Risk analysis of severe myelotoxicity with temozolomide: the effects of clinical and genetic factors

Development of a robust predictive model for neutropenia after esophageal cancer chemotherapy using GLMMLasso

BACKGROUND

Neutropenia can easily progress to febrile neutropenia and is a risk factor for life-threatening infections. Predicting and preventing severe neutropenia can help avoid such infections.

AIM

This study aimed to develop an optimal model using advanced statistical methods to predict neutropenia after 5-fluorouracil/cisplatin chemotherapy for esophageal cancer and to create a nomogram for clinical application.

METHOD

Patients who received 5-fluorouracil/cisplatin chemotherapy at Chiba University Hospital, Japan, between January 2011 and March 2021 were included. Clinical parameters were measured before the first, second, and third chemotherapy cycles and were randomly divided by patient into a training cohort (60%) and test cohort (40%). The predictive performance of Logistic, Stepwise, Lasso, and GLMMLasso models was evaluated by the area under the receiver-operating characteristic curve (AUC). A nomogram based on GLMMLasso was developed, and the accuracy of probabilistic predictions was evaluated by the Brier score.

RESULTS

The AUC for the first cycle of chemotherapy was 0.781 for GLMMLasso, 0.751 for Lasso, 0.697 for Stepwise, and 0.669 for Logistic. The respective AUCs for GLMMLasso in the second and third cycles were 0.704 and 0.900. The variables selected by GLMMLasso were cisplatin dose, 5-fluorouracil dose, use of leucovorin, sex, cholinesterase, and platelets. A nomogram predicting neutropenia was created based on each regression coefficient. The Brier score for the nomogram was 0.139.

CONCLUSION

We have developed a predictive model with high performance using GLMMLasso. Our nomogram can represent risk visually and may facilitate the assessment of the probability of chemotherapy-induced severe neutropenia in clinical practice.

Functional germline variants in DNA damage repair pathways are associated with altered survival in adults with glioma treated with temozolomide

Background

Temozolomide (TMZ) treatment has demonstrated, but variable, impact on glioma prognosis. This study examines associations of survival with DNA repair gene germline polymorphisms among glioma patients who did and did not have TMZ treatment. Identifying genetic markers which sensitize tumor cells to TMZ could personalize therapy and improve outcomes.

Methods

We evaluated TMZ-related survival associations of pathogenic germline SNPs and genetically predicted transcript levels within 34 DNA repair genes among 1504 glioma patients from the UCSF Adult Glioma Study and Mayo Clinic whose diagnoses spanned pre- and post-TMZ eras within the major known glioma prognostic molecular subtypes.

Results

Among those who received TMZ, 5 SNPs were associated with overall survival, but not in those who did not receive TMZ. Only rs2308321-G, in MGMT, was associated with decreased survival (HR=1.21, p=0.019) for all glioma subtypes. Rs73191162-T (near UNG), rs13076508-C (near PARP3), rs7840433-A (near NEIL2), and rs3130618-A (near MSH5) were only associated with survival and TMZ treatment for certain subtypes, suggesting subtype-specific germline chemo-sensitization.Genetically predicted elevated compared to normal brain expression of PNKP was associated with dramatically worse survival for TMZ-treated patients with IDH-mutant and 1p/19q non-codeleted gliomas (p=0.015). Similarly, NEIL2 and TDG expressions were associated with altered TMZ-related survival only among certain subtypes.

Conclusions

Functional germline alterations within DNA repair genes were associated with TMZ sensitivity, measured by overall survival, among adults with glioma, these variants should be evaluated in prospective analyses and functional studies.

Comprehensive understanding of the adverse effects associated with temozolomide: a disproportionate analysis based on the FAERS database

Background

Temozolomide, which is the standard drug for glioma treatment, has several Adverse events (AEs) in the treatment of gliomas and other tumors that are not yet fully understood. This is due to the pharmacological nature of the alkylating agent. A significant proportion of these effects have not been systematically documented or reported.

Methods

We selected data from the United States FDA Adverse Event Reporting System (FAERS) database from the first quarter of 2004 to the fourth quarter of 2023. Four algorithms were used for disproportionate analysis, with the objective of assessing the association between temozolomide and related adverse events.

Results

In this study, 20,079,906 case reports were collected from the FAERS database, of which 15,152 adverse events related to temozolomide were reported. A total of 352 preferred terms (PTs) and 24 system organ classes (SOCs) that were significantly disproportionally related to the four algorithms were included. The SOCs included blood and lymphatic system disorders (χ2 = 18,220.09, n = 4,325); skin and subcutaneous tissue disorders (χ2 = 408.06, n = 1,347); investigations (χ2 = 639.44, n = 3,925); musculoskeletal and connective tissue disorders (χ2 = 1,317.29, n = 588); and psychiatric disorders (χ2 = 1,098.47, n = 877). PT levels were screened for adverse drug reaction signals consistent with drug inserts, such as anemia, thrombocytopenia, liver function abnormalities, nausea and vomiting, as well as rarely reported adverse drug reactions, such as aplastic anemia, myelodysplastic syndromes, electrolyte disorders, cerebral edema, and high-frequency mutations.

Conclusion

The results of our investigation demonstrated both adverse effects that had been reported and a multitude of unreported adverse effects that were serious in nature and lacked a clear cause. These novel findings suggest that more attention should be given to the clinical conditions of patients after treatment to provide a more comprehensive perspective and understanding for further clarifying the safety of temozolomide.

Early Identification of Patients at Risk of Cabazitaxel-induced Severe Neutropenia

BACKGROUND

Cabazitaxel frequently causes severe neutropenia. A higher cabazitaxel systemic exposure is related to a lower nadir absolute neutrophil count (ANC).

OBJECTIVE

To describe the effect of cabazitaxel systemic exposure on ANC by a population pharmacokinetic/pharmacodynamic (POP-PK/PD) model, and to identify patients at risk of severe neutropenia early in their treatment course using a PK threshold.

DESIGN, SETTING, AND PARTICIPANTS

Data from five clinical studies were pooled to develop a POP-PK/PD model using NONMEM, linking both patient characteristics and cabazitaxel systemic exposure directly to ANC.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

A PK threshold, predictive of severe neutropenia (grade ≥3), was determined using a receiver operating characteristic curve.

RESULTS AND LIMITATIONS

Ninety-six patients were included with a total of 1726 PK samples and 1081 ANCs. The POP-PK/PD model described both cabazitaxel PK and ANC accurately. A cabazitaxel plasma concentration of >4.96 ng/ml at 6 h after the start of infusion was found to be predictive of severe neutropenia, with a sensitivity of 76% and a specificity of 65%.

CONCLUSIONS

Early cabazitaxel plasma levels are predictive of severe neutropenia. Implementation of the proposed PK threshold results in early identification of almost 76% of all severe neutropenias. If prospectively validated, patients at risk could benefit from prophylactic administration of granulocyte colony stimulating factors, preventing severe neutropenia in an early phase of treatment. Implementation of this threshold permits a less restricted use of the 25 mg/m2 dose, potentially increasing the therapeutic benefit.

PATIENT SUMMARY

Treatment with cabazitaxel chemotherapy often causes neutropenia, leading to susceptibility to infections, which might be life threatening. We found that a systemic cabazitaxel concentration above 4.96 ng/ml 6 h after the start of infusion is predictive of the occurrence of severe neutropenia. Measurement of systemic cabazitaxel levels provides clinicians with the opportunity to prophylactically stimulate neutrophil growth.

Prognosis of MGMT -Positive Gene in Patients with Brain Tumors of Grade III and Grade IV

Sumit GoyalObjective  To evaluate MGMT gene positivity is associated with better survival in patients diagnosed with brain tumor World Health Organization (WHO) grades III and IV Material and Methods  Single-institute restrospective study. A total of 80 patients were enrolled, all underwent surgery either total or subtotal excision of the tumor and MGMT gene testing on tumor tissue by RT-PCR. All received adjuvant radiation (60 Gy/30 fractions, 5 fractions/week) with concurrent temozolomide (75 mg/m 2 ), followed by 12 cycles of adjuvant temozolomide (150 mg/m 2 1st cycle followed by 200 mg/m 2 ) with regular follow-up. Results  A total of 80 patients, 75 underwent subtotal excision, 27 were WHO grade III vs. 48 WHO grade IV. Five underwent total excision 1 was WHO grade III vs. 4 WHO grade IV. The median PFS and OS in five patients in total excision in grade III patient was 9.0 and 20 compared with Grade IV, where the median PFS and OS was 8.8 and 17.8 months. Out of 75 patients in the subtotal group median PFS and OS, respectively, in Grade III group was 9.1 and 19.3 and, WHO grade IV with median PFS of 8.8 and OS of 18.8. Conclusion   MGMT gene positivity is a prognostic factor in grade III and IV brain tumor.

