Phase II Trial of Alisertib in Combination with Irinotecan and Temozolomide for Patients with Relapsed or Refractory Neuroblastoma

PURPOSE

In phase I testing, alisertib tablets with irinotecan and temozolomide showed significant antitumor activity in patients with neuroblastoma. This study sought to confirm activity of this regimen; evaluate an alisertib oral solution; and evaluate biomarkers of clinical outcomes.

PATIENTS AND METHODS

We conducted a two-stage phase II trial of alisertib tablets (60 mg/m2/dose × 7 days), irinotecan (50 mg/m2/dose i.v. × 5 days), and temozolomide (100 mg/m2/dose orally × 5 days) in patients with relapsed or refractory neuroblastoma. The primary endpoint was best objective response. A separate cohort was treated with alisertib at 45 mg/m2 using oral solution instead of tablets. Exploratory analyses sought to identify predictors of toxicity, response, and progression-free survival (PFS) using pooled data from phase I, phase II, and oral solution cohorts.

RESULTS

Twenty and 12 eligible patients were treated in the phase II and oral solution cohorts, respectively. Hematologic toxicities were the most common adverse events. In phase II, partial responses were observed in 19 evaluable patients (21%). The estimated PFS at 1 year was 34%. In the oral solution cohort, 3 patients (25%) had first cycle dose-limiting toxicity (DLT). Alisertib oral solution at 45 mg/m2 had significantly higher median C max and exposure compared with tablets at 60 mg/m2. Higher alisertib trough concentration was associated with first cycle DLT, whereas MYCN amplification was associated with inferior PFS.

CONCLUSIONS

This combination shows antitumor activity, particularly in patients with MYCN nonamplified tumors. Data on an alisertib oral solution expand the population able to be treated with this agent.

Chemical Probes for Human UDP-Glucuronosyltransferases: A Comprehensive Review

UGTs play crucial roles in the metabolism and detoxification of both endogenous and xenobiotic compounds. The key roles of UGTs in human health have garnered great interest in the design and development of specific probes for human UGTs. However, in contrast to other human enzymes, the probe substrates for human UGTs are rarely reported, owing to the highly overlapping substrate specificities of UGTs and the lack of the integrated crystal structures of UGTs. Over the past decades, many efforts are made to develop specific probe substrates for UGTs and use them in both basic research and drug discovery. This review focuses on recent progress in the development of probe substrates for UGTs and their biomedical applications. A long list of chemical probes for UGTs, including non-fluorescent and fluorescent probes along with their structural information and kinetic parameters, are prepared and analyzed. Additionally, challenges and future directions in this field are highlighted in the final section. All information and knowledge presented in this review provide practical tools/methods for measuring UGT activities in complex biological samples, which will be very helpful for rapid screening and characterization of UGT modulators, and for exploring the relevance of UGT enzymes to human diseases.

Distribution of uridine diphosphate glucuronosyltransferase 1A polymorphisms and their role in irinotecan-induced toxicity in patients with cancer

Uridine diphosphate glucuronosyltransferase 1A (UGT1A1), which affects irinotecan metabolism, has been associated with severe adverse reactions in patients with cancer treated with irinotecan. However, neither large-scale analysis of the distribution of UGT1A1 polymorphisms, nor standardized assessment of how UGT1A1 polymorphisms affect irinotecan treatment has been performed in China. The aim of the present study was to investigate the distribution of UGT1A1 polymorphisms (*28 and *6) in 2,093 Chinese patients with cancer who were treated with irinotecan from more than 15 hospitals in Shandong, to examine how the coexistence of UGT1A1*6 and UGT1A1*28 alleles may be able to predict toxicities induced by irinotecan in 105 of the patients, and to search for other relevant risk factors. The distribution of the genotypes was as follows: TA₆/TA₆ (1,601, 76.5%), TA₆/TA₇ (463, 22.1%) and TA₇/TA₇ (29, 1.4%) for UGT1A1*28 (n=2,093); and G/G (286, 66.4%), G/A (124, 28.8%) and A/A (21, 4.9%) for UGT1A1*6 (n=431). The most frequent severe hematological toxicity was neutropenia, and the predominant non-hematological toxicities were diarrhea and cholinergic syndrome. In toxicity comparisons, grade 3–4 leukopenia and neutropenia were significantly higher in TA₆/TA₇ compared with TA₆/TA₆ (P<0.05). The UGT1A1*6 polymorphism was associated with a higher risk of severe diarrhea and total adverse drug reactions (P<0.05). Logistic regression showed that the UGT1A1*6 genotype was an independent predictor of severe diarrhea. These findings suggested that the UGT1A1*28 and UGT1A1*6 genotypes may be associated with irinotecan-induced severe toxicity, and clarified the clinical importance of UGT1A1 polymorphisms, particularly UGT1A1*6, regarding irinotecan therapy in Chinese patients.

