Drug interactions may be important risk factors for methotrexate neurotoxicity, particularly in pediatric leukemia patients

The Role of Cobalamin in Multiple Sclerosis: An Update

Multiple sclerosis (MS) is a neurodegenerative condition that results in axonal and permanent damage to the central nervous system, necessitating healing owing to autoimmune reactions and persistent neuroinflammation. Antioxidant and anti-inflammatory drugs are essential for the management of oxidative stress and neuroinflammation. Additionally, multivitamin supplementation, particularly vitamin B12 (cobalamin), may be beneficial for neuronal protection. Although there is no documented connection between vitamin B12 deficiency and MS, researchers have explored its potential as a metabolic cause. This review highlights the therapeutic benefits of cobalamin (Cbl) in patients with MS.

Is Methotrexate Ototoxic? Investigating the Ototoxic Late Effects of Pediatric Cancer Treatment

PURPOSE

Pediatric cancer survivors often experience long-term adverse health conditions or late effects, including hearing loss, that are attributable to cancer therapy. Ototoxic late effects have been documented in patients with cancer treated with cisplatin-based chemotherapy and/or radiation. This study evaluated the late effects of methotrexate as compared to cisplatin and other cancer therapy agents on pediatric cancer survivors at the Children's Hospital of New Orleans in Louisiana (CHNOLA) and patients currently undergoing cancer treatment at Our Lady of the Lake (OLOL) Hospital in Baton Rouge, Louisiana.

METHOD

A retrospective chart review was conducted of medical records from the CHNOLA Audiology Clinic and the Treatment After Cancer Late Effects clinic, which followed patients 2-19 years after cancer treatment completion and current patients with pediatric cancer at OLOL. This study identified pediatric cancer survivors between 2 and 24 years of age with treatment protocol information and audiological evaluations. Association studies were performed to calculate p values using an exact chi-square test.

RESULTS

More than 44% of late-effects patients had significant hearing loss; mild-to-profound hearing loss was observed in 37.5% of patients who received methotrexate treatment without cisplatin or irradiation. Eighty-three percent of the patients who received cisplatin had late-effect hearing loss. In patients currently receiving cancer treatment, 12% had significant hearing loss.

CONCLUSIONS

The results from this study suggest that children who receive therapies not clinically established as ototoxic (i.e., methotrexate) may still be at a high risk of developing long-term hearing loss as a late effect. Due to the high incidence rate of hearing loss among patients with pediatric cancer, we recommend that audiologists be part of the late-effects care team. This study also demonstrates that patients with pediatric cancer treated with methotrexate should receive routine long-term auditory monitoring as part of their standard of care to detect and manage hearing loss early, minimizing adverse outcomes.

Mechanisms of action of vitamin B1 (thiamine), B6 (pyridoxine), and B12 (cobalamin) in pain: a narrative review

Pain is a complex sensory and emotional experience with nociceptive, nociplastic, and neuropathic components. An involvement of neurotropic B vitamins (B1 - thiamine, B6 - pyridoxine, and B12 - cyanocobalamin) as modulators of inflammation and pain has been long discussed. New evidence suggests their therapeutic potential in different pain conditions. In this review, we discuss the main role of neurotropic B vitamins on different nociceptive pathways in the nervous system and to describe their analgesic action mechanisms. The performed literature review showed that, through different mechanisms, these vitamins regulate several inflammatory and neural mediators in nociceptive and neuropathic pain. Some of these processes include aiming the activation of the descending pain modulatory system and in specific intracellular pathways, anti-inflammatory, antioxidative and nerve regenerative effects. Moreover, recent data shows the antinociceptive, antiallodynic, and anti-hyperalgesic effects of the combination of these vitamins, as well as their synergistic effects with known analgesics. Understanding how vitamins B1, B6, and B12 affect several nociceptive mechanisms can therefore be of significance in the treatment of various pain conditions.