Effect of Pneumocystis jirovecii pneumonia prophylaxis on hematologic toxicity in patients receiving chemoradiation for primary brain tumors

PURPOSE

Diffuse gliomas are managed with radiation and temozolomide; however, this therapy often results in hematologic toxicities. Patients undergoing chemoradiation also risk contracting Pneumocystis jirovecii pneumonia (PJP), and frequently receive prophylaxis against PJP during treatment. Independent of chemoradiation, some PJP prophylaxis drugs have the potential to cause myelosuppression, which could require cessation of chemotherapy. Here, we evaluate differences in the frequency of hematologic toxicities during chemoradiation when patients receive PJP prophylaxis.

METHODS

This retrospective chart review evaluated patients with primary brain tumors treated with radiation and concurrent temozolomide. Analyses were performed to assess the effect of the type of PJP prophylaxis on risk for neutropenia, lymphopenia, or thrombocytopenia and the severity of these adverse effects as defined using the Common Terminology Criteria for Adverse Events.

RESULTS

Of the 217 patients included in this analysis, 144 received trimethoprim-sulfamethoxazole (TMP/SMX) and 69 received pentamidine. Of the patients who received TMP/SMX, 15.3% developed an absolute neutrophil count < 1500 cells/µL compared with 7.2% of patients receiving pentamidine (p = 0.10). Platelet count < 100,000/µL occurred in 18.1% of patients who received TMP/SMX and 20.3% of patients who received pentamidine (p = 0.70). No significant differences in lymphocyte counts between therapies were seen. Severity of hematologic toxicities were similar between PJP prophylaxis groups.

CONCLUSION

These findings suggest that the type of PJP prophylaxis does not significantly affect the risk for hematologic toxicity in brain tumor patients receiving radiation and temozolomide. Additional studies are merited to evaluate the higher rate of neutropenia in patients on TMP/SMX observed in this study.

Myelotoxicity of Temozolomide Treatment in Patients with Glioblastoma Is It Time for a More Mechanistic Approach?

Glioblastoma multiforme is the most common primary central nervous system tumor, with an incidence of 3 [...].

Patterns, predictors and prognostic relevance of high-grade hematotoxicity after temozolomide or temozolomide-lomustine in the CeTeG/NOA-09 trial

PURPOSE

In the randomized phase III trial CeTeG/NOA-09, temozolomide (TMZ)/lomustine (CCNU) combination therapy was superior to TMZ in newly diagnosed MGMT methylated glioblastoma, albeit reporting more frequent hematotoxicity. Here, we analyze high grade hematotoxicity and its prognostic relevance in the trial population.

METHODS

Descriptive and comparative analysis of hematotoxicity adverse events ≥ grade 3 (HAE) according to the Common Terminology of Clinical Adverse Events, version 4.0 was performed. The association of HAE with survival was assessed in a landmark analysis. Logistic regression analysis was performed to predict HAE during the concomitant phase of chemotherapy.

RESULTS

HAE occurred in 36.4% and 28.6% of patients under CCNU/TMZ and TMZ treatment, respectively. The median onset of the first HAE was during concomitant chemotherapy (i.e. first CCNU/TMZ course or daily TMZ therapy), and 42.9% of patients with HAE receiving further courses experienced repeat HAE. Median HAE duration was similar between treatment arms (CCNU/TMZ 11.5; TMZ 13 days). Chemotherapy was more often discontinued due to HAE in CCNU/TMZ than in TMZ (19.7 vs. 6.3%, p = 0.036). The occurrence of HAE was not associated with survival differences (p = 0.76). Regression analysis confirmed older age (OR 1.08) and female sex (OR 2.47), but not treatment arm, as predictors of HAE.

CONCLUSION

Older age and female sex are associated with higher incidence of HAE. Although occurrence of HAE was not associated with shorter survival, reliable prediction of patients at risk might be beneficial to allow optimal management of therapy and allocation of supportive measures.

TRIAL REGISTRATION

NCT01149109.

Prognostic significance of therapy-induced myelosuppression in newly diagnosed glioblastoma

BACKGROUND

Myelosuppression is the major toxicity encountered during temozolomide chemoradiotherapy for newly diagnosed glioblastoma.

METHODS

We assessed the association of myelosuppression (neutropenia, thrombocytopenia, anemia, and lymphopenia) during temozolomide chemoradiotherapy alone or in combination with experimental agents with progression-free survival (PFS) or overall survival (OS) in 2073 patients with newly diagnosed glioblastoma enrolled into five clinical trials: CENTRIC, CORE, EORTC 26082, AVAglio, and EORTC 26981. A landmark Cox model was used. For each primary association analysis, a significance level of 1.7% was used.

RESULTS

Lower neutrophil counts at baseline were associated with better PFS (P = .011) and OS (P < .001), independently of steroid intake. Females experienced uniformly more myelotoxicity than males. Lymphopenia during concomitant chemoradiotherapy was associated with OS (P = .009): low-grade (1-2) lymphopenia might be associated with superior OS (HR 0.78, 98.3% CI 0.58-1.06), whereas high-grade (3-4) lymphopenia might be associated with inferior OS (HR 1.08, 98.3% CI 0.75-1.54). There were no associations of altered hematological parameters during concomitant chemoradiotherapy with PFS. During maintenance chemoradiotherapy, no significant association was found between any parameter of myelosuppression and PFS or OS, although exploratory analysis at 5% significance level indicated that either mild-to-moderate (HR 0.76, 95% CI 0.62-0.93) or high-grade lymphopenia (HR 0.65, 95% CI 0.46-0.92) was associated with superior OS (P = .013), but not PFS.

CONCLUSIONS

The association of higher neutrophil counts at baseline with inferior PFS and OS requires further prospective evaluation. The link of therapy-induced lymphopenia to better outcome may guide the design for immunotherapy trials in newly diagnosed glioblastoma.

Temozolomide: an Overview of Biological Properties, Drug Delivery Nanosystems, and Analytical Methods

Temozolomide (TMZ) is an imidazotetrazine prodrug used to treat glioblastoma multiforme. Its physicochemical prop-erties and small size confer the ability to cross the blood-brain barrier. The antitumor activity depends on pH-dependent hydrolysis of the methyldiazonium cation, which is capable of methylating purine bases (O6-guanine; N7-guanine, and N3-adenine) and causing DNA damage and cell death. TMZ is more stable in acidic media (pH ≤ 5.0) than in basic media (pH ≥ 7.0) due to the protonated form that minimizes the catalytic process. Because of this, TMZ has high oral bioavailability, but it has a half-life of 1.8 h and low brain distribution (17.8%), requiring a repeated dos-ing regimen that limits its efficacy and increases adverse events. Drug delivery Nanosystems (DDNs) improve the phys-icochemical properties of TMZ and may provide controlled and targeted delivery. Therefore, DDNs can increase the efficacy and safety of TMZ. In this context, to ensure the efficiency of DDNs, analytical methods are used to evaluate TMZ pharmacokinetic parameters, encapsulation efficiency, and the release profile of DDNs. Among the methods, high-performance liquid chromatography is the most used due to its detection sensitivity in complex matrices such as tissues and plasma. Micellar electrokinetic chromatography features fast analysis and no sample pretreatment. Spec-trophotometric methods are still used to determine encapsulation efficiency due to their low cost, despite their low sen-sitivity. This review summarizes the physicochemical and pharmacological properties of free TMZ and TMZ-loaded DDNs. In addition, this review addresses the main analytical methods employed to characterize TMZ in different ma-trices.

