The role of dacarbazine and temozolomide therapy after treatment with immune checkpoint inhibitors in malignant melanoma patients: A case series and meta-analysis

Dacarbazine (DTIC) and its oral counterpart temozolomide (TMZ) have been the most used agents in advanced malignant melanoma (MM) patients and they are still used routinely. The preferred first line treatment, immune checkpoint inhibitors (CPIs) might shape the tumor and the tumor microenvironment, possibly affecting the response to subsequent therapies. The aim of this study was to investigate the treatment effect of DTIC/TMZ in MM patients after CPI therapy in a consecutive patient cohort and through systematic literature review and meta-analysis. Thirty-five patients with advanced MM treated with DTIC/TMZ after previous CPI therapy in three Swedish regions between 2017 and 2021 were recognized and seven case series studies were identified through systematic database review. Pooled data from all 345 patients showed a median real-world progression-free survival (rwPFS) of 1.9 months and overall survival (OS) of 6.0 months. Three of these studies were included in a meta-analysis comparing DTIC/TMZ after CPI treatment, versus no previous immunotherapy, showing no statistically significant differences in rwPFS or OS but higher real-world response rate to chemotherapy for the prior-CPI treated group (Odds Ratio: 2.24; 95% Confidence Interval: 1.04-4.86). The current study supports consideration of DTIC/TMZ in later line of treatment in the immunotherapy era.

Fabrication of Bacterial Cellulose/Chitosan-MIL-100(Fe) Composite for Adsorptive Removal of Dacarbazine

In this research, a polymeric composite based on a chitosan/bacterial cellulose (CS/BC) matrix filled with MIL-100(Fe) particles was prepared to solve the recyclability of issue MIL-100(Fe) particles and utilized as an efficient adsorbent for removing dacarbazine (DTIC) from wastewater. The adsorption capacity of the composite (CS/BC-MIL) was higher than both MIL-100(Fe) and the CS/BC polymeric matrix. The adsorption performance of the fabricated composite was evaluated through kinetics and isotherm studies. While isotherm studies revealed that the adsorption of DTIC onto the adsorbent can be well described by the Freundlich model, kinetics studies indicated that a combination of factors, rather than a single rate-limiting factor, are responsible for the adsorption rate. Thermodynamics investigation showed that the adsorption of DTIC to CS/BC-MIL composite is exothermic and occurs spontaneously. Additionally, due to the negative entropy change, it was established that the adsorption is governed by the enthalpy change. Exploring the solution chemistry revealed that the optimum pH for the adsorption process was about 4. Moreover, the CS/BC-MIL can selectively adsorb DTIC in the presence of other pharmaceuticals like doxorubicin (DOX). Furthermore, regeneration investigations disclosed that the composite holds its structural features and has an acceptable adsorption capacity after several cycles of adsorption/desorption.

Core-Shell Reactor Partitioning Enzyme and Prodrug by ZIF-8 for NADPH-Sensitive In Situ Prodrug Activation

Enzyme-prodrug therapies have shown unique advantages in efficiency, selectivity, and specificity of in vivo prodrug activation. However, precise spatiotemporal control of both the enzyme and its substrate at the target site, preservation of enzyme activity, and in situ substrate depletion due to low prodrug delivery efficiency continue to be great challenges. Here, we propose a novel core-shell reactor partitioning enzyme and prodrug by ZIF-8, which integrates an enzyme with its substrate and increases the drug loading capacity (DLC) using a prodrug as the building ligand to form a Zn-prodrug shell. Cytochrome P450 (CYP450) is immobilized in ZIF-8, and the antitumor drug dacarbazine (DTIC) is coordinated and deposited in its outer layer with a high DLC of 43.6±0.8 %. With this configuration, a much higher prodrug conversion efficiency of CYP450 (36.5±1.5 %) and lower IC50 value (26.3±2.6 μg/mL) are measured for B16-F10 cells with a higher NADPH concentration than those of L02 cells and HUVECs. With the tumor targeting ability of hyaluronic acid, this core-shell enzyme reactor shows a high tumor suppression rate of 96.6±1.9 % and provides a simple and versatile strategy for enabling in vivo biocatalysis to be more efficient, selective, and safer.

Preparation of chitosan nanoparticles for simultaneous drug delivery of dacarbazine and enoxaparin in melanoma

The aim of this study was to investigate the anti-melanoma and anti-angiogenic effects of enoxaparin surface-coated dacarbazine-loaded chitosan nanoparticles (Enox-Dac-Chi NPs). The prepared Enox-Dac-Chi NPs had a particle size of 367.95 ± 1.84 nm, zeta potential of -7.12 ± 0.25 mV, efficiency of drug loading (DL%) of 73.90 ± 3.84 %, and attached enoxaparin percentage of 98.53 ± 0.96 %. Both drugs had extended-release profiles and approximately 96 % of enoxaparin and 67 % dacarbazine were released within 8 h. The Enox-Dac-Chi NPs with IC₅₀ of 59.60 ± 1.25 μg/ml were the most cytotoxic against melanoma cancer cells compared with chitosan nanoparticles containing only dacarbazine (Dac-Chi NPs) and free dacarbazine. There was no significant difference between the cellular uptake of Chi NPs and enoxaparin coated Chi NPs (Enox-Chi NPs) in B16F10 cells. Enox-Chi NPs with an average anti-angiogenic score of 1.75 ± 0.125 had more anti-angiogenic effect than enoxaparin. The results showed that simultaneous delivery of dacarbazine and enoxaparin by chitosan nanoparticles can enhance the anti-melanoma effect of dacarbazine. Additionally, enoxaparin can prevent the melanoma metastasis by its anti-angiogenic activity. Thus, the designed nanoparticles can be introduced as effective drug delivery vehicles for the treatment and prevention of metastatic melanoma.

