Pharmacokinetic comparison of oral and intravenous etoposide in patients treated with the CHOEP-regimen for malignant lymphomas

Non-chemotherapy adjuvant agents in TP53 mutant Ewing sarcoma

Ewing sarcoma (EWS) is a malignant tumor arising in bone or soft tissue that occurs in adolescent and young adult patients as well as adults later in life. Although non-metastatic EWS is typically responsive to treatment when newly diagnosed, relapsed cases have an unmet need for which no standard treatment approach exists. Recent phase III clinical trials for EWS comparing 7 vs 5 chemotherapy drugs have failed to improve survival. To extend the durability of remission for EWS, we investigated 3 non-chemotherapy adjuvant therapy drug candidates to be combined with chemotherapy. The efficacy of these adjuvant drugs was investigated via anchorage-dependent growth assays, anchorage-independent soft-agar colony formation assays and EWS xenograft mouse models. Enoxacin and entinostat were the most effective adjuvant drug in both long-term in vitro and in vivo adjuvant studies. In the context that enoxacin is an FDA-approved antibiotic, and that entinostat is an investigational agent not yet FDA-approved, we propose enoxacin as an adjuvant drug for further preclinical and clinical investigation in EWS patients.

Carboplatin in Combination with Oral or Intravenous Etoposide for Extra-Pulmonary, Poorly-Differentiated Neuroendocrine Carcinomas

BACKGROUND

Carboplatin-etoposide (CarboEtop) is a 1st-line option for patients with advanced extra-pulmonary (EP), poorly-differentiated (PD) neuroendocrine carcinoma (NEC). Different schedules are used in clinical practice and randomised evidence is lacking.

OBJECTIVES

To provide real-life outcomes of carboplatin combined with oral or intravenous (IV) etoposide (Etop) in advanced EP-PD-NEC, from 2 specialist centres.

METHODS

Activity/efficacy/toxicity data of CarboEtop were collected retrospectively and analysed.

RESULTS

We identified 113 patients; median age: 65.8 years; male: 64%; gastro-entero-pancreatic origin: 54%; stage IV: 90%; median Ki-67: 70%; median follow-up: 11.5 months. A total of 123 courses of CarboEtop (oral: 45%; IV: 55%) were administered; 106 (86%) 1st-line, 16 (13%) 2nd-line, and 1 (1%) 3rd-line. Disease control rate: 74.5% in 1st-line and 69.2% in 2nd/3rd-line, with no significant difference between oral and IV Etop in 1st-line (69.8 vs. 80.8%, p = 0.237). Median progression-free survival (PFS): 6.0 and 4.5 months in 1st-line and 2nd/3rd-line, respectively. Overall survival (OS): 11.5 and 12.5 months in 1st-line and 2nd/3rd-line, respectively. The schedule (oral versus IV Etop) did not impact on 1st-line PFS (5.6 vs. 6.2 months, p = 0.179), although there was a trend towards shorter OS (8.9 vs. 12.1 months, p = 0.069). Liver metastases correlated with worse 1st-line PFS (p = 0.015) and 1st-line OS (p < 0.001) on multivariable analysis. The commonest grade 3-4 adverse event was myelosuppression (49%), with comparable toxicity between oral and IV Etop, except for venous thromboembolism (12.5 vs. 1.7%, p = 0.04).

CONCLUSIONS

CarboEtop for advanced EP-PD-NEC is active, effective, and well-tolerated. Oral and IV Etop schedules are associated with comparable toxicity; activity should be compared in larger cohorts.

A quasi-quantitative dual multiplexed immunoblot method to simultaneously analyze ATM and H2AX Phosphorylation in human peripheral blood mononuclear cells

Pharmacologic inhibition of DNA repair may increase the efficacy of many cytotoxic cancer agents. Inhibitors of DNA repair enzymes including APE1, ATM, ATR, DNA-PK and PARP have been developed and the PARP inhibitor olaparib is the first-in-class approved in Europe and the USA for the treatment of advanced BRCA-mutated ovarian cancer. Sensitive pharmacodynamic (PD) biomarkers are needed to further evaluate the efficacy of inhibitors of DNA repair enzymes in clinical trials. ATM is a protein kinase that mediates cell-cycle checkpoint activation and DNA double-strand break repair. ATM kinase activation at DNA double-strand breaks (DSBs) is associated with intermolecular autophosphorylation on serine-1981. Exquisite sensitivity and high stoichiometry as well as facile extraction suggest that ATM serine-1981 phosphorylation may be a highly dynamic PD biomarker for both ATM kinase inhibitors and radiation- and chemotherapy-induced DSBs. Here we report the pre-clinical analytical validation and fit-for-purpose biomarker method validation of a quasi-quantitative dual multiplexed immunoblot method to simultaneously analyze ATM and H2AX phosphorylation in human peripheral blood mononuclear cells (PBMCs). We explore the dynamics of these phosphorylations in PBMCs exposed to chemotherapeutic agents and DNA repair inhibitors in vitro, and show that ATM serine-1981 phosphorylation is increased in PBMCs in sarcoma patients treated with DNA damaging chemotherapy.