Temozolomide-induced myelotoxicity and single nucleotide polymorphisms in the MGMT gene in patients with adult diffuse glioma: a single-institutional pharmacogenetic study

PURPOSE

Nearly 10% of patients with adult diffuse glioma develop clinically significant myelotoxicity while on temozolomide (TMZ) leading to treatment interruptions. This study aimed to assess single nucleotide polymorphisms (SNPs) in the O⁶-methylguanine-DNA methyltransferase (MGMT) gene in adults with biopsy-proven diffuse glioma who develop TMZ-induced myelotoxicity and correlate their presence with severity and duration of such toxicity.

METHODS

This study assessed 33 adults treated with TMZ for diffuse glioma who developed ≥ grade 2 thrombocytopenia and/or ≥ grade 3 neutropenia. Genomic DNA was extracted from peripheral blood cells for MGMT SNP analysis after written informed consent. TMZ-induced severe myelotoxicity (≥ grade 3) was correlated with three specified SNPs commonly seen in the MGMT gene (L84F, I143V/K178R) using chi-square test or Fischer's exact test as appropriate.

RESULTS

Of the 33 adults, 24 (72.7%) experienced ≥ grade 3 thrombocytopenia and/or neutropenia, while 9 (27.3%) developed grade 2 thrombocytopenia only. The variant T allele of L84F was expressed in 28.7% (19/66) of analyzed alleles, which was substantially higher than previously reported for South Asian ancestry. The variant G allele of I143V/K178R was expressed in 9.3% (6/64) of analyzed alleles. Of which 3 patients showed statistically significant association with prolonged myelosuppression for > 2 months (p = 0.03). No significant correlation was established between the mentioned SNPs and severe myelotoxicity.

CONCLUSIONS

There is substantially higher frequency of variant T allele (L84F) in Indian patients than previously reported for South Asians. The presence of specific SNPs in the MGMT gene correlates with prolonged duration but not severity of TMZ-induced myelotoxicity.

Hematological adverse events in the management of glioblastoma

BACKGROUND

Hematological adverse events (HAEs) are common during treatment for glioblastoma (GBM), usually associated with temozolomide (TMZ). Their clinical value is uncertain, as few investigations have focused on outcomes for HAEs during GBM treatment.

METHODS

We combined data from two randomized clinical trials, RTOG 0525 and RTOG 0825, to analyze HAEs during treatment for GBM. We investigated differences between chemoradiation and adjuvant therapy, and by regimen received during adjuvant treatment.

RESULTS

1454 patients participated in these trials, of which 1154 (79.4%) developed HAEs. During chemoradiation, 44.4% of patients developed HAEs (54% involving more than one cell line), and were most commonly lymphopenia (50.6%), and thrombocytopenia (47.5%). During adjuvant treatment, 45% of patients presented HAEs (78.6% involving more than one cell line), and were more commonly leukopenia (62.7%), and thrombocytopenia (62.3%). Median overall survival (OS) and progression free survival (PFS) were longer in patients with HAEs (OS 19.4 months and PFS 9.9 months) compared to those with other or no adverse events (OS 14.1 months and PFS 5.9 months). There was no significant difference in survival between grade 1 and/or 2 versus grade 3 and/or 4 HAEs. History of HAEs during chemoradiation was a protective factor for presentation of HAEs during adjuvant therapy.

CONCLUSION

HAEs are common during GBM treatment, and often involve more than one cell line (more likely during adjuvant therapy). HAEs may be associated with prolonged OS and PFS, particularly during adjuvant therapy. HAEs during chemoradiation was a protective factor for HAEs during adjuvant therapy.

Germline polymorphisms in MGMT associated with temozolomide-related myelotoxicity risk in patients with glioblastoma treated on NRG Oncology/RTOG 0825

Background

We sought to identify clinical and genetic predictors of temozolomide-related myelotoxicity among patients receiving therapy for glioblastoma.

Methods

Patients (n = 591) receiving therapy on NRG Oncology/RTOG 0825 were included in the analysis. Cases were patients with severe myelotoxicity (grade 3 and higher leukopenia, neutropenia, and/or thrombocytopenia); controls were patients without such toxicity. A risk-prediction model was built and cross-validated by logistic regression using only clinical variables and extended using polymorphisms associated with myelotoxicity.

Results

23% of patients developed myelotoxicity (n = 134). This toxicity was first reported during the concurrent phase of therapy for 56 patients; 30 stopped treatment due to toxicity. Among those who continued therapy (n = 26), 11 experienced myelotoxicity again. The final multivariable clinical factor model included treatment arm, gender, and anticonvulsant status and had low prediction accuracy (area under the curve [AUC] = 0.672). The final extended risk prediction model including four polymorphisms in MGMT had better prediction (AUC = 0.827). Receiving combination chemotherapy (OR, 1.82; 95% CI, 1.02-3.27) and being female (OR, 4.45; 95% CI, 2.45-8.08) significantly increased myelotoxicity risk. For each additional minor allele in the polymorphisms, the risk increased by 64% (OR, 1.64; 95% CI, 1.43-1.89).

Conclusions

Myelotoxicity during concurrent chemoradiation with temozolomide is an uncommon but serious event, often leading to treatment cessation. Successful prediction of toxicity may lead to more cost-effective individualized monitoring of at-risk subjects. The addition of genetic factors greatly enhanced our ability to predict toxicity among a group of similarly treated glioblastoma patients.

Characterization and Prognosis of Temozolomide-Induced Aplastic Anemia in Patients with Central Nervous System Malignancies

BACKGROUND

Temozolomide-induced aplastic anemia (TIAA) is a rare but highly challenging complication of temozolomide (TMZ) therapy. Evidence describing prognosis, clinical characteristics, and treatment of this entity is very limited.

METHODS

We performed a multicenter, 22-year observational cohort study of patients with central nervous system (CNS) malignancies treated with temozolomide who developed TIAA, retrospectively analyzing prognosis, complications, and recovery. TIAA was defined using adapted evidence-based severe aplastic anemia criteria incorporating profound cytopenias and a minimum duration (4 weeks) without hematologic recovery.

RESULTS

Of 3,821 patients with CNS malignancies receiving TMZ, 34 patients (0.89%) met criteria for TIAA. Onset was rapid, with 29 patients (85.3%) developing TIAA before completing a second TMZ cycle. 23 patients (67.6%) ultimately achieved a hematologic recovery. Patients without recovery were more likely to develop febrile neutropenia (72.7% vs. 30.4%, P=0.03), infectious complications (45.5% vs. 8.7%, P=0.02), require hospitalization (81.8% vs. 43.5%, P=0.04), and die (100.0% vs. 60.9%, P=0.02). Median overall survival from TIAA diagnosis was 752 days in patients achieving a partial hematologic recovery versus 28 days in those who did not (P<0.0001). 29 patients (85.3%) received one or more hematopoietic growth factors; hematologic recovery rates were higher in patients receiving thrombopoietin receptor agonists (81.8% vs. 60.9%) but were not higher in patients receiving granulocyte colony stimulating factors.

CONCLUSIONS

TIAA occurs in <1% of patients receiving TMZ for CNS malignancies, but is highly morbid when it occurs and frequently fatal in the one-third of patients not achieving hematologic recovery. Thrombopoietin receptor agonists may improve the likelihood of a hematologic recovery.

Toxicities and Associated Factors in Patients Receiving Temozolomide-Containing Regimens: A 12-Year Analysis of Hospital Data

OBJECTIVE

Although temozolomide has been extensively used to treat various tumors, there is a lack of large-cohort studies on temozolomide's toxicity profile. The toxicity profiles and associated factors in patients treated with temozolomide-containing regimens were analyzed.

PATIENTS AND METHODS

Patients treated with temozolomide-containing regimens in the Affiliated Union Hospital of Huazhong University of Science and Technology from January 2008 to December 2019 were included. A retrospective analysis of the clinical data of patients treated with temozolomide-containing regimens was performed. Univariate chi-square test and multivariate logistic regression analysis were employed to identify factors associated with the occurrence of toxicities.