Relationship between UGT1A1*6/*28 gene polymorphisms and the efficacy and toxicity of irinotecan-based chemotherapy

Purpose

A retrospective study was performed to analyze the relationship between uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) *6/*28 gene polymorphisms and adverse reactions associated with irinotecan (CPT-11)-based chemotherapy. The correlation between UGT1A1 polymorphisms and the clinical efficacy of CPT-11 was also analyzed, along with the influence of age and tumor type.

Patients and methods

Patients administered a CPT-11-based regimen in the Beijing Cancer Hospital from April 2015 to September 2016 were included in our study (n=81). Blood samples for detecting UGT1A1 were collected from each patient after various administration regimens.

Results

Colorectal cancer patients with the UGT1A1*6 mutant genotype had a significantly higher risk of severe delayed diarrhea than that of wild-type individuals when administered a CPT-11 dose ≥130 mg/m² (P=0.042); the same phenomenon was observed when the UGT1A1*6 and UGT1A1*28 mutant genotypes were considered together (P=0.028). However, in lung cancer patients administered a low dose of CPT-11, UGT1A1*6/*28 variants were not significantly associated with severe neutropenia or delayed diarrhea. Furthermore, adult patients with the UGT1A1*6 mutation were more likely to develop severe delayed diarrhea than did wild-type adults (P=0.013); however, the difference was not significant in elderly patients. No significant differences in tumor response were found among the different genotypes (P>0.05).

Conclusion

Thus, age and tumor type influence our ability to predict adverse reactions based on UGT1A1 gene polymorphisms in cancer patients. Further, UGT1A1 gene polymorphisms are not correlated with the efficacy of CPT-11-based regimens.

Phase I/II study of (131)I-MIBG with vincristine and 5 days of irinotecan for advanced neuroblastoma

Background:

¹³¹I-metaiodobenzylguanidine (MIBG) is an active radiopharmaceutical in neuroblastoma. A previous study demonstrated that MIBG could be combined with vincristine and prolonged irinotecan, although 25% of first courses had grade 3 diarrhoea. The current phase I/II study evaluated MIBG with vincristine and 5 days of higher-dose irinotecan.

Methods:

Patients 1–30 years old with advanced neuroblastoma were eligible. Patients received cefixime on days −1 to +6, irinotecan (50 mg m⁻² per dose IV) on days 0–4, vincristine (2 mg m⁻²) on day 0, MIBG (555 or 666 MBq kg⁻¹) on day 1, and peripheral blood stem cells on day 13. UGT1A1 genotyping was performed in consenting patients.

Results:

Thirty-two patients (12 phase I ; 20 phase II) received 42 courses. No dose-limiting toxicities were seen during dose escalation and the recommended administered activity was 666 MBq kg⁻¹. Myelosuppression and diarrhoea were the most common toxicities, with grade 3 diarrhoea in 6% of first courses. Patients homozygous for UGT1A1*28 had more grade 4 thrombocytopenia (80% vs 37% P=0.14). Responses (five complete and four partial) occurred in 9 out of 32 (28%) patients.

Conclusions:

MIBG (666 MBq kg⁻¹) with vincristine and this irinotecan schedule is tolerable and active, with less severe diarrhoea compared with a regimen using more protracted irinotecan.