Intrathecal Methotrexate Toxicity Resulting in Brain Death due to Generalized Cerebral Edema Case Report

Intrathecal methotrexate (IT MTX) resulting in severe adverse events including life-threatening cerebral edema is not well described. We report a rare case of death in a 37-year-old BRCA1+ woman with metastatic triple-negative breast cancer status post mastectomy following administration of IT MTX for leptomeningeal carcinomatosis. Within the 24 hours after intraoperative IT MTX delivery, she developed neurologically devastating diffuse cerebral edema leading to uncal and cerebellar tonsillar herniation. This case report highlights a rare but devastating side effect of IT MTX.

Supportive methods for childhood acute lymphoblastic leukemia then and now: A compilation for clinical practice

Survival of childhood acute lymphoblastic leukemia has significantly improved over the past decades. In the early years of chemotherapeutic development, improvement in survival rates could be attained only by increasing the cytostatic dose, also by modulation of the frequency and combination of chemotherapeutic agents associated with severe short- and long-time side-effects and toxicity in a developing child's organism. Years later, new treatment options have yielded promising results through targeted immune and molecular drugs, especially in relapsed and refractory leukemia, and are continuously added to conventional therapy or even replace first-line treatment. Compared to conventional strategies, these new therapies have different side-effects, requiring special supportive measures. Supportive treatment includes the prevention of serious acute and sometimes life-threatening events as well as managing therapy-related long-term side-effects and preemptive treatment of complications and is thus mandatory for successful oncological therapy. Inadequate supportive therapy is still one of the main causes of treatment failure, mortality, poor quality of life, and unsatisfactory long-term outcome in children with acute lymphoblastic leukemia. But nowadays it is a challenge to find a way through the flood of supportive recommendations and guidelines that are available in the literature. Furthermore, the development of new therapies for childhood leukemia has changed the range of supportive methods and must be observed in addition to conventional recommendations. This review aims to provide a clear and recent compilation of the most important supportive methods in the field of childhood leukemia, based on conventional regimes as well as the most promising new therapeutic approaches to date.

Mini-Review: Aplastic Myelin Following Chemotherapy

The contribution of chemotherapy to improved outcomes for cancer patients is unquestionable. Yet as its applications broaden, so do the concerns for the long-term implications of chemotherapy on the health of cancer survivors, with chemotherapy-related cognitive impairment as a cause for particular urgency. In this mini review, we explore myelin aplasticity following chemotherapy, discussing the role of myelin plasticity in healthy cognition and failure of myelin plasticity chiefly due microenvironmental aberrations in chemotherapy-related cognitive impairment. Possible therapeutic strategies to mitigate chemotherapy-induced myelin dysfunction are also discussed.

A natural history study of nitrous oxide versus propofol-assisted intrathecal therapy in the treatment of acute lymphoblastic leukemia

BACKGROUND

Childhood acute lymphoblastic leukemia (ALL) treatment requires numerous lumbar punctures (LPs) with intrathecal (IT) chemotherapy to prevent and treat central nervous system disease. Historically, LPs in this setting are performed using propofol sedation at most institutions. At our center, LPs are often alternatively performed under nitrous oxide (N₂ O). To date, there have been no large-scale assessments comparing these sedation methods for this purpose.

PROCEDURES

Retrospective cohort study of patients aged 0-31 years with ALL treated between January 1, 2013 and December 31, 2018 at the Children's Minnesota Cancer and Blood Disorders Center, including all therapeutic LPs performed in the clinic setting under either propofol or N₂ O.