RESULTS

Among the 1057 patients received temozolomide-containing regimens, 922 patients were included in our analyses. Of the 922 patients, 484 patients (52.5%) experienced toxicities. Univariate analysis revealed that radiotherapy, chemotherapy cycle, chemotherapy regimen, and clinical stage were significantly associated with the toxicity during temozolomide treatment (P < 0.05). The chemotherapy regimen, chemotherapy cycle, and clinical stage were significantly associated with the overall occurrence of toxicities (P < 0.05). A chemotherapy regimen, chemotherapy cycle, and clinical stage were associated with the hematological system's toxicities, whereas gender, age, clinical diagnosis, and clinical stage were related to gastrointestinal toxicities (P < 0.05). Clinical diagnosis, chemotherapy regimen, and age were associated with liver toxicity (P < 0.05).

CONCLUSION

Toxicities are common among patients receiving temozolomide-containing regimens. Clinicians should be aware of factors associated with toxicities to minimize the impact of the toxicity.

Design, synthesis and in vivo anticancer activity of novel parthenolide and micheliolide derivatives as NF-κB and STAT3 inhibitors

Parthenolide and micheliolide have attracted great attention in anticancer research due to their unique activities. In this study, thirteen parthenolide derivatives and twenty-three micheliolide derivatives were synthesized. Most synthesized compounds showed higher cytotoxicity than parthenolide or micheliolide. The in vivo anticancer activity of several representative compounds was evaluated in mice. One micheliolide derivative, 9-oxomicheliolide (43), showed promising in vivo antitumor activity compared with clinical drugs cyclophosphamide or temozolomide. Compound 43 was particularly effective against glioblastoma, with its tumor inhibition rate in mice comparable to the drug temozolomide. The discovery of compound 43 also demonstrates the feasibility of developing anticancer micheliolide derivatives by modification at C-9 position. Anticancer mechanism studies revealed that 9-oxomicheliolide exhibited inhibition effect against NF-κB and STAT3 signaling pathways, as well as induction effects of cell apoptosis. It is postulated that 9-oxomicheliolide is likely to be a modulator of the immune system, which regulates the anticancer immune responses.

Epilepsy Risk Prediction Model for Patients With Tuberous Sclerosis Complex

BACKGROUND

Individuals with tuberous sclerosis complex are at increased risk of epilepsy. Early seizure control improves developmental outcomes, making identifying at-risk patients critically important. Despite several identified risk factors, it remains difficult to predict. The purpose of the study was to evaluate the combined risk prediction of previously identified risk factors for epilepsy in individuals with tuberous sclerosis complex.

METHODS

The study group (n = 333) consisted of individuals with tuberous sclerosis complex who were enrolled in the Tuberous Sclerosis Complex Autism Center of Excellence Research Network and UT TSC Biobank. The outcome was defined as having an epilepsy diagnosis. Potential risk factors included sex, TSC genotype, and tuber presence. Logistic regression was used to calculate the odds ratio and P value for the association between each variable and epilepsy. A clinical risk prediction model incorporating all risk factors was built. Area under the curve was calculated to characterize the full model's ability to discriminate individuals with tuberous sclerosis complex with and without epilepsy.

RESULTS

The strongest risk for epilepsy was presence of tubers (95% confidence interval: 2.39 to 10.89). Individuals with pathogenic TSC2 variants were three times more likely (95% confidence interval: 1.55 to 6.36) to develop seizures compared with those with tuberous sclerosis complex from other causes. The combination of risk factors resulted in an area under the curve 0.73.

CONCLUSIONS

Simple characteristics of patients with tuberous sclerosis complex can be combined to successfully predict epilepsy risk. A risk assessment model that incorporates sex, TSC genotype, protective TSC2 missense variant, and tuber presence correctly predicts epilepsy in 73% of patients with tuberous sclerosis complex.

Development of Aplastic Anemia during Treatment of Anaplastic Astrocytoma with Temozolomide

Temozolomide (TMZ) is an oral alkylating agent that is considered the standard therapy in primary intracranial malignancies. The medication is well tolerated with a most common side effect of bone marrow suppression that is encountered in a small proportion of patients, often reversible with medication discontinuation and supportive treatment. Rarely, aplastic anemia can develop during treatment with TMZ. Here, we present a case of a patient who developed aplastic anemia following treatment with TMZ. We offer a review of the existing literature to have a better understanding of the causative effect and to examine the characteristics and outcomes when aplastic anemia develops during treatment with TMZ.

Sex-specific aspects of epidemiology, molecular genetics and outcome: primary brain tumours

Recent years have seen a great interest in sex-specific aspects of many diseases, including cancer, in part because of the assumption that females have often not been adequately represented in early drug development and determination of safety, tolerability and efficacy in clinical trials. Brain tumours represent a highly heterogeneous group of neoplastic diseases with strong variation of incidence by age, but partly also by sex. Most gliomas are more common in men whereas meningiomas, the most common primary intracranial tumours, are more common in females. Potential sex-specific genetic risk factors and specific sex biology have been reported in a tumour-specific manner. Several small studies have indicated differences in tolerability and safety of, as well as benefit from, treatment by sex, but no conclusive data have been generated. Exploring sex-specific aspects of neuro-oncology should be studied more systematically and in more depth in order to uncover the biological reasons for known sex differences in this disease.

Sex-specific and gender-specific aspects in patient-reported outcomes

Patient-reported outcomes (PROs) are important tools in patient-centred medicine and allow for individual assessment of symptom burden and aspects of patients’ quality of life. While sex and gender differences have emerged in preclinical and clinical medicine, these differences are not adequately represented in the development and use of patient-reported outcome measures. However, even in personalised approaches, undesirable biases may occur when samples are unbalanced for certain characteristics, such as sex or gender. This review summarises the current status of the literature and trends in PROs with a focus on sex and gender aspects.

The Prognostic Impact of Nutritional Status on Postoperative Outcomes in Glioblastoma

OBJECTIVE

The clinical impact and optimal method of assessing nutritional status (NS) have not been rigorously examined in glioblastoma. We investigated the relationship between NS and postoperative survival (PS) in glioblastoma using 4 nutritional indices and identified which index best modeled PS.

METHODS

NS was retrospectively assessed for patients with glioblastoma undergoing surgery at our institution from 2007 to 2019 using the albumin level, albumin/globulin ratio (AGR), nutritional risk index (NRI), and prognostic nutritional index (PNI). Optimal cut points for each index were identified using maximally selected rank statistics and previously established criteria. The predictive value of each index on PS was determined using Cox proportional hazards models adjusted for prognostic variables. The best-performing model was identified using the Akaike Information Criterion.

RESULTS

Our analysis included 242 patients (64% male) with a mean age of 57.6 years, Karnofsky Performance Status of 77.6, 5-factor modified frailty index of 0.59, albumin level of 4.2 g/dL, AGR of 1.9, NRI of 105.6, and PNI of 47.4. Median PS after index and repeat surgery was 12.7 and 7.8 months, respectively. On multivariable analysis, low albumin level (hazard ratio [HR], 2.09; 95% confidence interval [CI], 1.52-2.89; P < 0.001), mild NRI (HR, 1.61; 95% CI, 1.04-2.49; P = 0.032), moderate/severe NRI (HR, 2.51; 95% CI, 1.64-3.85; P < 0.001), and low PNI (HR, 2.51; 95% CI, 1.78-3.53; P < 0.001), but not low AGR (HR, 1.17; 95% CI, 0.89-1.54; P = 0.270), predicted decreased PS. PNI had the lowest Akaike Information Criterion.

CONCLUSIONS

NS predicts PS in glioblastoma. PNI may provide the best model for assessing NS. NS is an important modifiable aspect of brain tumor management that warrants increased attention.

Temozolomide-induced aplastic anaemia: Case report and review of the literature

INTRODUCTION

Temozolomide (TMZ) is an oral alkylating agent principally indicated for neurological malignancies including glioblastoma (GBM) and astrocytoma. Most common side effects are mild to moderate, and include fatigue, nausea, vomiting, thrombocytopenia and neutropenia. Severe or prolonged myelosuppression, causing delayed treatment or discontinuation, is uncommon. Major haematological adverse effects such as myelodysplastic syndrome or aplastic anaemia (AA) have rarely been reported.