Inhibition of Bcl-2 or IAP proteins does not provoke mutations in surviving cells

Chemotherapy and radiotherapy can cause permanent damage to the genomes of surviving cells, provoking severe side effects such as second malignancies in some cancer survivors. Drugs that mimic the activity of death ligands, or antagonise pro-survival proteins of the Bcl-2 or IAP families have yielded encouraging results in animal experiments and early phase clinical trials. Because these agents directly engage apoptosis pathways, rather than damaging DNA to indirectly provoke tumour cell death, we reasoned that they may offer another important advantage over conventional therapies: minimisation or elimination of side effects such as second cancers that result from mutation of surviving normal cells. Disappointingly, however, we previously found that concentrations of death receptor agonists like TRAIL that would be present in vivo in clinical settings provoked DNA damage in surviving cells. In this study, we used cell line model systems to investigate the mutagenic capacity of drugs from two other classes of direct apoptosis-inducing agents: the BH3-mimetic ABT-737 and the IAP antagonists LCL161 and AT-406. Encouragingly, our data suggest that IAP antagonists possess negligible genotoxic activity. Doses of ABT-737 that were required to damage DNA stimulated Bax/Bak-independent signalling and exceeded concentrations detected in the plasma of animals treated with this drug. These findings provide hope that cancer patients treated by BH3-mimetics or IAP antagonists may avoid mutation-related illnesses that afflict some cancer survivors treated with conventional DNA-damaging anti-cancer therapies.

Inhibition of OCTN2-mediated transport of carnitine by etoposide

OCTN2 is a bifunctional transporter that reabsorbs filtered carnitine in a sodium-dependent manner and secretes organic cations into urine as a proton antiport mechanism. We hypothesized that inhibition of OCTN2 by anticancer drugs can influence carnitine resorption. OCTN2-mediated transport inhibition by anticancer drugs was assessed using cells transfected with human OCTN2 (hOCTN2) or mouse Octn2 (mOctn2). Excretion of carnitine and acetylcarnitine was measured in urine collected from mice and pediatric patients with cancer before and after administration of etoposide. Five of 27 tested drugs (50-100 μmol/L) inhibited hOCTN2-mediated carnitine uptake by 42% to 85% (P < 0.001). Of these inhibitors, etoposide was itself a transported substrate of hOCTN2 and mOctn2. Etoposide uptake by hOCTN2 was reversed in the presence of excess carnitine. This competitive inhibitory mechanism was confirmed in an in silico molecular docking analysis. In addition, etoposide inhibited the transcellular apical-to-basolateral flux of carnitine in kidney cells. Etoposide was also associated with a significant urinary loss of carnitine in mice (~1.5-fold) and in patients with cancer (~2.4-fold). Collectively, these findings indicate that etoposide can inhibit hOCTN2 function, potentially disturb carnitine homeostasis, and that this phenomenon can contribute to treatment-related toxicities.

Irinotecan Plus Carboplatin Versus Oral Etoposide Plus Carboplatin in Extensive Small-Cell Lung Cancer: A Randomized Phase III Trial

Purpose

A Japanese randomized trial showed superior survival for patients with extensive-disease (ED) small-cell lung cancer (SCLC) receiving irinotecan plus cisplatin compared with etoposide plus cisplatin. The present trial evaluated the efficacy of irinotecan plus carboplatin (IC) compared with oral etoposide plus carboplatin (EC).

Patients and Methods

Patients with ED SCLC were randomly assigned to receive either IC, which consisted of carboplatin (area under the curve = 4; Chatelut formula) and irinotecan (175 mg/m2) intravenously both on day 1, or EC, which consisted of carboplatin as in IC and etoposide (120 mg/m2/d) orally on days 1 through 5. Courses were repeated every 3 weeks with four cycles planned. Doses were reduced by one third in patients with a WHO performance status (PS) of 3 to 4 and/or age older than 70 years. Primary end point was overall survival (OS). Secondary end points were quality of life (QOL) and complete response (CR) rate.

Results

Of 220 randomly assigned patients, 209 were eligible for analysis (IC, n = 105; EC, n = 104). Thirty-five percent were older than 70 years, and 47% had a PS of 2 to 4. The groups were well balanced with respect to prognostic factors. OS was inferior in the EC group (hazard ratio = 1.41; 95% CI, 1.06 to 1.87; P = .02). Median survival time was 8.5 months for IC compared with 7.1 months for EC. One-year survival rate was 34% for IC and 24% for EC. CR was seen in 18 IC patients compared with seven EC patients (P = .02). There were no statistically significant differences in hematologic grade 3 or 4 toxicity. Grade 3 or 4 diarrhea was more common in the IC group. QOL differences were small, with a trend toward prolonged palliation with the IC regimen.

Conclusion

IC prolongs survival in ED SCLC with slightly better scores for QOL.