Pediatric phase 2 trial of a WEE1 inhibitor,adavosertib (AZD1775), and irinotecan for relapsed neuroblastoma,medulloblastoma, and rhabdomyosarcoma

Background

Inhibition of the WEE1 kinase by adavosertib (AZD1775) potentiates replicative stress from genomic instability or chemotherapy. This study reports the pediatric solid tumor phase 2 results of the ADVL1312 trial combining irinotecan and adavosertib.

Methods

Pediatric patients with recurrent neuroblastoma (part B), medulloblastoma/central nervous system embryonal tumors (part C), or rhabdomyosarcoma (part D) were treated with irinotecan and adavosertib orally for 5 days every 21 days. The combination was considered effective if there were at least three of 20 responses in parts B and D or six of 19 responses in part C. Tumor tissue was analyzed for alternative lengthening of telomeres and ATRX. Patient's prior tumor genomic analyses were provided.

Results

The 20 patients with neuroblastoma (part B) had a median of three prior regimens and 95% had a history of prior irinotecan. There were three objective responses (9, 11, and 18 cycles) meeting the protocol defined efficacy end point. Two of the three patients with objective responses had tumors with alternative lengthening of telomeres. One patient with pineoblastoma had a partial response (11 cycles), but parts C and D did not meet the protocol defined efficacy end point. The combination was well tolerated and there were no dose limiting toxicities at cycle 1 or beyond in any parts of ADVL1312 at the recommended phase 2 dose.

Conclusion

This is first phase 2 clinical trial of adavosertib in pediatrics and the first with irinotecan. The combination may be of sufficient activity to consider further study of adavosertib in neuroblastoma.     

Phase I, dose-escalation study of AZD7762 alone and in combination with gemcitabine in Japanese patients with advanced solid tumours

Purpose

AZD7762, a potent Chk1/Chk2 inhibitor, has shown chemosensitizing activity with gemcitabine in xenograft models.

Methods

This open-label, Phase I, dose-escalation study evaluated the safety, pharmacokinetics (PK) and preliminary efficacy (RECIST) of AZD7762 alone and in combination with gemcitabine in Japanese patients with advanced solid tumours (NCT00937664). Patients received intravenous AZD7762 alone on days 1 and 8 of a 14-day cycle (cycle 0), followed by AZD7762 plus gemcitabine 1,000 mg/m² on days 1 and 8 of 22-day cycles, in ascending AZD7762 dose cohorts.

Results

Twenty patients received AZD7762 at doses of 6 mg (n = 3), 9 mg (n = 3), 21 mg (n = 6) and 30 mg (n = 8). Dose-limiting toxicities occurred in 2/6 evaluable patients in the 30-mg cohort: one, CTCAE grade 3 elevated troponin T (cycle 0: AZD7762 monotherapy); one, neutropenia, thrombocytopenia, and elevated aspartate aminotransferase and alanine aminotransferase (cycle 1: combination therapy). The 30 mg dose was therefore regarded as non-tolerable. The most common adverse events (AEs) in cycle 0 (AZD7762 monotherapy) were bradycardia (50 %), hypertension (25 %) and fatigue (15 %). Overall, the most common AEs were bradycardia (55 %), neutropenia (45 %) and hypertension, fatigue and rash (30 % each). Grade ≥3 AEs were reported in 11 patients, the most common being neutropenia (45 %) and leukopenia (25 %). AZD7762 exposure increased approximately linearly. Gemcitabine did not appear to affect AZD7762 PK. There were no objective responses; five patients (all lung cancer) had stable disease.

Conclusions

The maximum tolerated dose of AZD7762 in combination with gemcitabine, 1,000 mg/m² was determined as 21 mg in Japanese patients.     

Targeting human medulloblastoma: oncolytic virotherapy with myxoma virus is enhanced by rapamycin