CASE REPORT

We report a 68-year old female with GBM treated at a tertiary hospital with short-course radiotherapy and concurrent temozolomide following craniotomy. On treatment completion she was transferred to our hospital for rehabilitation. She was thrombocytopenic on admission. Platelets continued falling with significant pancytopenia developing over the next two weeks. Blood parameters and a markedly hypocellular bone marrow confirmed the diagnosis of very severe AA, probably due to TMZ.

MANAGEMENT AND OUTCOME

Treatment consisted of repeated platelet transfusions, intravenous antibiotics, antiviral and antifungal prophylaxis, and G-CSF 300 mcg daily. Platelet and neutrophil counts had returned to normal at 38 days following the completion of TMZ treatment.

DISCUSSION

Whilst most cases of AA are idiopathic, a careful drug, occupational exposure and family history should be obtained, as acquired AA may result from viruses, chemical exposure, radiation and medications. Temozolomide-induced AA is well documented, though only 12 cases have been described in detail. Other potential causes were eliminated in our patient. Physicians should be aware of this rare and potentially fatal toxicity when prescribing. Frequent blood tests should be performed, during and following TMZ treatment, to enable early detection.

Long-lasting Thrombocytopenia after Transient Pancytopenia Induced by Short-Term Concomitant Radiotherapy and Temozolomide

We describe long-lasting and incompletely resolved thrombocytopenia after transient profound pancytopenia in a 62-year-old female patient with glioblastoma after short-term radiotherapy with temozolomide. Pancytopenia was present for more than 4 weeks and thrombocytopenia for more than 6 months, without platelet recovery to normal levels.

LEARNING POINTS

Some patients may experience severe haematological manifestations after even short-term radiotherapy with temozolomide.In everyday practice, clinical models precisely predicting the haematological toxicity of concomitant treatment with temozolomide and radiotherapy is necessary, especially in countries where genetic tests are not available.Incomplete recovery of the cells of a particular bloodline over a long period may necessitate permanent discontinuation of chemotherapy or radiotherapy.

Leukopenia is a biomarker for effective temozolomide dosing and predicts overall survival of patients with glioblastoma

The median survival time of patients with glioblastoma is 14-16 months with a 5-year overall survival rate of 9.8%. Standard of care treatment includes radiation with concomitant temozolomide followed by cyclic temozolomide. If the patient develops myelosuppression (thrombocytopenia, leukopenia or anemia), the dose of temozolomide is reduced or stopped to avoid bleeding or infections. Recent studies have demonstrated that mild leukopenia is associated with increased overall survival in patients with glioblastoma. To confirm prior results showing that leukopenia is associated with increased overall survival as a primary outcome in patients with glioblastoma, the present study retrospectively collected complete blood counts from 141 patients with glioblastoma treated at the Beth Israel Deaconess Medical Center (Boston, USA) between January 2012 and December 2017. According to Kaplan-Meier analysis with a log-rank test, the presence of leukopenia was associated with increased overall survival (P=0.008). Furthermore, patients with grade 2 leukopenia (Common Terminology Criteria for Adverse Events version 5.0) survived longer than those without myelosuppression (P=0.024). There was no difference in overall survival between patients with grade 1, 3 or 4 leukopenia and those without myelosuppression. Leukopenia was associated with longer survival independent of age or extent of surgery in Cox proportional hazards regression modeling (P=0.00205). A possible interpretation is that grade 2 leukopenia is a biomarker of adequate temozolomide dosing in a population with diverse DNA repair function, which may be the consequence of variable O⁶-methylguanine-DNA methyltransferase activity. A prospective dose escalation trial is necessary to determine if treatment-induced leukopenia is beneficial for all patients receiving temozolomide.

Sex difference of mutation clonality in diffuse glioma evolution

BACKGROUND

Sex differences in glioma incidence and outcome have been previously reported but remain poorly understood. Many sex differences that affect the cancer risk were thought to be associated with cancer evolution.

METHODS

In this study, we used an integrated framework to infer the timing and clonal status of mutations in ~600 diffuse gliomas from The Cancer Genome Atlas (TCGA) including glioblastomas (GBMs) and low-grade gliomas (LGGs), and investigated the sex difference of mutation clonality.

RESULTS

We observed higher overall and subclonal mutation burden in female patients with different grades of gliomas, which could be largely explained by the mutations of the X chromosome. Some well-established drivers were identified showing sex-biased clonality, such as CDH18 and ATRX. Focusing on glioma subtypes, we further found a higher subclonal mutation burden in females than males in the majority of glioma subtypes, and observed opposite clonal tendency of several drivers between male and female patients in a specific subtype. Moreover, analysis of clinically actionable genes revealed that mutations in genes of the mitogen-activated protein kinase (MAPK) signaling pathway were more likely to be clonal in female patients with GBM, whereas mutations in genes involved in the receptor tyrosine kinase signaling pathway were more likely to be clonal in male patients with LGG.

CONCLUSIONS

The patients with diffuse glioma showed sex-biased mutation clonality (eg, different subclonal mutation number and different clonal tendency of cancer genes), highlighting the need to consider sex as an important variable for improving glioma therapy and clinical care.

Deleterious impact of a generic temozolomide formulation compared with brand-name product on the kinetic of platelet concentration and survival in newly diagnosed glioblastoma

Chemo-induced thrombocytopenia is a limiting toxicity among patients receiving temozolomide (TMZ) as first-line treatment for glioblastoma. We aimed to compare early platelet concentration kinetics, hematological safety profile, and impact on survival following the initiation of either the brand-name or a generic TMZ formulation. A retrospective trial was conducted in patients suffering from newly diagnosed glioblastoma. Patients were treated with TMZ at 75 mg/m² per day during six weeks, concomitantly with radiotherapy. Platelet concentration was collected each week. Primary endpoint was to perform a linear mixed-effect model of platelet concentration kinetic over weeks. A total of 147 patients were included as follows: 96 received the brand-name TMZ, and 51 received a generic TMZ formulation. Exposition to the generic was a significant variable that negatively influenced the platelet kinetics in the radiotherapy and concomitant TMZ phase, P = 0.02. Grade ≥3 chemo-induced thrombocytopenia was more frequent in the generic group: 19.6% [95% CI 8.7-30.5%] vs 3.1% [0-6.6%], P = 0.001. Exposition to the generic formulation of TMZ led to increase early treatment discontinuation due to TMZ-induced thrombocytopenia and was a worsening independent prognostic factor on overall survival: adjusted HR 1.83 [1.21-2.8], P = 0.031. These data suggest that exposition to a generic formulation of TMZ vs the brand-name product is associated with higher early platelet decrease leading to clinically relevant impacts on treatment schedule in glioblastoma. Further prospective trials are needed to confirm these results.

The FDA NIH Biomarkers, EndpointS, and other Tools (BEST) resource in neuro-oncology

In early 2016, the FDA and the National Institutes of Health (NIH) published the first version of the glossary included in the Biomarkers, EndpointS, and other Tools (BEST) resource.1 The BEST glossary was constructed to harmonize and clarify terms used in translational science and medical product development and to provide a common language used for communication by those agencies. It is considered a "living" document that will be updated in the future. This review will discuss the main biomarker and clinical outcome categories contained in the BEST glossary as they apply to neuro-oncology, as well as the overlapping and hierarchical relationships among them.

Good tolerability of maintenance temozolomide in glioblastoma patients after severe hematological toxicity during concomitant radiotherapy and temozolomide treatment: report of two cases

Glioblastoma is the most common and aggressive primitive brain tumor in adults. Temozolomide (TMZ) administered daily with radiation therapy, followed by adjuvant TMZ has become the standard treatment. Although TMZ treatment has been considered to have a low toxicity profile, studies have noted the development of a severe myelosuppression, especially during the concomitant treatment; this toxicity may in some cases be prolonged and consequently treatment must be definitively discontinued. We analyzed two cases treated at our oncological center who developed severe and prolonged hematological toxicity during concomitant chemoradiotherapy treatment with TMZ. Hypothesizing that radiation therapy and daily TMZ could be the major causes of severe hematological toxicity during the concomitant phase, we decided to treat both patients with maintenance TMZ at the time of recovery of hematological values. Patients showed good tolerability without important myelosuppression. In conclusion, we suggest that glioblastoma patients with severe myelotoxicity during daily TMZ and radiation therapy be treated with maintenance TMZ at the time of blood value recovery.