The effect of sulindac on redox homeostasis and apoptosis-related proteins in melanotic and amelanotic cells

BACKGROUND

Non-steroidal anti-inflammatory drugs have been shown to inhibit the development of induced neoplasms. Our previous research demonstrated that the cytotoxicity of sulindac against melanoma cells is comparable to dacarbazine, the drug used in chemotherapy. The aim of this study was to investigate the mechanism of sulindac cytotoxicity on COLO 829 and C32 cell lines.

METHODS

The influence of sundilac on the activity of selected enzymes of the antioxidant system (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)) and the content of hydrogen peroxide as well as the level of proteins initiating (p53, Bax) and inhibiting (Bcl-2) apoptosis were measured in melanoma cells.

RESULTS

In melanotic melanoma cells, sulindac increased the activity of SOD and the content of H2O2 but decreased the activity of CAT and GPx. The level of p53 and Bax proteins rose but the content of Bcl-2 protein was lowered. Similar results were observed for dacarbazine. In amelanotic melanoma cells, sulindac did not cause an increase in the activity of measured enzymes or any significant changes in the level of apoptotic proteins.

CONCLUSION

The cytotoxic effect of sulindac in the COLO 829 cell line is connected to disturbed redox homeostasis by changing the activity of SOD, CAT, GPx, and level of H2O2. Sulindac also induces apoptosis by changing the ratio of the pro-apoptotic/anti-apoptotic protein. The presented studies indicate the possibility of developing target therapy against melanotic melanoma using sulindac.

Morusinol extracted from Morus alba induces cell cycle arrest and apoptosis via inhibition of DNA damage response in melanoma by CHK1 degradation through the ubiquitin-proteasome pathway

BACKGROUD

Flavonoids have a variety of biological activities, such as anti-inflammation, anti-tumor, anti-thrombosis and so on. Morusinol, as a novel isoprene flavonoid extracted from Morus alba root barks, has the effects of anti-arterial thrombosis and anti-inflammatory in previous studies. However, the anti-cancer mechanism of morusinol remains unclear.

PURPOSE

In present study, we mainly studied the anti-tumor effect of morusinol and its mode of action in melanoma.

METHODS

The anti-cancer effect of morusinol on melanoma were evaluated by using the MTT, EdU, plate clone formation and soft agar assay. Flow cytometry was used for detecting cell cycle and apoptosis. The ɣ-H2AX immunofluorescence and the alkaline comet assay were used to detect DNA damage and the Western blotting analysis was used to investigate the expressions of DNA-damage related proteins. Ubiquitination and turnover of CHK1 were also detected by using the immunoprecipitation assay. The cell line-derived xenograft (CDX) mouse models were used in vivo to evaluate the effect of morusinol on tumorigenicity.

RESULTS

We demonstrated that morusinol not only had the ability to inhibit cell proliferation, but also induced cell cycle arrest at G0/G1 phase, caspase-dependent apoptosis and DNA damage in human melanoma cells. In addition, morusinol effectively inhibited the growth of melanoma xenografts in vivo. More strikingly, CHK1, which played an important role in maintaining the integrity of cell cycle, genomic stability and cell viability, was down-regulated in a dose- and time-dependent manner after morusinol treatment. Further research showed that CHK1 was degraded by the ubiquitin-proteasome pathway. Whereafter, morusinol-induced cell cycle arrest, apoptosis and DNA damage were partially salvaged by overexpressing CHK1 in melanoma cell lines. Herein, further experiments demonstrated that morusinol increased the sensitivity of dacarbazine (DTIC) to chemotherapy for melanoma in vitro and in vivo.

CONCLUSION

Morusinol induces CHK1 degradation through the ubiquitin-proteasome pathway, thereby inducing cell cycle arrest, apoptosis and DNA damage response in melanoma. Our study firstly provided a theoretical basis for morusinol to be a candidate drug for clinical treatment of cancer, such as melanoma, alone or combinated with dacarbazine.

Protocatechuic aldehyde acts synergistically with dacarbazine to augment DNA double-strand breaks and promote apoptosis in cutaneous melanoma cells

BACKGROUND

Despite rapid developments in immunotherapy and targeted therapy, dacarbazine (DTIC)-based chemotherapy still has been placed at the first-line for advanced melanoma patients who are after failure of immunotherapy or targeted therapy. However, the limited response rate and survival benefit challenge the DTIC-based chemotherapy for advanced melanoma patients.