We have shown previously the oncolytic potential of myxoma virus in a murine xenograft model of human glioma. Here, we show that myxoma virus used alone or in combination with rapamycin is effective and safe when used in experimental models of medulloblastoma in vitro and in vivo. Nine of 10 medulloblastoma cell lines tested were susceptible to lethal myxoma virus infection, and pretreatment of cells with rapamycin increased the extent of in vitro oncolysis. Intratumoral injection of live myxoma virus when compared with control inactivated virus prolonged survival in D341 and Daoy orthotopic human medulloblastoma xenograft mouse models [D341 median survival: 21 versus 12.5 days; P = 0.0008; Daoy median survival: not reached (three of five mice apparently "cured" after 223 days) versus 75 days; P = 0.0021]. Rapamycin increased the extent of viral oncolysis, "curing" most Daoy tumor-bearing mice and reducing or eliminating spinal cord and ventricle metastases. Rapamycin enhanced tumor-specific myxoma virus replication in vivo and prolonged survival of D341 tumor-bearing mice (median survival of mice treated with live virus (LV) and rapamycin, versus LV alone, versus rapamycin alone, versus inactivated virus: 25 days versus 19, 13, and 11 days, respectively; P < 0.0001). Rapamycin increased the levels of constitutively activated Akt in Daoy and D341 cells, which may explain its ability to enhance myxoma virus oncolysis. These observations suggest that myxoma virus may be an effective oncolytic agent against medulloblastoma and that combination therapy with signaling inhibitors that modulate activity of the phosphatidylinositol 3-kinase/Akt pathway will further enhance the oncolytic potential of myxoma virus.     

Robust infectivity and replication of Delta-24 adenovirus induce cell death in human medulloblastoma

The diverse advanced treatment modalities currently available to children with medulloblastoma, including surgery and radiotherapy, are associated with deleterious side effects and often with an unfavorable prognosis. A mutant adenovirus, Delta-24, which has a 24-base pair deletion in the Rb-binding region of the E1A gene, demonstrates selective replication and oncolysis in various malignant phenotypes. Here we report the ability of Delta-24 to kill medulloblastoma cells. Flow cytometric analyses of cell receptors demonstrated expression of the coxsackie adenovirus receptor and RGD-related integrins in the assessed medulloblastoma cell lines. Infectivity assays using a replication-deficient adenovirus to transduce the green fluorescence protein gene showed that the Delta-24 adenovirus infects 99% of Daoy and 46% of D283 Med medulloblastoma cells at a multiplicity of infection (MOI) of 50. Within 4 days after infecting medulloblastoma cells with Delta-24, a noticeable cytopathic effect was produced. Delta-24 induced a total cytopathic effect in Daoy and D283 Med medulloblastoma cells after 6 and 8 days of infection, respectively. In the infected population of cells, cell death correlated with the accumulation of cells in the S phase. At 5 days post-infection with 2.5 MOIs of Delta-24 adenovirus, the percentage of Daoy medulloblastoma cells in the S phase increased to 71.9+/-5.5%, compared with control values of 20.5+/-1.4%. The release of viral progeny was quantified as being increased by two orders of magnitude, indicating efficient replication of Delta-24 in medulloblastoma cells. This is the first report of the ability of oncolytic adenoviruses to infect and kill medulloblastoma cells, the findings of which suggest the potential efficacy of Delta-24 as a therapy for human medulloblastoma tumors.     

Phase I dose-escalation study of AZD7762, a checkpoint kinase inhibitor,in combination with gemcitabine in US patients with advanced solid tumors

Purpose

AZD7762 is a Chk1 kinase inhibitor which increases sensitivity to DNA-damaging agents, including gemcitabine. We evaluated the safety of AZD7762 monotherapy and with gemcitabine in advanced solid tumor patients.

Experimental design

In this Phase I study, patients received intravenous AZD7762 on days 1 and 8 of a 14-day run-in cycle (cycle 0; AZD7762 monotherapy), followed by AZD7762 plus gemcitabine 750–1,000 mg/m² on days 1 and 8, every 21 days, in ascending AZD7762 doses (cycle 1; combination therapy).

Results

Forty-two patients received AZD7762 6 mg (n = 9), 9 mg (n = 3), 14 mg (n = 6), 21 mg (n = 3), 30 mg (n = 7), 32 mg (n = 6), and 40 mg (n = 8), in combination with gemcitabine. Common adverse events (AEs) were fatigue [41 % (17/42) patients], neutropenia/leukopenia [36 % (15/42) patients], anemia/Hb decrease [29 % (12/42) patients] and nausea, pyrexia and alanine aminotransferase/aspartate aminotransferase increase [26 % (11/42) patients each]. Grade ≥3 AEs occurred in 19 and 52 % of patients in cycles 0 and 1, respectively. Cardiac dose-limiting toxicities occurred in two patients (both AZD7762 monotherapy): grade 3 troponin I increase (32 mg) and grade 3 myocardial ischemia with chest pain, electrocardiogram changes, decreased left ventricular ejection fraction, and increased troponin I (40 mg). AZD7762 exposure increased linearly. Gemcitabine did not affect AZD7762 pharmacokinetics. Two non-small-cell lung cancer patients achieved partial tumor responses (AZD7762 6 mg/gemcitabine 750 mg/m² and AZD7762 9 mg cohort).