The association between BMI and BSA-temozolomide-induced myelosuppression toxicities: a correlative analysis of NRG oncology RTOG 0525

Background

Fearing increased myelotoxicity, many practitioners adjust the body surface area (BSA)-calculated doses in obese patients. Regarding temozolomide (TMZ), a prior study suggested men with a BSA >2 m² may experience increased toxicity; however, surprisingly, the inverse observation was noted in women, ie, BSA <2 m² was associated with higher toxicity. To further clarify this issue, data derived from a large clinical trial were analyzed.

Methods

The incidence of grade 3 and 4 myelotoxicity in a newly diagnosed glioblastoma phase 3 trial (RTOG 0525) was statistically correlated with BMI and separately with BSA. All patients received radiation and TMZ followed by adjuvant standard dose TMZ vs dose-dense TMZ; dosing regimen-associated myelotoxicity and BMI/BSA were analyzed separately. Obesity was defined as a BMI ≥30.

Results

There was no statistically significant correlation between gender and BSA and the occurrence of myotoxicities. For the standard arm, surprisingly the incidence of grade 3/4 myotoxicities in patients with a BMI <30 was significantly higher than in patients with a BMI ≥30 (12% vs 1%, odds ratio [OR] 12.5, P < .001). There was no significant difference between obese and nonobese patients (BMI "cut-point" of 30) in the dose-dense arm (OR = 0.9, 95% confidence interval: 0.4-1.6). The grade hematological 3/4 toxicity rate was significantly higher in women vs men (14% vs 8%) P = .009 in spite of the lack of association between gender and BSA or BMI.

Conclusion

TMZ dosing based on actual BSA is recommended with the caveat that woman are likely at higher toxicity risk.

Clinical correlates of severe thrombocytopenia from temozolomide in glioblastoma patients

BACKGROUND/AIM

This study was conducted retrospectively to evaluate rates of thrombocytopenia and their clinical impact during chemo-radiotherapy for glioblastomas and to elucidate associated clinical factors.

METHODS

A total of 64 patients who received temozolomide chemotherapy at our institution was included; 35 patients received full-dose chemo-radiotherapy as per the STUPP protocol (Group A), and 9 patients received abbreviated radiotherapy with concurrent chemotherapy (Group B). Twenty patients received temozolomide alone with an intended 12 cycles of therapy for first relapse at least 6 months after completion of adjuvant chemotherapy (Group C).

RESULTS

In Group A, 27 of 35 (77%) patients completed the chemo-radiotherapy phase; 14% had grade 3-4 thrombocytopenia leading to discontinuation. Of 27 patients, 16 (59%) completed adjuvant chemotherapy. There were no grade 3-4 thrombocytopenias, but 4% discontinued due to grade 2 thrombocytopenias. In Group B, four of nine (45%) patients completed the chemo-radiotherapy phase; 11% had grade 3-4 thrombocytopenias and discontinued treatment. Three of four (75%) patients completed adjuvant chemotherapy. Of these, 75% had grade 3-4 thrombocytopenias, but none discontinued. Finally, in Group C, 8 of 20 (40%) patients completed, with 10% discontinuing due to thrombocytopenias and the rest due to disease progression. In exploratory analyses, being female increased the risk of myelosuppresion, and there was a trend noticed in patients having a higher body surface area.

CONCLUSION

Our toxicity data were within range of the literature. We identified the group of patients that have increased thrombocytopenia risk. Larger pooled retrospective series and prospective studies are required.

Early platelet variation during concomitant chemo-radiotherapy predicts adjuvant temozolomide-induced thrombocytopenia in newly diagnosed glioblastoma patients

PURPOSE

Temozolomide (TMZ) is known to induce thrombocytopenia but no early predictive test has yet been clearly established. The aim of the study was to retrospectively identify and validate a threshold of early platelet variation predicting TMZ-induced thrombocytopenia during the TMZ phase in patients treated according to the Stupp protocol for glioblastoma.

METHODS

A training set was used to analyze variations in platelet count occurring from the first week (W1) to week 6 (W6) during radiotherapy. Our aim was to identify the most relevant platelet decrease associated with TMZ-induced thrombocytopenia ≤ 100 G/L at day 28 during the TMZ phase. The performance of the threshold was confirmed in an independent validation set.

RESULTS

Overall, 147 patients were included, 85 and 62 in the training and validation sets, respectively. Twenty-seven patients (18%) experienced at least one TMZ-induced thrombocytopenia in the TMZ phase. A platelet decrease at W6 ≥ 35% (∆W6 ≥ 35%) was identified as the best predictive variation with an AUC of 0.83, a sensitivity of 65%, and a specificity of 96%. In the validation set, ∆W6 ≥ 35% platelet variation was identified as an independent marker of TMZ-induced thrombocytopenia during the TMZ phase (OR 15.23 (95% CI 3.5-107.5)) corresponding to sensitivity of 77% (66-87%), specificity of 73% (62-84%), a positive predictive value of 42% (29-54%), and a negative predictive value of 92% (86-99%).

CONCLUSION

Platelet decrease at W6 ≥ 35% during the RT-TMZ phase is an early and simple predictive marker of clinically relevant TMZ-induced thrombocytopenia during TMZ maintenance.

The Prognostic Roles of Gender and O6-Methylguanine-DNA Methyltransferase Methylation Status in Glioblastoma Patients: The Female Power

BACKGROUND

Clinical and molecular factors are essential to define the prognosis in patients with glioblastoma (GBM). O6-methylguanine-DNA methyltransferase (MGMT) methylation status, age, Karnofsky Performance Status (KPS), and extent of surgical resection are the most relevant prognostic factors. Our investigation of the role of gender in predicting prognosis shows a slight survival advantage for female patients.

METHODS

We performed a prospective evaluation of the Project of Emilia Romagna on Neuro-Oncology (PERNO) registry to identify prognostic factors in patients with GBM who received standard treatment.

RESULTS

A total of 169 patients (99 males [58.6%] and 70 females [41.4%]) were evaluated prospectively. MGMT methylation was evaluable in 140 patients. Among the male patients, 36 were MGMT methylated (25.7%) and 47 were unmethylated (33.6%); among the female patients, 32 were methylated (22.9%) and 25 were unmethylated (17.9%). Survival was longer in the methylated females compared with the methylated males (P = 0.028) but was not significantly different between the unmethylated females and the unmethylated males (P = 0.395). In multivariate analysis, gender and MGMT methylation status considered together (methylated females vs. methylated males; hazard ratio [HR], 0.459; 95% confidence interval [CI], 0.242-0.827; P = 0.017), age (HR, 1.025; 95% CI, 1.002-1.049; P = 0.032), and KPS (HR, 0.965; 95% CI, 0.948-0.982; P < 0.001) were significantly correlated with survival.

CONCLUSIONS

Survival was consistently longer among MGMT methylated females compared with males. Gender can be considered as a further prognostic factor.

Impact of concurrent versus adjuvant chemotherapy on the severity and duration of lymphopenia in glioma patients treated with radiation therapy

Prolonged severe lymphopenia has been shown to persist beyond a year in glioma patients after radiation therapy (RT) with concurrent and adjuvant chemotherapy. This study examines the differential impact of concurrent versus adjuvant chemotherapy on lymphopenia after RT. WHO grade II-III glioma patients who received RT with concurrent and/or adjuvant chemotherapy from 2007 to 2016 were retrospectively analyzed. Concurrent chemotherapy was temozolomide (TMZ), and adjuvant chemotherapy was either TMZ or procarbazine/lomustine/vincristine (PCV). Absolute lymphocyte count (ALC) was analyzed at baseline, 1.5, 3, 6, and 12 months after the start of RT. Univariable and multivariable logistic regression were used to identify the clinical variables in predicting acute or late lymphopenia. There were 151 patients with evaluable ALC: 91 received concurrent and adjuvant TMZ (CRT + ADJ), 32 received only concurrent TMZ (CRT), and 28 received only adjuvant TMZ or PCV (ADJ). There were 9 (10%) versus 6 (19%) versus 0 (0%) cases of grade 3 lymphopenia (ALC < 500/mm³) at 6 weeks and 4 (6%) versus 0 (0%) versus 3 (17%) cases at 12 months in CRT + ADJ, CRT and ADJ groups, respectively. On multivariable analyses, concurrent chemotherapy (odds ratio [OR] 72.3, p < 0.001), female sex (OR 10.8, p < 0.001), and older age (OR 1.06, p = 0.002) were the most significant predictors for any grade ≥ 1 lymphopenia (ALC < 1000/mm³) at 1.5 months. Older age (OR 1.08, p = 0.02) and duration of adjuvant chemotherapy (OR 1.19, p = 0.003) were significantly associated with grade ≥ 1 lymphopenia at 12 months. Thus, concurrent chemotherapy appears as the dominant contributor to the severity of acute lymphopenia after RT in WHO grade II-III glioma patients, and duration of adjuvant chemotherapy appears as the key factor to prolonged lymphopenia.

