduced (30% volume) with 2 weeks of CPT-ALA treatment with no significant side effects or alterations to the well-being of the animals tested. 5-ALA moiety enhances CPT diffusion into tumors due to solubility improvement and its metabolic-based targeting, increasing the CPT cytotoxic effect on malignant cells while reducing CPT diffusion to other proliferative healthy tissue. We demonstrate that CPT-ALA blocks proliferation of GBM cells, reducing the infiltrative capacity of GBM and promoting the success of surgical removal, which improves life expectancy by reducing tumor recurrence.

Detailed analysis of 5-aminolevulinic acid induced fluorescence in different brain metastases at two specialized neurosurgical centers: experience in 157 cases

OBJECTIVE

Incomplete neurosurgical resection of brain metastases (BM) due to insufficient intraoperative visualization of tumor tissue is a major clinical challenge and might result in local recurrence. Recently, visible 5-aminolevulinic acid (5-ALA) induced fluorescence was first reported in patients with BM. The aim of this study was thus to investigate, for the first time systematically, the value of 5-ALA fluorescence for intraoperative visualization of BM in a large patient cohort.

METHODS

Adult patients (≥ 18 years) with resection of suspected BM after preoperative 5-ALA administration were prospectively recruited at two specialized neurosurgical centers. During surgery, the fluorescence status (visible or no fluorescence); fluorescence quality (strong, vague, or none); and fluorescence homogeneity (homogeneous or heterogeneous) of each BM was investigated. Additionally, these specific fluorescence characteristics of BM were correlated with the primary tumor type and the histopathological subtype. Tumor diagnosis was established according to the current WHO 2016 criteria.

RESULTS

Altogether, 157 BM were surgically treated in 154 patients. Visible fluorescence was observed in 104 BM (66%), whereas fluorescence was absent in the remaining 53 cases (34%). In detail, 53 tumors (34%) showed strong fluorescence, 51 tumors (32%) showed vague fluorescence, and 53 tumors (34%) had no fluorescence. The majority of BM (84% of cases) demonstrated a heterogeneous fluorescence pattern. According to primary tumor, visible fluorescence was less frequent in BM of melanomas compared to all other tumors (p = 0.037). According to histopathological subtype, visible fluorescence was more common in BM of ductal breast cancer than all other subtypes (p = 0.008). It is of note that visible fluorescence was observed in the surrounding brain tissue after the resection of BM in 74 (67%) of 111 investigated cases as well.

CONCLUSIONS

In this largest series to date, visible 5-ALA fluorescence was detected in two-thirds of BM. However, the characteristic heterogeneous fluorescence pattern and frequent lack of strong fluorescence limits the use of 5-ALA in BM and thus this technique needs further improvements.

Preoperative 5-aminolevulinic acid administration for brain tumor surgery is associated with an increase in postoperative liver enzymes: a retrospective cohort study

BACKGROUND

Besides 5-aminolevulinic acid (5-ALA), liver enzyme elevation after brain tumor surgery can be caused by anesthesia and medications. In this retrospective study, we determined whether preoperative 5-ALA administration is associated with postoperative elevation of liver enzymes (PELE) in brain tumor patients and identified predictive factors for PELE in patients treated with 5-ALA.

METHODS

In 179 patients undergoing brain tumor surgery with preoperative normal values of liver enzymes, laboratory data on serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and total bilirubin (T.bil) levels were collected preoperatively and through postoperative day (POD) 45.

RESULTS

Ninety-nine PELEs (ALT, 56; AST, 34; ALP, 5; and TB, 4) were observed in 62 (34.6%) patients. Four (4.2%) patients treated with 5-ALA showed grade 3 elevation of transaminases based on the Common Terminology Criteria for Adverse Effects. Preoperative 5-ALA treatment was predictive of PELE (odds ratio [95% confidence interval], 2.30 [1.14-4.67]; P = 0.021). In patients treated with 5-ALA (n = 95), 70 PELEs (ALT, 39; AST, 22; ALP, 5; and TB, 4) were observed in 41 (43.2%) patients and significant predictive factors for PELE were preoperative ALT level (1.10 [1.04-1.17]; P = 0.001) and body mass index (BMI, 1.29 [1.08-1.56]; P = 0.006). In patients treated with 5-ALA, 13 and 36 patients, of 39 patients whose maximum postoperative ALT levels > 40 U/L, showed the normal value of serum ALT on PODs 14 and 45, respectively. Only three patients showed ALT elevation > 40 U/L on PODs 15-45, with a downward trend.

CONCLUSIONS

The use of 5-ALA for brain tumor surgery in patients with preoperative normal values of liver enzymes was associated with increased transient PELE, but a low incidence of severely elevated liver transaminases levels. When 5-ALA is administered to patients with the upper normal value of preoperative serum ALT and overweight, attention is paid to PELE.

Effects of preoperative 5-aminolevulinic acid administration on postoperative liver enzymes after brain tumor surgery in patients with elevated preoperative liver enzymes

The effect of 5-aminolevulinic acid (5-ALA) on a postoperative increase in liver enzymes (PILE) has not been clearly investigated in patients with elevated preoperative liver enzymes. The aim of this study was to evaluate the safety of 5-ALA in brain tumor patients with elevated preoperative liver enzymes by investigating the incidence, severity, and duration of PILE. This retrospective study was conducted in patients with a brain tumor who received 5-ALA preoperatively and had a preoperative increase in liver enzymes. Laboratory data on serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and total bilirubin (TB) levels were collected preoperatively and through postoperative day (POD) 30. The incidence and severity of PILE was evaluated based on the Common Terminology Criteria for Adverse Events. Among 134 patients, 61 (45.5%) developed 97 episodes (grade 1/2/3: 80/10/7) of PILE. Postoperative increases in ALT, AST, ALP, and TB were observed in 41 (30.6%), 33 (24.6%), 6 (4.5%), and 17 (12.7%) patients respectively. Five (3.7%) and two (1.5%) patients showed grade 3 increases in ALT and AST respectively. The maximum liver enzyme levels shown in 97 episodes resolved to preoperative baseline or normal (n = 70), grade 1 (n = 24), and grade 2 (n = 3) levels within POD 30. The incidence of PILE after 5-ALA-guided brain tumor surgery in patients with increased preoperative liver enzymes was 45.5%. However, most PILEs were temporary and the incidence of severe PILE was low, suggesting that administering 5-ALA is relatively safe even in patients with elevated preoperative liver enzymes.