METHODS

Two melanoma cell lines, A375 and SK-MEL-28 were cultured with PA and DTIC over a range of concentrations for 72 h and the cell viabilities were detected by CCK8 assay. The Bliss model and ZIP model were used for calculating the synergistic effect of PA and DTIC. DNA double-strand breaks in the two cell lines were examined by the Comet assay, and cell apoptosis was analyzed by flow cytometry. The short hairpin RNA (shRNA)-mediated knockdown, Real-time polymerase chain reaction (RT-PCR) and Western blot were performed for molecular analysis.

RESULTS

In the present study, we report that Protocatechuic aldehyde (PA) synergistically enhances the cytotoxicity of DTIC to two melanoma cell lines, A375 and SK-MEL-28. The combination of PA and DTIC augments DNA double-strand breaks and increases cell apoptosis. Further mechanism study reveals that PA destabilizes MGMT protein (O-6-Methylguanine-DNA Methyltransferase) through the ubiquitin-proteasome process and directly repairs DTIC-induced genetic lesions. Knockdown of MGMT compromises the synergistic effect between PA and DTIC.

CONCLUSION

Our study demonstrates that the bioactive compound, Protocatechuic aldehyde, synergistically promotes the cytotoxicity of DTIC to melanoma cells through destabilization of MGMT protein. It could be a potential candidate for melanoma chemotherapy.

Sonodynamic Therapy Using Dacarbazine-Loaded AuSiO2 Nanoparticles for Melanoma Treatment: An In-Vitro Study on the B16F10 Murine Melanoma Cell Line

The use of nanoparticles as a sonosensitizer in cancer sonodynamic therapy has been gaining attention because of their great advantages in drug delivery applications. By conjugating chemotherapy agents with nanoparticles, we can develop a drug delivery platform, control drug release and improve the outcome of treatments. The in-vitro study described here evaluates the combination of AuSiO₂ nanoparticles and dacarbazine (DTIC@AuSiO₂) as a sonosensitizer for sonodynamic therapy of melanoma. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays revealed that the viability of B16F10 melanoma cells was significantly inhibited by the increase in apoptosis induction in treatment with DTIC@AuSiO₂ nanoparticles under ultrasound exposure compared with treatment with the free DTIC or AuSiO₂ nanoparticles. The sonosensitization activity of AuSiO₂ nanoparticles and greater uptake of DTIC by tumor cells after loading in DTIC@AuSiO₂ nanoparticles inhibited the proliferation of melanoma tumor cells effectively. In conclusion, the DTIC@AuSiO₂ nanoparticles established in this study could represent a good drug delivery and sonosensitizer platform for use in melanoma sonodynamic therapy.

Green synthesis of PEG-coated MIL-100(Fe) for controlled release of dacarbazine and its anticancer potential against human melanoma cells

In this study, the potential of using MIL-100(Fe) metal-organic framework (MOF) for loading and controlling the release of dacarbazine (DTIC) was evaluated for in vitro treatment of melanoma. The drug loading was performed during the green synthesis of MIL-100(Fe) in an aqueous media without using any harmful solvents, to obtain MIL-DTIC. The surface of this structure was then coated with polyethylene glycol (PEG) in the same aqueous solution to synthesize MIL-DTIC-PEG. The synthesized samples were characterized using various methods. Their release profile was studied in phosphate-buffered saline (PBS) and simulated cutaneous medium (SCM). The cytotoxicity of DTIC and its nano-MOF formulation were investigated against melanoma A375 cell lines. The results revealed that the PEG coating (PEGylation) changed the surface charge of MOF from -2.8 ± 0.9 mV to -42.8 ± 1.2 mV, which can contribute to the colloidal stability of MOF. The PEGylation showed a significant effect on controlled drug release, especially in SCM, which increases the complete release time from 60 h to 12 days. Moreover, both of the drug-containing MOFs showed more toxicity than DTIC and unloaded MOFs, confirming that the cumulative release of drug and better cellular uptake of NPs lead to increased toxicity.

Adsorption properties of dacarbazine with graphene/fullerene/metal nanocages - Reactivity, spectroscopic and SERS analysis

Drug delivery devices are an effective way to minimize anticancer drug toxicity and nanostructures are used in the targeted drug delivery. In the present work, adsorption and interaction behavior of 4-(dimethylaminodiazenyl)-1H-imidazole-5-carboxamide (DAIC) with nano complexes (graphene, fullerene and fullerene like metal cages) are reported theoretically. From the reactivity studies, the electrophilicity index of DAIC-nanoclusters are increasing and this gives the bioactivity of the nanocluster systems. Adsorption energy is highest in the case of AlP and lowest in the case of BP clusters. Mulliken charge distribution of all systems is an evidence for chemical enhancement. DAIC adsorption over nanocages causes changes in electronic properties resulting in chemical enhancement and variation in Raman spectra which suggests that nanocages could be a good candidate for DAIC detection.

Caffeine improves the cytotoxic effect of dacarbazine on B16F10 murine melanoma cells

OBJECTIVE

Caffeine has been studied as a potentiating agent in chemotherapy against some types of cancer, but there are few reports on its effects on melanoma. This study aimed to investigate caffeine's ability to enhance the effects of dacarbazine in vitro.