RESULTS

Among 215 patients and 2677 therapeutic LPs, 56.6% (n = 1515) occurred under N₂ O, with 43.3% (n = 93) of patients using exclusively N₂ O with all LPs. The incidence of traumatic LPs (red blood cell [RBC] ≥10 cells/μl) was similar between both treatments (27.3% vs. 30.2%). Successful IT chemotherapy delivery (99.7% N₂ O vs. 99.8% propofol) did not differ between sedation types. Experiencing a traumatic LP under N₂ O was associated with a sedation switch for the subsequent LP (adjusted odds ratio [aOR] 2.40, p = .002), whereas older age (aOR 1.08, p < .0001) and higher body mass index (BMI) percentile (aOR 1.01, p = .009) were associated with increased likelihood for undergoing a traumatic LP.

CONCLUSION

N₂ O is an effective sedation option for therapeutic LPs in children with ALL with noninferiority to propofol in terms of IT chemotherapy administration and traumatic LP incidence. For many patients, N₂ O can effectively replace propofol during LP procedures, which has important safety and quality-of-life implications.

[Role of B vitamins, thiamine, pyridoxine, and cyanocobalamin in back pain and other musculoskeletal conditions: a narrative review]

Low back pain, as well as other musculoskeletal disorders (neck pain, osteoarthritis, etc.), are a very frequent cause of consultation both in primary care and in other hospital specialties and are usually associated with high functional and work disability. Acute low back pain can present different nociceptive, neuropathic and nonciplastic components, which leads to consider it as a mixed type pain. The importance of the concept of mixed pain is due to the fact that the symptomatic relief of these pathologies requires a multimodal therapeutic approach to various pharmacological targets. The antinociceptive role of the B vitamin complex has been recognized for several decades, specifically the combination of Thiamine, Pyridoxine and Cyanocobalamin (TPC). Likewise, there is accumulated evidence that indicates an adjuvant analgesic action in low back pain. The aim of the present review is to present the existing evidence and the latest findings on the therapeutic effects of the TPC combination in low back pain. Likewise, some of the most relevant mechanisms of action involved that can explain these effects are analyzed. The reviewed evidence indicates that the combined use of PCT has an adjuvant analgesic effect in mixed pain, specifically in low back pain and other musculoskeletal disorders with nociceptive and neuropathic components. This effect can be explained by an anti-inflammatory, antinociceptive, neuroprotective and neuromodulatory action of the TPC combination on the descending pain system.

Methotrexate-related central neurotoxicity: clinical characteristics, risk factors and genome-wide association study in children treated for acute lymphoblastic leukemia

Symptomatic methotrexate-related central neurotoxicity, 'MTX neurotoxicity', is a severe toxicity experienced during acute lymphoblastic leukemia (ALL) therapy with potential long-term neurologic complications. Risk factors and long-term outcomes require further study. We conducted a systematic, retrospective review of 1251 consecutive Australian children enrolled on BFM or COG-based protocols between 1998-2013. Clinical risk predictors for MTX neurotoxicity were analyzed using regression. A genome-wide association study (GWAS) was performed on 48 cases and 537 controls. The incidence of MTX neurotoxicity was 7.6% (n=95/1251), at a median of 4 months from ALL diagnosis and 8 days after intravenous or intrathecal MTX. Grade 3 elevation of serum aspartate aminotransferase (P=0.005, OR 2.31 (1.28-4.16)) in induction/consolidation was associated with MTX neurotoxicity, after accounting for the only established risk factor, age a10 years. Cumulative incidence of CNS relapse was increased in children where intrathecal MTX was omitted following symptomatic MTX neurotoxicity (n=48) compared to where intrathecal MTX was continued throughout therapy (n=1174) (P=0.047). Five-year CNS relapsefree survival was 89.2%±4.6% when intrathecal MTX was ceased compared to 95.4%±0.6% when intrathecal MTX was continued. Recurrence of MTX neurotoxicity was low (12.9%) for patients whose intrathecal MTX was continued after their first episode. The GWAS identified SNPs associated with MTX neurotoxicity near genes regulating neuronal growth, neuronal differentiation and cytoskeletal organization (P>1E-06). In conclusion, increased serum aspartate aminotransferase and age a10 years at diagnosis were independent risk factors for MTX neurotoxicity. Our data do not support cessation of intrathecal MTX after a first MTX neurotoxicity event.