A Model to Predict the Feasibility of Concurrent Chemoradiotherapy With Temozolomide in Glioblastoma Multiforme Patients Over Age 65

OBJECTIVES

It is controversial whether concurrent chemoradiotherapy (CRT) with temozolomide is feasible and beneficial in elderly patients with glioblastoma.

MATERIALS AND METHODS

Retrospective analysis of 74 elderly glioblastoma patients (65 y and above) treated with concurrent CRT with temozolomide. Factors influencing prognosis and feasibility of CRT were investigated.

RESULTS

The median overall survival was 11.3 months. Univariate analysis showed a significant difference in median overall survival for cumulative dose of concurrent temozolomide (optimal cutoff, 2655 mg/m; 13.9 mo for >2655 mg/m vs. 4.9 mo for ≤2655 mg/m; P=0.0216, adjusted for multiple testing). Furthermore, cumulative dose of concurrent temozolomide >2655 mg/m was a significant independent prognostic parameter in multivariate analysis (hazard ratio, 0.33; P=0.002). Hematotoxicity was the most common cause of treatment interruption or discontinuation in patients with an insufficient cumulative temozolomide dose. Prognostic factors for successful performance of CRT with a cumulative dose of concurrent temozolomide >2655 mg/m were female sex (odds ratio [OR], 0.174; P=0.006), age (OR, 0.826 per year; P=0.017), and pretreatment platelet count (OR, 1.013 per 1000 platelets/µL; P=0.001). For easy clinical application of the model an online calculator was developed, which is available at http://www.OldTMZ.com.

CONCLUSIONS

The probability of successful performance of concurrent CRT with temozolomide can be estimated based on the patient's age, sex, and pretreatment platelet count using the model developed in this study. Thus, a subgroup of elderly glioblastoma patients suitable for chemoradiation with temozolomide can be identified.

Pharmacotherapy of Glioblastoma: Established Treatments and Emerging Concepts

Glioblastoma is the most frequent malignant brain tumor and is characterized by poor prognosis, increased invasiveness, and high recurrence rates. Standard treatment for glioblastoma includes maximal safe surgical resection, radiation, and chemotherapy with temozolomide. Despite treatment advances, only 15-20% of glioblastoma patients survive to 5 years, and no therapies have demonstrated a durable survival benefit in recurrent disease. In the last 10 years, significant advances in knowledge of the biology and molecular pathology of the malignancy have opened the way to new treatment options. Clinical management of patients (pseudo-progressions, side effects of therapies, best supportive care, centralization in expertise care centers) has improved. In brain tumors, such as in other solid tumors, we have entered an era of immune-oncology. Immunotherapy seems to have an acceptable safety and tolerability profile in the recurrent setting and is under investigation in clinical trials in newly diagnosed glioblastoma patients. This review focuses on novel targeted therapies recently developed for the management of newly diagnosed and recurrent glioblastomas.

MGMT gene variants, temozolomide myelotoxicity and glioma risk. A concise literature survey including an illustrative case

Temozolomide may cause thrombocytopenia or neutropenia in 3-4% of glioblastoma patients, respectively. However, pancytopenia is rarely reported. MGMT (O6-methylguanine-DNA-methyltransferase) enzyme repairs temozolomide-induced DNA mutations and associates both with antitumour efficacy and myelosuppression. Many studies on the effects of MGMT gene-methylation on temozolomide's effects exist, but much fewer publications concerning MGMT variants were documented. A full sequencing of the MGMT gene was performed in a female glioblastoma patient, who developed pancytopenia following temozolomide treatment. Results indicated the presence of all the rs2308321 (I143 V), rs2308327 (K178R) and rs12917 (L84F) MGMT-variants, which were previously associated with temozolomide myelotoxicity. rs12917 (L84F) variant was reported as associating with lesser risk of gallbladder tumours, yet with higher risk of non-Hodgkin lymphomas related with exposure to chlorinated solvents or hair dyes. DNA repair proteins may exert diverging effects on DNA injuries caused by different chemicals and therefore exerting complex effects on myelotoxicity, antitumour activity and carcinogenesis.

Toward Personalized Targeted Therapeutics: An Overview

In neuro-oncology, there has been a movement towards personalized medicine, or tailoring treatment to the individual patient. Ideally, tumor and patient evaluations would lead to the selection of the best treatment (based on tumor characterization) and the right dosing schedule (based on patient characterization). The recent advances in the molecular analysis of glioblastoma have created optimism that personalized targeted therapy is within reach. Although our understanding of the molecular complexity of glioblastoma has increased over the years, the path to developing effective targeted therapeutic strategies is wrought with many challenges, as described in this review. These challenges include disease heterogeneity, clinical and genomic patient variability, limited number of effective treatments, clinical trial inefficiency, drug delivery, and clinical trial support and accrual. To confront these challenges, it will be imperative to devise innovative and adaptive clinical trials in order to accelerate our efforts in improving the outcomes for our patients who have been in desperate need.

Persistent bone marrow depression following short-term treatment with temozolomide

Temozolomide (TMZ) is, in combination with radiotherapy (RT), the treatment of choice for glioblastoma multiforme. Although generally well tolerated, haematological side effects are observed in approximately 1-10% of patients receiving TMZ. We report a case of a patient who developed severe bone marrow failure (BMF) after only 3 weeks of concomitant TMZ. The BMF was grave with no signs of improvement for 12 months, resulting in more than 100 transfusions of blood cells.

Clinical and Genetic Factors Associated With Severe Hematological Toxicity in Glioblastoma Patients During Radiation Plus Temozolomide Treatment: A Prospective Study

BACKGROUND

Temozolomide (TMZ) administered daily with radiation therapy (RT) for 6 weeks, followed by adjuvant TMZ for 6 cycles, is the standard therapy for newly diagnosed glioblastoma (GBM) patients. Although TMZ is considered to be a safe drug, it has been demonstrated to cause severe myelotoxicity; in particular, some case reports and small series studies have reported severe myelotoxicity developing during TMZ and concomitant RT. We performed a prospective study to analyze the incidence of early severe myelotoxicity and its possible clinical and genetic factors.

PATIENTS AND METHODS

From November 2010 to July 2012, newly diagnosed GBM patients were enrolled. They were eligible for the study if they met the following criteria: pathologically proven GBM, age 18 years and older, an Eastern Cooperative Oncology Group performance status of 0 to 2, adequate renal and hepatic function, and adequate blood cell counts before starting TMZ plus RT. Grading of hematologic toxicity developing during radiation and TMZ was based on the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. Clinical factors from all patients were recorded. The methylation status and polymorphic variants of O-methylguanine-DNAmethyl-transferase gene in peripheral blood mononuclear cells, and polymorphic genetic variants of genes involved in the pharmacokinetics and pharmacodynamics of TMZ, were analyzed. For genetic analyses, patients with toxicity were matched (1:2) for age, performance status, anticonvulsants, and proton pump inhibitors with patients without myelotoxicity.

RESULTS

We enrolled 87 consecutive GBM patients: 32 women and 55 men; the average age was 60 years. During TMZ and RT, 4 patients (5%) showed grade 3-4 myelotoxicity, and its median duration was 255 days. Predictor factors of severe myelotoxicity were female sex, pretreatment platelet count of ≤3,00,000/mm, methylated O-methylguanine-DNA methyltransferase promoter in the hematopoietic cell system, and specific polymorphic variants of the cytochrome P450 oxidoreductase and methionine adenosyltransferase 1A genes.