Polymorphisms of uridine glucuronosyltransferase gene and irinotecan toxicity: low dose does not protect from toxicity

Uridine glucuronosyltransferase (UGT) gene polymorphisms have been linked to irinotecan toxicity. Our purpose was to study the association between UGT1A1*28, UGT1A7*2, and UGT1A7*3 polymorphisms and irinotecan toxicity in Greek patients receiving low-dose weekly irinotecan. Blood samples were collected for 46 patients. DNA was extracted and UGT1A1 promoter and UGT1A7 exon 1 genotyping was carried out. Laboratory tests and physical examination were performed on regular basis for the assessment of toxicity. UGT1A1*28 was significantly correlated with both haematologic and non-haematologic toxicity. Moreover, patients carrying UGT1A7 polymorphisms had significant incidence of toxicity. To conclude, UGT polymorphisms play a role in the toxicity of irinotecan, even if the drug is administered in low doses. The genotyping test may be a useful tool for the management of patients who are going to receive irinotecan.

Dose banding as an alternative to body surface area-based dosing of chemotherapeutic agents

BACKGROUND

Dose banding is a recently suggested dosing method that uses predefined ranges (bands) of body surface area (BSA) to calculate each patient's dose by using a single BSA-value per band. Thus, drugs with sufficient long-term stability can be prepared in advance. The main advantages of dose banding are to reduce patient waiting time and improve pharmacy capacity planning; additional benefits include reduced medication errors, reduced drug wastage, and prospective quality control. This study compares dose banding with individual BSA dosing and fixed dose according to pharmacokinetic criteria.

METHODS

Three BSA bands were defined: BSA<1.7 m(2), 1.7 m(2)≤ BSA<1.9 m(2), BSA ≥ 1.9 m(2) and each patient dose was calculated based on a unique BSA-value per band (1.55, 1.80, and 2.05 m(2), respectively). By using individual clearance values of six drugs (cisplatin, docetaxel, paclitaxel, doxorubicin, irinotecan, and topotecan) from 1012 adult cancer patients in total, the AUCs corresponding to three dosing methods (BSA dosing, dose banding, and fixed dose) were compared with a target AUC for each drug.

RESULTS

For all six drugs, the per cent variation in individual dose obtained with dose banding compared with BSA dosing ranged between -14% and +22%, and distribution of AUC values was very similar with both dosing methods. In terms of reaching the target AUC, there was no significant difference in precision between dose banding and BSA dosing, except for paclitaxel (32.0% vs 30.7%, respectively; P<0.05). However, precision was significantly better for BSA dosing compared with fixed dose for four out of six drugs.

CONCLUSION

For the studied drugs, implementation of dose banding should be considered as it entails no significant increase in interindividual plasma exposure.

Phase I study of vincristine, irinotecan, and ¹³¹I-metaiodobenzylguanidine for patients with relapsed or refractory neuroblastoma: a new approaches to neuroblastoma therapy trial

PURPOSE

(131)I-metaiodobenzylguanidine (MIBG) is a targeted radiopharmaceutical with activity in patients with relapsed or refractory neuroblastoma. Irinotecan is a known radiosensitizer with activity in neuroblastoma. This phase I study aimed to determine the recommended phase 2 dose of MIBG together with fixed doses of vincristine and irinotecan.

EXPERIMENTAL DESIGN

Patients 1 to 30 years old with relapsed or refractory neuroblastoma and MIBG-avid tumors were eligible. All patients had autologous hematopoietic stem cells (PBSC) available and met standard phase I organ function requirements. Irinotecan (20 mg/m(2)/dose IV) was given on days 0 to 4 and 7 to 11, with vincristine (1.5 mg/m(2) IV) on days 0 and 7. MIBG was given on day 1 following a 3 + 3 phase I dose escalation design starting at 8 mCi/kg MIBG. PBSCs were administered at dose level 8 mCi/kg for prolonged myelosuppression and for all patients at 12 mCi/kg or more.