MATERIALS AND METHODS

Murine melanoma B16F10 cells were treated 24 h with 1-40 µM caffeine. We evaluated cytotoxicity, DNA damage, apoptosis, and oxidative lesion induced by dacarbazine associated with caffeine. The metabolization of these drugs, as well as immunocytochemical labeling, were also evaluated.

CONCLUSIONS

The pre-treatment with caffeine showed to be more effective. Caffeine potentiated dacarbazine-induced cytotoxic effects by increasing dacarbazine biotransformation, apoptosis, DNA damage, and malondialdehyde levels; also, caffeine reduced Ki67 and ERK1/2 nuclear labeling and increased p53 labeling in B16F10 cells. In our experiment, caffeine promoted modifications associated with dacarbazine metabolism by viable cells potentiating this antineoplastic drug. These promising results should be further evaluated in experimental models in vivo.

Ubiquitination and degradation of MGMT by TRIM72 increases the sensitivity of uveal melanoma cells to Dacarbazine treatment

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults with high metastasis rates. The O6-methylguanine DNA methyl transferase (MGMT) is involved in chemoresistance of Dacarbazine (DTIC) treatment. Our previous study found that the combination of oncolytic adenovirus H101 and DTIC in the treatment of UM cells shows a synergistic antitumor effect mainly though down-regulation of MGMT. MGMT knockdown by shRNAs increases the sensitivity of uveal melanoma cells to DTIC treatment. The protein hemostasis of MGMT is important for the antitumor effect of DTIC. Tripartite motif-containing protein 72 (TRIM72) belongs to the tripartite motif (TRIM) proteins family and was identified as a novel E3 ligase for MGMT, which interacts with and mediates the ubiquitination of MGMT. TRIM72 knockdown increases the protein levels of MGMT, while reduces the ubiquitination of MGMT. Further study indicated that MGMT is highly expressed in UM cells, and the protein levels of MGMT and TRIM72 shows a negative correlation. UM cells that ectopically expressing TRIM72 shows increased sensitivity to DTIC treatment, which is consistent with the antitumor affect exhibited by H101. These results suggest that TRIM72 is a promising therapeutic target for UM treatment.

Chemotherapy in focus: A meta-analysis confronts immunotherapy in the treatment of advanced melanoma

This study aimed to analyze the efficacy of the monoclonal antibodies ipilimumab, nivolumab, and pembrolizumab when compared with conventional chemotherapy in the treatment of advanced melanoma. Three authors made the search independently and five articles matched the eligibility criteria. A fourth expert confirmed their quality (κ = 1). The meta-analysis for overall survival and 12-month overall survival was impaired due to remarkably high heterogeneity (I2 = 91 % and 86 %, respectively). However, chemotherapy showed benefits on 24-months overall survival (RR = 1.60; IC95 %: 1.29, 1.98; p < 0.0001). The interruption by toxicity outcome showed no significant differences between therapies. Some studies used monoclonal antibodies in monotherapy or in combination and some groups of participants showed heterogeneity, which made the analysis difficult. Given the exorbitant costs of monoclonal antibodies in low and middle-income countries, the evidence of its benefits is limited when considering the replacement of conventional therapy with immunotherapy in public health systems.

Melatonin and Metformin Failed to Modify the Effect of Dacarbazine in Melanoma

LESSONS LEARNED

Melatonin did not increase the efficacy of systemic chemotherapy in melanoma. Metformin did not increase the efficacy of systemic chemotherapy in melanoma.

BACKGROUND

Current data support the possibility of antitumor activity of melatonin and metformin.

METHODS

From March 2014 to December 2016, 57 patients with disseminated melanoma received dacarbazine (DTIC) 1,000 mg/m² on day 1 of a 28-day cycle, either as monotherapy (first group) or in combination with melatonin 3 mg p.o. daily (second group) or metformin 850 mg two times a day p.o. daily (third group) as the first-line of chemotherapy. The primary endpoint was objective response rate (ORR). Secondary endpoints were time to progression (TTP), overall survival (OS), immunologic biomarkers, and quality of life.

RESULTS

ORR was 7% and did not differ among the treatment groups. Median TTP was 57, 57, and 47 days, respectively, in the first, second, and third groups (р = .362). Median OS was 236, 422, and 419 days, respectively (p = .712). Two patients from the combinations groups showed delayed response to therapy. The increase of CD3⁺ CD4⁺ HLA-DR⁺ lymphocytes (p = .003), CD3⁺ CD8⁺ HLA-DR⁺ (p = .045), CD3⁺ CD8⁺ lymphocytes (p = .012), CD4⁺ CD25^high CD127^low lymphocytes (p = .029), and overall quantity of lymphocytes (p = .021) was observed in patients with clinical benefit.

CONCLUSION

No benefit was found in either combination over DTIC monotherapy. Delayed responses in melatonin and metformin combination groups were registered. The increase of lymphocyte subpopulations responsible for antitumor immune response demonstrates the immune system's potential involvement in clinical activity.