Conclusions

The maximum-tolerated dose of AZD7762 in combination with gemcitabine 1,000 mg/m² was 30 mg. Although development of AZD7762 is not going forward owing to unpredictable cardiac toxicity, Chk1 remains an important therapeutic target.     

DNA replication stress and cancer chemotherapy

DNA replication is one of the fundamental biological processes in which dysregulation can cause genome instability. This instability is one of the hallmarks of cancer and confers genetic diversity during tumorigenesis. Numerous experimental and clinical studies have indicated that most tumors have experienced and overcome the stresses caused by the perturbation of DNA replication, which is also referred to as DNA replication stress (DRS). When we consider therapeutic approaches for tumors, it is important to exploit the differences in DRS between tumor and normal cells. In this review, we introduce the current understanding of DRS in tumors and discuss the underlying mechanism of cancer therapy from the aspect of DRS.     

Targeting ER stress induced apoptosis and inflammation in cancer

Disturbance in the folding capacity of the endoplasmic reticulum (ER), caused by a variety of endogenous and exogenous insults, prompts a cellular stress condition known as ER stress. ER stress is initially shaped to re-establish ER homeostasis through the activation of an integrated intracellular signal transduction pathway termed as unfolded protein response (UPR). However, when ER stress is too severe or prolonged, the pro-survival function of the UPR turns into a toxic signal, which is predominantly executed by mitochondrial apoptosis. Moreover, accumulating evidence implicates ER stress pathways in the activation of various ‘classical’ inflammatory processes in and around the tumour microenvironment. In fact, ER stress pathways evoked by certain conventional or experimental anticancer modalities have been found to promote anti-tumour immunity by enhancing immunogenicity of dying cancer cells. Thus, the ER functions as an essential sensing organelle capable of coordinating stress pathways crucially involved in maintaining the cross-talk between the cancer cell’s intracellular and extracellular environment. In this review we discuss the emerging link between ER stress, cell fate decisions and immunomodulation and the potential therapeutic benefit of targeting this multifaceted signaling pathway in anticancer therapy.     

Targeting endoplasmic reticulum stress signaling in ovarian cancer therapy

The endoplasmic reticulum(ER), an organelle present in various eukaryotic cells, is responsible for intracellular protein synthesis, post-translational modification, and folding and transport, as well as the regulation of lipid and steroid metabolism and Ca²⁺ homeostasis. Hypoxia, nutrient deficiency, and a low pH tumor microenvironment lead to the accumulation of misfolded or unfolded proteins in the ER, thus activating ER stress(ERS) and the unfolded protein response, and resulting ...     

mTORC2 regulates ribonucleotide reductase to promote DNA replication and gemcitabine resistance in non-small cell lung cancer

Ribonucleotide reductase (RNR) is the key enzyme that catalyzes the production of deoxyribonucleotides (dNTPs) for DNA replication and it is also essential for cancer cell proliferation. As the RNR inhibitor, Gemcitabine is widely used in cancer therapies, however, resistance limits its therapeutic efficacy and curative potential. Here, we identified that mTORC2 is a main driver of gemcitabine resistance in non-small cell lung cancers (NSCLC). Pharmacological or genetic inhibition of mTORC2 greatly enhanced gemcitabine induced cytotoxicity and DNA damage. Mechanistically, mTORC2 directly interacted and phosphorylated RNR large subunit RRM1 at Ser 631. Ser631 phosphorylation of RRM1 enhanced its interaction with small subunit RRM2 to maintain sufficient RNR enzymatic activity for efficient DNA replication. Targeting mTORC2 retarded DNA replication fork progression and improved therapeutic efficacy of gemcitabine in NSCLC xenograft model in vivo. Thus, these results identified a mechanism through mTORC2 regulating RNR activity and DNA replication, conferring gemcitabine resistance to cancer cells.     