A Guidance for Concomitant Drug Reconciliation Prior to Allogeneic Hematopoietic Cell Transplantation in Children and Young Adults

Pediatric diseases treated by allogeneic hematopoietic stem cell transplantation (alloHCT) are complex and associated with significant comorbidities and medication requirements that can complicate the transplant process. It is critical to reconcile pre-transplant concomitant medications (pcon-meds) in the weeks prior to alloHCT and to consider the potential for pcon-meds to cause harmful drug-drug interactions (DDIs) or overlapping toxicities with conditioning agents. In this perspective, we describe a systematic process to review pcon-meds and determine the drug modifications needed to avoid DDIs with conditioning regimens. We provide an extensive appendix with timelines for discontinuation or modification of common pcon-meds that patients are taking when presenting to the HCT medical team. The timelines are based on the pharmacokinetic (PK) properties of both the pcon-meds and the planned conditioning medications, as well as anticipated DDIs. They also account for the ages seen at pediatric transplant centers (0-30 years old). Common scenarios, such as when pcon-med discontinuation is not an option, are discussed. Since alloHCT patients are often dependent upon psychiatric medications with problematic DDIs, a table of alternative, non-interacting psychiatric medications is also presented. The appendix provides details regarding how to adjust pcon-meds prior to the start of chemotherapy for children and young adults undergoing alloHCT, however patient-specific circumstances always need to be taken into account. Careful attentiveness to pcon-meds at the time the decision is made to pursue transplant will result in more consistent HCT outcomes, with lower toxicity and increased efficacy of conditioning agents.

Theoretical determination of two-photon absorption in biologically relevant pterin derivatives

Given the prevalence of fluorescence spectroscopy in biological systems, and the prevalence of pterin derivatives throughout biological systems, presented here is an assessment of the two-photon absorption spectroscopy as it applies to a range of the most commonly studied pterin derivatives. QR-CAMB3LYP//ccpVTZ calculations suggest that the use of two-photon spectroscopic methods would enable a more capable differentiation between closely related derivatives in comparison to the one-photon spectra, which show minimal qualitative deviation. Study of short tail derivatives shows that, in most cases, two-photon accessible states solely involve the π* LUMO as the particle orbital, with biopterin, neopterin, and 6-(hydroxymethyl)pterin presenting exceptional potential for targetting. Investigation of derivatives in which the tail contains an aromatic ring resulted in the observation of a series of two-photon accessible states involving charge transfer from the tail to the pterin moiety, the cross sections of which are highly dependent on the adoption of a planar geometry. The observation of these states presents a novel method for tracking the substitution of biologically important molecules such as folic acid and 5-methenyltetrahydrofolylpolyglutamate.

Adverse effects with intravenous methotrexate in children with acute lymphoblastic leukemia/lymphoma: a retrospective study