CD47-mediated DTIC-loaded chitosan oligosaccharide-grafted nGO for synergistic chemo-photothermal therapy against malignant melanoma

Nano-graphene oxide (nGO), an effective drug nanocarrier, is used for simultaneous photothermal therapy (PTT) and near-infrared fluorescence imaging. Dacarbazine (DTIC) is used in the treatment of melanoma with limited clinical efficacy. PTT shows promise in the treatment of skin cancer. Herein, chitosan oligosaccharide (COS)-grafted nGO was further modified with CD47 antibody, and loaded DTIC was prepared using a versatile nanoplatform (nGO-COS-CD47/DTIC) for the treatment of melanoma as a synergistic targeted chemo-photothermal therapy. The in vitro results demonstrated that nGO-COS-CD47/DTIC nanocarriers have excellent biocompatibility, photothermal conversion efficiency, high targeting efficiency, fast drug release under NIR irradiation, and tumor cell killing efficiency. Notably, nGO-COS-CD47/DTIC plus NIR irradiation significantly promoted early cell apoptosis through the mitochondrial apoptosis pathway and exhibited a significant joint function of antitumor efficacy. The demonstrated nGO-COS-CD47/DTIC can provide a highly efficient malignant melanoma therapy using this multifunctional intelligent nanoplatform.

5-Fluorouracil efficacy requires anti-tumor immunity triggered by cancer-cell-intrinsic STING

5-Fluorouracil (5-FU) is a widely used chemotherapeutic drug, but the mechanisms underlying 5-FU efficacy in immunocompetent hosts in vivo remain largely elusive. Through modeling 5-FU response of murine colon and melanoma tumors, we report that effective reduction of tumor burden by 5-FU is dependent on anti-tumor immunity triggered by the activation of cancer-cell-intrinsic STING. While the loss of STING does not induce 5-FU resistance in vitro, effective 5-FU responsiveness in vivo requires cancer-cell-intrinsic cGAS, STING, and subsequent type I interferon (IFN) production, as well as IFN-sensing by bone-marrow-derived cells. In the absence of cancer-cell-intrinsic STING, a much higher dose of 5-FU is needed to reduce tumor burden. 5-FU treatment leads to increased intratumoral T cells, and T-cell depletion significantly reduces the efficacy of 5-FU in vivo. In human colorectal specimens, higher STING expression is associated with better survival and responsiveness to chemotherapy. Our results support a model in which 5-FU triggers cancer-cell-initiated anti-tumor immunity to reduce tumor burden, and our findings could be harnessed to improve therapeutic effectiveness and toxicity for colon and other cancers.

Ex vivo model of human skin (hOSEC) for assessing the dermatokinetics of the anti-melanoma drug Dacarbazine

Alternative models to replace animals in experimental studies remain a challenge in testing the effectiveness of dermatologic and cosmetic drugs. We proposed a model of human organotypic skin explant culture (hOSEC) to assess the profile of cutaneous drug skin distribution, adopting dacarbazine as a model, and respective new methodologies for dermatokinetic analysis. The viability tests were evaluated in primary keratinocytes and fibroblasts, and skin by MTT and TTC assays, respectively. Then, dacarbazine was applied to the culture medium, and the hOSEC method was applied to verify the dynamics of skin distribution of dacarbazine and determine its dermatokinetic profile. The results of cell and tissue viability showed that both were considered viable. The dermatokinetic results indicated that dacarbazine can be absorbed through the skin, reaching a concentration of 36.36 µg/mL (18,18%) of the initial dose (200 µg/mL) after 12 h in culture. Histological data showed that the skin maintained its structure throughout the tested time that the hOSEC method was applied. No apoptotic cells were observed in the epidermal and dermal layers. No visible changes in the dermo-epidermal junction and no inflammatory processes with the recruitment of defense cells were observed. Hence, these findings suggest that the hOSEC concept as an alternative ex vivo model for assessing the dynamics of skin distribution of drugs, such as dacarbazine, and determining their respective dermatokinetic profiles.

Impact of initial treatment and prognostic factors on postprogression survival in BRAF-mutated metastatic melanoma treated with dacarbazine or vemurafenib ± cobimetinib: a pooled analysis of four clinical trials

BACKGROUND

We sought to identify patient subgroups with distinct postprogression overall survival (ppOS) outcomes and investigate the impact of original treatment assignment and initial postprogression treatment (ppRx) on ppOS.

METHODS

Recursive partitioning analysis (RPA) was performed to model relationships between prespecified covariates and ppOS in patients with BRAF^V600-mutated metastatic melanoma who had experienced progressive disease (PD) following treatment with cobimetinib plus vemurafenib, vemurafenib monotherapy, or dacarbazine in the BRIM-2, BRIM-3, BRIM-7, and coBRIM studies. Prognostic subgroups identified by RPA were then applied to pooled treatment cohorts. The primary endpoint was ppOS, defined as time from first PD to death from any cause.