RESULTS

Twenty-four patients evaluable for dose escalation (median age, 6.7 years; range, 1.9-26.8 years) received 1 (n = 17), 2 (n = 5), or 3 (n = 2) cycles of therapy. Myelosuppression and diarrhea were the most common toxicities. Two of 6 patients at the 18 mCi/kg dose level had dose-limiting toxicity (DLT), including one with protocol-defined DLT with prolonged mild aspartate aminotransferase elevation. Eighteen mCi/kg was the recommended phase 2 dose. Six additional patients were treated at 18 mCi/kg, with one additional DLT. Responses (2 complete and 4 partial responses) occurred in 6 of 24 (25%) evaluable patients.

CONCLUSIONS

MIBG is tolerable and active at 18 mCi/kg with standard doses of vincristine and irinotecan.

Dose escalation of intravenous irinotecan using oral cefpodoxime: a phase I study in pediatric patients with refractory solid tumors

BACKGROUND

Administration of an oral cephalosporin allowed advancement of the dosage of oral irinotecan. This study investigates whether administration of an oral cephalosporin increases the maximum tolerated dose (MTD) of intravenous irinotecan.

PROCEDURE

Irinotecan was administered intravenously on Days 1-5 and Days 8-12 of a 21-day cycle with continuous oral cefpodoxime starting 2 days prior to irinotecan. Cohorts of 3-6 pediatric patients with refractory solid tumors were enrolled at 4 dosage levels, starting at the single-agent irinotecan MTD of 20 mg/m(2) /dose.

RESULTS

The 17 evaluable patients received 39 courses of therapy. None of the patients treated with 20 mg/m(2) /dose experienced dose-limiting toxicity (DLT). One of six patients treated at 30 mg/m(2) /dose experienced dose-limiting neutropenia. Two of three patients treated with 45 mg/m(2) /dose and two of five treated with 40 mg/m(2) /dose experienced dose-limiting diarrhea, with associated dehydration and anorexia. Two unconfirmed partial responses were observed after one course in a patient with Ewing sarcoma and one with paraganglioma. A child with refractory neuroblastoma had disease stabilization through 12 courses of therapy. Median (range) systemic exposure to SN-38 at the MTD (30 mg/m(2) /dose) was 67 ng-h/mL (36 to 111 ng-h/mL).

CONCLUSIONS

The MTD of intravenous irinotecan administered on a protracted schedule was increased by 50% from 20 to 30 mg/m(2) /dose with the addition of oral cefpodoxime. The most prominent DLT remained diarrhea. High interpatient variability in irinotecan pharmacokinetics was observed; however, SN-38 exposure at the MTD was greater than most reported exposures with the 20 mg/m(2) dosage.

Optimizing therapeutic efficacy of chemopreventive agents: A critical review of delivery strategies in oral cancer chemoprevention clinical trials

Due to its characterized progression from recognized premalignant oral epithelial changes (i.e., oral epithelial dysplasia) to invasive cancer, oral squamous cell carcinoma represents an optimal disease for chemopreventive intervention prior to malignant transformation. The primary goal of oral cancer chemoprevention is to reverse, suppress, or inhibit the progression of premalignant lesions to cancer. Over the last several decades, numerous oral cancer chemoprevention clinical trials have assessed the therapeutic efficacy of diverse chemopreventive agents. The standard of care for more advanced oral dysplastic lesions entails surgical excision and close clinical follow-up due to the potential (~33%) for local recurrence at a similar or more advanced histological stage. The purpose of this review was to identify prominent oral cancer chemoprevention clinical trials, assess their overall therapeutic efficacy, and delineate effects of local versus systemic drug administration. In addition, these compiled clinical trial data present concepts for consideration in the design and conduction of future clinical trials.

A phase I, dose-finding study of sunitinib in combination with irinotecan in patients with advanced solid tumours

BACKGROUND

Sunitinib is a multitargeted, oral tyrosine kinase inhibitor with antitumour and antiangiogenic activity. We investigated the safety and pharmacokinetics of sunitinib in combination with irinotecan in patients with advanced, refractory solid tumours.