Distinct RAD51 associations with RAD52 and BCCIP in response to DNA damage and replication stress

RAD51 has critical roles in homologous recombination (HR) repair of DNA double-strand breaks (DSB) and restarting stalled or collapsed replication forks. In yeast, Rad51 function is facilitated by Rad52 and other "mediators." Mammalian cells express RAD52, but BRCA2 may have supplanted RAD52 in mediating RAD51 loading onto ssDNA. BCCIP interacts with BRCA2, and both proteins are important for RAD51 focus formation after ionizing radiation and HR repair of DSBs. Nonetheless, mammalian RAD52 shares biochemical activities with yeast Rad52, including RAD51 binding and single-strand annealing, suggesting a conserved role in HR. Because RAD52 and RAD51 associate, and RAD51 and BCCIP associate, we investigated the colocalization of RAD51 with BCCIP and RAD52 in human cells. We found that RAD51 colocalizes with BCCIP early after ionizing radiation, with RAD52 later, and there was little colocalization of BCCIP and RAD52. RAD52 foci are induced to a greater extent by hydroxyurea, which stalls replication forks, than by ionizing radiation. Using fluorescence recovery after photo bleaching, we show that RAD52 mobility is reduced to a greater extent by hydroxyurea than ionizing radiation. However, BCCIP showed no changes in mobility after hydroxyurea or ionizing radiation. We propose that BCCIP-dependent repair of DSBs by HR is an early RAD51 response to ionizing radiation-induced DNA damage, and that RAD52-dependent HR occurs later to restart a subset of blocked or collapsed replication forks. RAD52 and BRCA2 seem to act in parallel pathways, suggesting that targeting RAD52 in BRCA2-deficient tumors may be effective in treating these tumors.     

Genetic alterations in glioma and medulloblastoma

Multiple genetic changes take place during tumor development and progression. These genetic changes result in inactivation of tumor suppressor genes and activation of proto-oncogenes. Frequent genetic changes observed in gliomas are losses of chromosomal regions on 9p, 10q, 13q, 17p and on 22. Loss of 10q is seen in more than 80% of the glioblastoma multiforme (GBM) tumors suggesting the presence of a gene critical for GBM formation on this chromosome. Amplification of epidermal growth factor receptor gene and expression of platelet derived growth factor and fibroblast growth factor genes are also common among gliomas. The most common genetic abnormality found in medulloblastomas is loss of 17p. The C-myc gene is amplified in a few primary tumors, but the incidence of amplification is higher in medulloblastoma derived cell lines. These findings suggest that the same two genetic processes, gene amplification and regional chromosomal loss, which characterize other primitive childhood neuroectodermal tumors such as retinoblastoma and neuroblastoma are also important in medulloblastomas.     

Cisplatin and gemcitabine in patients with metastatic cervical cancer

PURPOSE: To determine the therapeutic efficacy of cisplatin plus gemcitabine in the treatment of patients with metastatic cervical cancer. METHODS AND MATERIALS: A total of 51 patients were enrolled in this study. The median age was 46 years (34-67). Thirty-five patients were previously treated to the pelvis by radical radiotherapy, one patient was treated by surgery and one by surgery and postoperative radiotherapy. There were 14 patients with stage IVB cervical cancer who were previously untreated. The sites of metastases were 10 in the lungs, 5 in the supraclavicular nodes, 9 in the paraaortic nodes, 4 in the liver, 3 in the inguinal nodes, 5 in both supraclavicular nodes and lungs, 9 in both supraclavicular and paraaortic nodes, 1 in both supraclavicular and inguinal nodes, 1 in both lung and inguinal nodes, 2 in both lung and paraaortic nodes and 2 in both liver and lungs. Fine needle biopsies were done in all metastatic sites except for multiple lung and multiple liver metastases. Cisplatin was administered as an i.v. infusion on day 1 (70 mg/m2). Gemcitabine was administered as an i.v. infusion for over 30 minutes on day 1 and 8 (1,250 mg/m2) in a 21 day cycle. RESULTS: Forty patients were available for evaluation, with 3/40 (7.5%) achieving a complete response, 27/40 (67.5%) achieving a partial response (OR=30/40, 75%), 5/40 (12.5%) having a stable disease, and 5/40 (12.5%) a progressive one. Eleven patients were not assessable because of patient refusal for further treatment and loss of follow up. Myelosuppression was the major toxicity. Grade 3 or 4 anemia and granulocytopenia occurred at a frequency of 25.5% and 29.4%, respectively. Grade 3-4 thrombocytopenia was found in 3.8%. There were 3 (5.8%) patients who developed grade 4 neutropenia and fever. No other major side effects were found other than alopecia and usual gastrointestinal toxicities such as anorexia, nausea and vomiting. There were no treatment related deaths. The median time to progression was 8.3 months and the median survival was 9.6 months. With a median follow up of 7.7 months (range, 0.3 to 22.1), 30% of the patients were alive at 12 months. CONCLUSION: In this study of patients with metastatic cervical cancer, the combination of cisplatin and gemcitabine treatment induced a high response rate.