RESULTS

RPA identified baseline lactate dehydrogenase (LDH), baseline disease stage, Eastern Cooperative Oncology Group performance status at PD, and ppRx as significant prognostic factors for ppOS. Median ppOS was longest in patients with normal baseline LDH, stage M1c disease at baseline, and ppRx with immunotherapy or targeted therapy (12.2 months; 95% CI 10.3-16.1) and shortest in those with elevated baseline LDH > 2 × upper limit of normal (2.3 months; 95% CI 1.8-2.7). Original treatment assignment did not impact ppOS. Across treatment cohorts, patients treated with immunotherapy or targeted therapy after PD had better ppOS than those given other treatments.

CONCLUSION

A combination of factors at baseline (LDH, disease stage) and PD (performance status, ppRx) impact ppOS outcomes. ppRx with immunotherapy or targeted therapy is an independent prognostic factor for improved overall survival following progression regardless of original treatment. Trial registration The trials included in this analysis are registered with ClinicalTrials.gov: NCT00949702 (BRIM-2), NCT01006980 (BRIM-3), NCT01271803 (BRIM-7), and NCT01689519 (coBRIM).

Co-delivery of Dacarbazine and All-Trans Retinoic Acid (ATRA) Using Lipid Nanoformulations for Synergistic Antitumor Efficacy Against Malignant Melanoma

Malignant melanoma is a highly aggressive skin cancer responsible for 80% of mortality, and the overall median survival in patients with metastatic melanoma is only 6-9 months. Combination treatment through the simultaneous administration of dual drugs in a single nanocarrier has been demonstrated to be elegant and effective in combatting cancer. Herein, we employ a combination therapy based on dacarbazine (DBZ), FDA approved drug for melanoma and all-trans retinoic acid (ATRA), promising anticancer agents loaded on lipid nanoformulations (RD-LNF) as a new treatment strategy for malignant melanoma. We have successfully encapsulated both the drugs in lipid nanoformulations and showed a controlled release of payload over time. We demonstrated that the simultaneous delivery of DBZ and ATRA could effectively reduce cell proliferation in a concentration-dependent manner. The combinational nanoparticles significantly reduced the colony formation ability of B16F10 melanoma cells. Flow cytometer analysis showed that RD-LNF induced a greater proportion of apoptosis cells with significant inhibition of cell cycle progression and cell migration. These results suggest the promising potential of RD-LNF in the treatment of malignant melanoma with high efficacy.

Adrenocortical carcinoma masquerading as pheochromocytoma: a histopathologic dilemma

SUMMARY

Adrenocortical carcinoma (ACC) is an aggressive cancer that originates in the cortex of the adrenal gland and generally has a poor prognosis. ACC is rare but can be more commonly seen in those with cancer predisposition syndromes (e.g. Li-Fraumeni and Lynch Syndrome). The diagnosis of ACC is sometimes uncertain and it requires the use of precise molecular pathology; the differential diagnosis includes pheochromocytoma, adrenal adenoma, renal carcinoma, or hepatocellular carcinoma. We describe a case of a 57-year-old woman with Lynch Syndrome and metastatic ACC who was initially diagnosed as having pheochromocytoma. The tumor was first identified at 51 years of age by ultrasound followed by a CT scan. She underwent a left adrenalectomy, and the histopathology identified pheochromocytoma. Two years later, she had tumor recurrence with imaging studies showing multiple lung nodules. Following a wedge resection by video-assisted thoracoscopic surgery (VATS), histopathology was read as metastatic pheochromocytoma at one institution and metastatic ACC at another institution. She later presented to the National Institutes of Health (NIH) where the diagnosis of ACC was confirmed. Following her ACC diagnosis, she was treated with mitotane and pembrolizumab which were stopped due to side effects and progression of disease. She is currently receiving etoposide, doxorubicin, and cisplatin (EDP). This case highlights the importance of using a multi-disciplinary approach in patient care. Thorough evaluation of the tumor's pathology and analysis of the patient's genetic profile are necessary to obtain the correct diagnosis for the patient and can significantly influence the course of treatment.

LEARNING POINTS

Making the diagnosis of ACC can be difficult as the differential diagnosis includes pheochromocytoma, adrenal adenoma, renal carcinoma, or hepatocellular carcinoma. Patients with Lynch Syndrome should undergo surveillance for ACC as there is evidence of an association between Lynch Syndrome and ACC. Conducting a complete tumor immunoprofile and obtaining a second opinion is very important in cases of suspected ACC in order to confirm the proper diagnosis. A multi-disciplinary approach including genetic testing and a thorough evaluation of the tumor's pathology is imperative to ensuring that the patient receives an accurate diagnosis and the appropriate treatment.

A systematic literature review and network meta-analysis of effectiveness and safety outcomes in advanced melanoma

BACKGROUND

Although a myriad of novel treatments entered the treatment paradigm for advanced melanoma, there is lack of head-to-head evidence. We conducted a network meta-analysis (NMA) to estimate each treatment's relative effectiveness and safety.