METHODS

Sunitinib was initially administered once daily at 37.5 mg per day on days 1-14 of a 21-day cycle, in which irinotecan 250 mg m(-2) was given on day 1. In a second cohort, the sunitinib dose was reduced to 25 mg per day. Blood samples were collected for pharmacokinetic studies.

RESULTS

In the sunitinib 37.5 mg per day cohort, 3 out of 10 evaluable patients had objective responses, but dose-limiting toxicities (DLTs) of neutropenia, pneumococcal sepsis, and fatigue were observed. There were no DLTs in the sunitinib 25 mg per day cohort. Paired observations of pharmacokinetic parameter values of sunitinib and irinotecan alone vs the combination did not reveal significant drug-drug interactions. The maximum tolerated dose was defined as sunitinib 25 mg per day (days 1-14) with irinotecan 250 mg m(-2) (day 1), but no activity was observed at this dose.

CONCLUSION

Although a higher sunitinib dose of 37.5 mg per day (days 1-14) with irinotecan showed preliminary evidence of antitumour activity, this dose was poorly tolerated. Therefore, this particular combination will not be pursued for further studies.

Prediction of irinotecan and 5-fluorouracil toxicity and response in patients with advanced colorectal cancer

Irinotecan and 5-fluorouracil (5-FU) are used to treat metastatic colorectal cancer. Irinotecan's active metabolite is inactivated by UDP-glucuronosyltransferase 1A1 (UGT1A1), which is deficient in Gilbert's syndrome. Irinotecan and metabolites are transported by P-glycoprotein, encoded by ABCB1. 5-FU targets folate metabolism through inhibition of thymidylate synthase (TYMS). Methylenetetrahydrofolate reductase (MTHFR) generates active folate necessary for haematopoiesis. We retrospectively genotyped 140 Swedish and Norwegian irinotecan and 5-FU-treated colorectal cancer patients from the Nordic VI clinical trial for selected variants of UGT1A1, ABCB1, TYMS and MTHFR. We found an increased risk of clinically relevant early toxicity in patients carrying the ABCB1 3435 T/T genotype, Odds ratio (OR)=3.79 (95% confidence interval (CI)=1.09–13.2), and in patients carrying the UGT1A1^*28/^*28 genotype, OR=4.43 (95% CI=1.30–15.2). Patients with UGT1A1^*28/^*28 had an especially high risk of neutropenia, OR=6.87 (95% CI=1.70–27.7). Patients who had reacted with toxicity during the first two cycles were in total treated with fewer cycles (P<0.001), and less often responded to treatment (P<0.001). Genetic variation in ABCB1 was associated with both early toxicity and lower response to treatment. Carriers of the ABCB1 1236T-2677T-3435T haplotype responded to treatment less frequently (43 vs 67%, P=0.027), and survived shorter time, OR=1.56 (95% CI=1.01–2.45).

Personalizing antiretroviral therapy: is it a reality?

The concept of personalizing antiretroviral therapy is not novel, since the complexity of the HIV patient and their therapy has always demanded consideration of the patient's 'pharmacoecology', taking into account factors such as adherence, drug-drug and food-drug interactions, underlying disease and host states, such as organ dysfunction and pregnancy. Recent advances in science have taken this one step further with the technology now available to use both a candidate and whole-genome approach to explore the genetics of host-virus interactions, as well as the pharmacogenetics of the toxicity and efficacy of antiretroviral therapy. The genetics of host-virus interactions have improved our understanding of the pathogenesis of HIV which will aid in the research and development of an HIV vaccine. Most published HIV pharmacogenetic studies have utilized a candidate gene approach. Although these types of studies have provided insight into the pathogenesis and pharmacogenetics of drug disposition, drug interactions, drug efficacy and toxicity and host-virus interactions, very few will lend themselves to a widespread clinical application. The application of HLA-B*5701 screening to prevent abacavir hypersensitivity acts as an important example of the successful widespread implementation of a pharmacogenetic test into the clinic and defines the key steps necessary for the clinical application of pharmacogenetic tests in general.