Methotrexate (MTX) forms the backbone of maintenance cycles in childhood acute lymphoblastic leukemia (ALL) chemotherapy, including interim maintenance. There is sufficient published data describing toxicities of high dose MTX (HD-MTX), but toxicities with escalating doses of MTX (Capizzi regimen) is not well documented. Capizzi regimen is thought to be relatively safe; we contend that even low escalating doses of MTX have significant toxicities. Our study intends to characterise such events with Capizzi MTX in comparison to that seen with HD-MTX. The retrospective study was conducted at a tertiary care centre of North India. We looked for the presence of six main toxicities: febrile neutropenia, thrombocytopenia, mucositis, hepatic toxicity, renal toxicity and skin toxicity from the clinical records of children with newly diagnosed acute lymphoblastic leukemia and lymphoma (intermediate and high risk disease), treated at our centre from November 2013 to July 2018. Intermediate risk ALL (IR-ALL) received Capizzi MTX, whereas high risk ALL (HR-ALL/T-NHL), received HD-MTX. Both these regimens do not use L-asparaginase. A total of 237 cycles of Capizzi escalating MTX and 151 cycles of HD-MTX (B cell: 3 gm/m² and T cell ALL/T-NHL: 5 gm/m²) during interim maintenance were studied in 93 children. Fifty-four (54) children were of IR (all B cell ALL) and 39 of HR-ALL (21 B-ALL, 18 T-ALL/T-NHL). The combined incidence of toxicities, were similar between the two groups: 68/237 cycles (28.7%) of Capizzi MTX and 45/151 cycles (29.8%) of HD-MTX (P = 0.815). However, mucositis was more commonly witnessed in the later group at 22/151 cycle (14.6%) versus 13/237 cycles (5.5%) in Capizzi MTX (P = 0.002). Nephrotoxicity and skin toxicity was seen only in the HD-MTX group. There was no difference in the severity of toxicity, graded using NCI CTCAE v 5.0, between the two groups. There was no mortality directly attributable to methotrexate toxicity (Grade V toxicity). Serum MTX levels were available in 69/151 (45.7%) cycles of HD-MTX and showed no association with toxicity in this group. Also, there was no difference in the incidence of combined toxicities between groups with (19/69 cycles) or without (26/82 cycles) available serum MTX levels in the HR group (P = 0.577). Male gender, lower baseline ANC and lower BMI had significant association with toxicity. Methotrexate related toxicity is common with both Capizzi and HD-MTX schedule in childhood ALL with a correlation of lower BMI, baseline ANC and male gender. However, it is possible to administer Capizzi as well as HD-MTX in lower middle income countries, with manageable toxicity. Further studies will be required to substantiate our findings and determine the predictors of such events.

Should nitrous oxide ever be used in oncology patients receiving methotrexate therapy?

Nitrous oxide (N₂ O) is frequently used for short anesthesia/analgesia in children undergoing painful or repetitive procedures. Children with acute lymphoblastic leukemia (ALL) require repeated lumbar punctures with direct instillation of intrathecal chemotherapy, usually the anti-folate agent methotrexate, during their treatment. These procedures are frequently performed under anesthesia. Concerns have been intermittently raised about a drug interaction between methotrexate and N₂ O that may potentiate the undesirable side effects of methotrexate, including neurotoxicity. However, the clinical evidence consists mainly of isolated case reports leading to a lack of consensus among pediatric anesthetists about the relative risk benefits of using N₂ O in children with ALL. In this article, we review the biochemical basis and scientific observations that suggest a significant interaction between N₂ O and methotrexate due to their dual inhibition of the key enzyme methionine synthase. The possible role of this interaction in potentiating neurotoxicity in children with cancer is discussed, and arguments and counterarguments about the clinical significance of this largely theoretical relationship are explored. Following comprehensive review of all the available data, we make the case for the circumstantial evidence being sufficiently compelling to prompt a review of practice by pediatric anesthetists and call for a precautionary approach by avoiding the use of N₂ O in children receiving concurrent methotrexate.

The Use of Ommaya Reservoirs to Deliver Central Nervous System-Directed Chemotherapy in Childhood Acute Lymphoblastic Leukaemia

Prophylactic eradication of central nervous system (CNS) leukaemia is the current standard of care in treating childhood acute lymphoblastic leukaemia (ALL). This is conventionally achieved through regular lumbar punctures with intrathecal injections of methotrexate into the cerebrospinal fluid (CSF). Ommaya reservoirs are subcutaneous implantable devices that provide a secure route of drug delivery into the CSF via an intraventricular catheter. They are an important alternative in cases where intrathecal injection via lumbar puncture is difficult. Among UK Paediatric Principal Treatment Centres for ALL we found considerable variation in methotrexate dosing when using an Ommaya reservoir. We review the current safety and theoretical considerations when using Ommaya reservoirs and evidence for methotrexate dose adjustments via this route. We conclude by summarising the pragmatic consensus decision to use 50% of the conventional intrathecal dose of methotrexate when it is administered via Ommaya reservoir in front-line ALL therapy.