METHODS

A systematic literature review (SLR) was conducted in Embase, MEDLINE and Cochrane to identify all phase III randomised controlled trials (RCTs) with a time frame from January 1, 2010 to March 11, 2019. We retrieved evidence on treatment-related grade III/IV adverse events, progression-free survival (PFS) and overall survival (OS). Evidence was synthesised using a Bayesian fixed-effect NMA. Reference treatment was dacarbazine. In accordance with RCTs, dacarbazine was pooled with temozolomide, paclitaxel and paclitaxel plus carboplatin. To increase homogeneity of the study populations, RCTs were only included if patients were not previously treated with novel treatments.

RESULTS

The SLR identified 28 phase III RCTs involving 14,376 patients. Nineteen and seventeen treatments were included in the effectiveness and safety NMA, respectively. For PFS, dabrafenib plus trametinib (hazard ratio [HR] PFS: 0.21) and vemurafenib plus cobimetinib (HR PFS: 0.22) were identified as most favourable treatments. Both had, however, less favourable safety profiles. Five other treatments closely followed (dabrafenib [HR PFS: 0.30], nivolumab plus ipilimumab [HR PFS: 0.34], vemurafenib [HR PFS: 0.38], nivolumab [HR PFS: 0.42] and pembrolizumab [HR PFS: 0.46]). In contrast, for OS, nivolumab plus ipilimumab (HR OS: 0.39), nivolumab (HR OS: 0.46) and pembrolizumab (HR OS: 0.50) were more favourable than dabrafenib plus trametinib (HR OS: 0.55) and vemurafenib plus cobimetinib (HR OS: 0.57).

CONCLUSIONS

Our NMA identified the most effective treatment options for advanced melanoma and provided valuable insights into each novel treatment's relative effectiveness and safety. This information may facilitate evidence-based decision-making and may support the optimisation of treatment and outcomes in everyday clinical practice.

A sarcoidosis-lymphoma syndrome revealed by hypopituitarism

SUMMARY

A 26-year-old woman presented with persistent headache and tiredness. Biological investigations disclosed a moderate inflammatory syndrome, low PTH-hypercalcemia and complete anterior hypopituitarism. A magnetic resonance imaging (MRI) of the pituitary gland was performed and revealed a symmetric enlargement with a heterogeneous signal. Ophthalmological examination showed an asymptomatic bilateral anterior and posterior uveitis, and a diagnosis of pituitary sarcoidosis was suspected. As the localization of lymphadenopathies on the fused whole-body FDG-PET/computerized tomography (CT) was not evoking a sarcoidosis in first instance, an excisional biopsy of a left supraclavicular adenopathy was performed showing classic nodular sclerosis Hodgkin's lymphoma (HL). A diagnostic transsphenoidal biopsy of the pituitary gland was proposed for accurate staging of the HL and surprisingly revealed typical granulomatous inflammation secondary to sarcoidosis, leading to the diagnosis of a sarcoidosis-lymphoma syndrome. The co-existence of these diseases constitutes a diagnostic challenge and we emphasize the necessity of exact staging of disease in order to prescribe adequate treatment.

LEARNING POINTS

The possibility of a sarcoidosis-lymphoma syndrome, although rare, should be kept in mind during evaluation for lymphadenopathies. In the case of such association, lymphoma usually occurs after sarcoidosis. However, sarcoidosis and lymphoma can be detected simultaneously and development of sarcoidosis in a patient with previous lymphoma has also been reported. An accurate diagnosis of the disease and the respective organ involvements, including biopsy, is necessary in order to prescribe adequate treatment.

A phase II study of the L19IL2 immunocytokine in combination with dacarbazine in advanced metastatic melanoma patients

Engineered cytokine products represent promising agents for the treatment of immunogenic tumors, such as malignant melanoma, in addition to immune checkpoint inhibitors. Here we describe the results of a controlled, randomized phase II clinical trial, aimed at assessing the therapeutic potential of L19IL2, a fully human fusion protein consisting of the L19 antibody specific to the alternatively spliced extra-domain B of fibronectin, fused to human interleukin-2 in advanced metastatic melanoma. In one arm, patients received dacarbazine (DTIC; 1000 mg/m² of body surface on day 1 of 21-day cycles) as single agent, while in two other arms L19IL2 (22.5 million international units of IL2 equivalents) was added, based on two different schedules of administration. In total, 69 patients with stage IV melanoma were enrolled (24 in the dacarbazine arm, 23 and 22 in the other combination arms, respectively) and 67 received treatment. Analyses of efficacy results show a statistically significant benefit in terms of overall response rate and median progression-free survival for patients receiving L19IL2 in combination with DTIC, compared to DTIC as single agent. In light of these results, further clinical investigations with L19IL2 (alone or in combination with other agents) are warranted.