CONCLUSIONS

Although we studied a small population, we suggest that both clinical and genetic factors might simultaneously be associated with severe myelosuppression developed during TMZ plus RT. However, our results deserve validation in larger prospective studies and, if the factors associated with severe myelotoxicity are validated, dose adjustments of TMZ for those patients may reduce the risk of severe myelotoxicity during the concomitant treatment.

Bevacizumab, temozolomide, and radiotherapy for newly diagnosed glioblastoma: comprehensive safety results during and after first-line therapy

BACKGROUND

The proposed use of bevacizumab with radiotherapy/temozolomide for newly diagnosed glioblastoma raised potential safety concerns. Bevacizumab has been linked with stroke, bleeding events, and wound-healing complications in other tumor types; these events are of particular concern for glioblastoma (highly vascular tumors that are usually resected). Published data on the interaction of bevacizumab with radiotherapy/temozolomide are also limited. We report safety data from a phase III randomized trial (Avastin in Glioblastoma), focusing on these considerations.

METHODS

Eligible patients received: radiotherapy and temozolomide plus bevacizumab/placebo, 6 cycles; a 4-week treatment break; temozolomide plus bevacizumab/placebo, 6 cycles; and bevacizumab/placebo until progression. Data on adverse events (AEs) were collected throughout.

RESULTS

Bevacizumab-treated patients (n = 461) had a longer median safety follow-up time (12.3 vs 8.5 mo), and a higher proportion completed 6 cycles of maintenance temozolomide (64.6% vs 36.9%) versus placebo (n = 450). The incidences of relevant AEs (bevacizumab vs placebo, respectively) were: arterial thromboembolic events (5.9% vs 1.6%); cerebral hemorrhage (3.3% vs 2.0%); wound-healing complications (6.9% vs 4.7%); thrombocytopenia (34.1% vs 27.3%); radiotherapy-associated skin injury (8.2% vs 9.3%); alopecia (39.0% vs 36.0%); gastrointestinal perforation (including gastrointestinal abscesses and fistulae, 1.7% vs 0.4%); and radiotherapy-associated injury (0.4% vs 0.0%). Overall, 15.8% and 23.8% of bevacizumab- and placebo-treated patients had surgery (including biopsy) after progression. Within 30 days of postprogression surgery, AE incidence was 10.9% (bevacizumab) and 23.4% (placebo).

CONCLUSION

The safety profile was consistent with that expected from radiotherapy/temozolomide plus bevacizumab. The increased AE incidence with bevacizumab did not impact patients' ability to receive standard-of-care treatment or to undergo further surgery.

The role of temozolomide in the management of patients with newly diagnosed anaplastic astrocytoma: a comparison of survival in the era prior to and following the availability of temozolomide

Adding temozolomide (TMZ) to radiation for patients with newly-diagnosed anaplastic astrocytomas (AAs) is common clinical practice despite the lack of prospective studies demonstrating a survival advantage. Two retrospective studies, each with methodologic limitations, provide conflicting advice regarding treatment. This single-institution retrospective study was conducted to determine survival trends in patients with AA. All patients ≥18 years with newly-diagnosed AA treated at Johns Hopkins from 1995 to 2012 were included. As we incorporated TMZ into high-grade glioma treatment regimens in 2004, patients were divided into pre-2004 and post-2004 groups for analysis. Clinical, radiographic, and pathologic data were collected. Median overall survival (OS) was calculated using Kaplan-Meier estimates. A total of 196 patients were identified; 74 pre-2004 and 122 post-2004; mean age 47 ± 15 years; 57 % male; 87 % white, 69 % surgical debulking. Mean RT dose 5676 + 746 cGy; duration of concurrent chemoradiation 5.8 ± 0.8 weeks; and mean adjuvant chemotherapy 4.3 + 2.8 cycles. Baseline prognostic factors did not differ between groups. Chemotherapy was administered to 12 % of patients pre-2004 (TMZ = 1, procarbazine, lomustine and vincristine = 2, carmustine wafer = 6) and 94 % post-2004 (TMZ in all, p < 0.001). Median OS was 32 months (95 % CI 23-43). Survival was longer in the post-2004 cohort (37 mo, 24-64) than pre-2004 (27 mo, 19-40; HR 0.75, 0.53-1.06, p = 0.11). Multivariate analysis controlling for age, Karnofsky performance status, and extent of resection revealed a 36 % reduced risk of death (HR 0.64, 0.44-0.91, p = 0.015) in patients treated post-2004. This retrospective review found survival in newly diagnosed patients with AA improved with the addition of temozolomide to standard radiation. Until prospective randomized phase III data are available, these data support the practice of incorporating TMZ in the management of newly-diagnosed AA.

Can dosimetric parameters predict acute hematologic toxicity in rectal cancer patients treated with intensity-modulated pelvic radiotherapy?

Background

To identify dosimetric parameters associated with acute hematologic toxicity (HT) in rectal cancer patients undergoing concurrent chemotherapy and intensity-modulated pelvic radiotherapy.

Methods

Ninety-three rectal cancer patients receiving concurrent capecitabine and pelvic intensity-modulated radiation therapy (IMRT) were analyzed. Pelvic bone marrow (PBM) was contoured for each patient and divided into three subsites: lumbosacral spine (LSS), ilium, and lower pelvis (LP). The volume of each site receiving 5–40 Gy (V 5, V10, V15, V20, V30, and V40, respectively) as well as patient baseline clinical characteristics was calculated. The endpoint for hematologic toxicity was grade ≥ 2 (HT2+) leukopenia, neutropenia, anemia or thrombocytopenia. Logistic regression was used to analyze correlation between dosimetric parameters and grade ≥ 2 hematologic toxicity.

Results

Twenty-four in ninety-three patients experienced grade ≥ 2 hematologic toxicity. Only the dosimetric parameter V40 of lumbosacral spine was correlated with grade ≥ 2 hematologic toxicity. Increased pelvic lumbosacral spine V40 (LSS-V40) was associated with an increased grade ≥ 2 hematologic toxicity (p = 0.041). Patients with LSS-V40 ≥ 60 % had higher rates of grade ≥ 2 hematologic toxicity than did patients with lumbosacral spine V40 < 60 % (38.3 %, 18/47 vs.13 %, 6/46, p =0.005). On univariate and multivariate logistic regression analysis, lumbosacral spine V40 and gender was also the variable associated with grade ≥ 2 hematologic toxicity. Female patients were observed more likely to have grade ≥ 2 hematologic toxicity than male ones (46.9 %, 15/32 vs 14.8 %, 9/61, p =0.001).

Conclusions

Lumbosacral spine -V40 was associated with clinically significant grade ≥ 2 hematologic toxicity. Keeping the lumbosacral spine -V40 < 60 % was associated with a 13 % risk of grade ≥ 2 hematologic toxicity in rectal cancer patients undergoing concurrent chemoradiotherapy.

Medical management of brain tumors and the sequelae of treatment

Patients with malignant brain tumors are prone to complications that negatively impact their quality of life and sometimes their overall survival as well. Tumors may directly provoke seizures, hypercoagulable states with resultant venous thromboembolism, and mood and cognitive disorders. Antitumor treatments and supportive therapies also produce side effects. In this review, we discuss major aspects of supportive care for patients with malignant brain tumors, with particular attention to management of seizures, venous thromboembolism, corticosteroids and their complications, chemotherapy including bevacizumab, and fatigue, mood, and cognitive dysfunction.

Temozolomide-related hematologic toxicity

Temozolomide (TMZ) is an oral alkylating agent used for the treatment of recurrent or newly diagnosed malignant gliomas with significant survival benefit. TMZ is generally well tolerated and safe. The most common side effects are mild to moderate, and are represented by fatigue, nausea, vomiting, thrombocytopenia, and neutropenia. However severe hematologic adverse events (HAEs), including myelodysplastic syndrome and aplastic anemia, have also been reported. In this review we present an overview of the available literature of HAEs after exposure to TMZ.