Effect of methotrexate/vitamin B12 on DNA methylation as a potential factor in leukemia treatment-related neurotoxicity

Methotrexate (MTX) is administered to treat childhood acute lymphoblastic leukemia (ALL). It acts by inhibiting dihydrofolate reductase which reduces methyltetrahydrofolate, a key component in one carbon metabolism, thus reducing cell proliferation. Further perturbations to one carbon metabolism, such as reduced vitamin B₁₂ levels via the use of nitrous oxide for sedation during childhood ALL treatment, may increase neurotoxicity risk. With B₁₂ as an enzymatic cofactor, methyltetrahydrofolate is essential to produce methionine, which is critical for DNA methylation. We investigated global and gene specific DNA methylation in neuronal cell lines in response to MTX treatment and vitamin B₁₂ concentration individually, and in combination. Results: MTX treatment alone significantly increased LINE-1 methylation in SH-SY5Y (p = 0.040) and DAOY (p < 0.001), and increased FKBP5 methylation in MO3.13 cells (p = 0.009). Conclusion: We conclude that altered DNA methylation of brain/central nervous system cells could be one mechanism involved in MTX treatment-related neurotoxicities and neurocognitive late effects in ALL survivors.

Neurotoxicity after high-dose methotrexate (MTX) is adequately explained by insufficient folinic acid rescue

PURPOSE

To challenge the view that the dose of folinic acid rescue after high-dose methotrexate (MTX) has no significance in the prevention of neurotoxicity and to present the minority view that neurotoxicity can be prevented by an adequate dose of folinic acid, without compromising treatment results. Several fallacies that led to the misunderstanding of post MTX neurotoxicity are presented.

METHODS

Data mining using search engines was used to find relevant publications, and an e-mail survey of more than 60 authors of articles in this field was performed. All relevant articles identified were read in their entirety.

RESULTS

Examples of clinical studies with neurotoxicity following inadequate rescue are given. Some studies demonstrated no neurotoxicity when adequate doses of folinic acid rescue were started 24-36 h after the start of HDMTX rescue even after mega doses of MTX. Rescue started after 42 h was associated with neurotoxicity except in patients with low serum MTX levels after 24 and 36 h. ALL protocols with neurotoxicity, especially BFM-like protocols, are presented. Protocol is reported in which single protocol changes prevented neurotoxicity.

CONCLUSIONS

From the published data, when folinic acid rescue is given in a sufficiently high enough dose and is started 24-36 h after the beginning of the methotrexate exposure, and virtually all forms of post MTX neurotoxicity can be prevented without compromising therapeutic results.

Non-infectious chemotherapy-associated acute toxicities during childhood acute lymphoblastic leukemia therapy

During chemotherapy for childhood acute lymphoblastic leukemia, all organs can be affected by severe acute side effects, the most common being opportunistic infections, mucositis, central or peripheral neuropathy (or both), bone toxicities (including osteonecrosis), thromboembolism, sinusoidal obstruction syndrome, endocrinopathies (especially steroid-induced adrenal insufficiency and hyperglycemia), high-dose methotrexate-induced nephrotoxicity, asparaginase-associated hypersensitivity, pancreatitis, and hyperlipidemia. Few of the non-infectious acute toxicities are associated with clinically useful risk factors, and across study groups there has been wide diversity in toxicity definitions, capture strategies, and reporting, thus hampering meaningful comparisons of toxicity incidences for different leukemia protocols. Since treatment of acute lymphoblastic leukemia now yields 5-year overall survival rates above 90%, there is a need for strategies for assessing the burden of toxicities in the overall evaluation of anti-leukemic therapy programs.