Photochemically stabilized formulation of dacarbazine with reduced production of algogenic photodegradants

The present study aimed to develop a photochemically stabilized formulation of dacarbazine [5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide; DTIC] for reducing the production of algogenic photodegradant (5-diazoimidazole-4-carboxamide; Diazo-IC). Photochemical properties of DTIC were characterized by UV-visible light spectral analysis, reactive oxygen species (ROS) assay, and photostability testing. A pharmacokinetic study was conducted after intravenous administration of DTIC formulations (1 mg-DTIC/kg) to rats. DTIC exhibited strong absorption in the UVA range, and photoirradiated DTIC exhibited marked ROS generation. Thus, DTIC had high photoreactive potential. After exposure of DTIC (1 mM) to simulated sunlight (250 W/m²) for 3 min, remaining DTIC and yielded Diazo-IC were estimated to be ca. 230 μM and 600 μM, respectively. The addition of radical scavenger (1 mM), including l-ascorbic acid, l-cysteine (Cys), l-histidine, D-mannitol, l-tryptophan, or l-tyrosine, to DTIC (1 mM) could attenuate DTIC photoreactions, and in particular, the addition of Cys to DTIC brought ca. 34% and 86% inhibition of DTIC photodegradation and Diazo-IC photogeneration, respectively. There were no significant differences in the calculated pharmacokinetic parameters of DTIC between DTIC and DTIC with Cys (0.67 mg/kg). From these findings, the supplementary use of Cys would be an effective approach to improve the photostability of DTIC with less production of Diazo-IC.

Double trouble: two cases of dual adrenal pathologies in one adrenal mass

Context Adrenal incidentalomas (AI) represent an increasingly common problem in modern endocrine practice. The diagnostic approach to AIs can be challenging and occasionally reveals surprising features. Here we describe two rare cases of complex adrenal lesions consisting of phaeochromocytomas with synchronous metastases from extra-adrenal primaries. Case descriptions Patient 1 - a 65-year-old gentleman with a newly diagnosed malignant melanoma was found to harbour an adrenal lesion with suspicious radiographic characteristics. Percutaneous adrenal biopsy was consistent with adrenocortical adenoma. After excision of the skin melanoma and regional lymphatic metastases, he was followed up without imaging. Three years later, he presented with abdominal discomfort and enlargement of his adrenal lesion, associated with high plasma metanephrines. Adrenalectomy revealed a mixed tumour consisting of a large phaeochromocytoma with an embedded melanoma metastasis in its core. Patient 2 - a 63-year-old lady with a history of NF-1-related phaeochromocytoma 20 years ago and previous breast cancer presented with a new adrenal lesion on the contralateral side. Plasma normetanephrine was markedly elevated. Elective adrenalectomy revealed an adrenal tumour consisting of chromaffin cells intermixed with breast carcinoma cells. Conclusions Adrenal incidentalomas require careful evaluation to exclude metastatic disease, especially in the context of a history of previous malignancy. Adrenal biopsy provides limited and potentially misleading information. Phaeochromocytomas are highly vascularised tumours that may function as a sieve, extracting and retaining irregularly shaped cancer cells, thereby yielding adrenal masses with intriguing dual pathology. Learning points: Adrenal incidentalomas require careful evaluation focused on exclusion of underlying hormone excess and malignant pathology. Adrenal biopsy can be misleading and should only be considered in select cases. Phaeochromocytomas harbouring intratumoural metastases from other, extra-adrenal primary malignancies represent rare pathological entities that highlight the complexities that can be presented by adrenal tumours.

Comparison of Temozolomide-Capecitabine to 5-Fluorouracile-Dacarbazine in 247 Patients with Advanced Digestive Neuroendocrine Tumors Using Propensity Score Analyses

INTRODUCTION

Although chemotherapy combining 5-fluorouracil (5FU)-dacarbazine (DTIC) or temozolomide (TEM)-capecitabine (CAP) is extensively used in patients with neuroendocrine tumors (NET), they were never compared. We compared their tolerance and efficacy in advanced NET.

METHODS

We evaluated the records of consecutive patients with pancreatic or small-intestine advanced NET who received 5FU-DTIC or TEM-CAP between July 2004 and December 2017 in 5 French centers. Tolerance, tumor response and progression-free survival (PFS) were compared. Factors associated with PFS were analyzed using Cox multivariate regression model. To reduce the confounding bias of the nonrandomized design, PFS was compared using propensity score analyses.

RESULTS

Ninety-four (5FU-DTIC) patients and 153 (TEM-CAP) patients were included. Pancreatic NET represented 82.3% of cases and 17.1, 61.8 and 10.9% of patients had G1, G2 or G3 NET respectively. Progression at baseline was reported in 92.7% of patients with available data. Grades 3-4 adverse events occurred in 24.7 and 8.5% of TEM-CAP and 5FU-DTIC patients respectively (p = 0.002). The overall response rate was 38.3 and 39.2% respectively (p = 0.596). Median PFS on raw analysis was similar to 5FU-DTIC and TEM-CAP (13.9 vs. 18.3 months, respectively p = 0.86). TEM-CAP was associated with an increased risk of progression on the raw multivariate analysis (hazard ratio [HR] 1.90, 95% CI [1.32-2.73], p = 0.001) and when adjusted on propensity score (HR 1.65, 95% CI [1.18-2.31], p = 0.004).

CONCLUSION

PFS may be longer with 5FU-DTIC than TEM-CAP in patients with advanced NET. Although patients often prefer oral chemotherapy, 5FU-DTIC is a relevant alternative. A randomized comparison is needed to confirm these results.

Post-treatment de-phosphorylation of p53 correlates with dasatinib responsiveness in malignant melanoma

BACKGROUND

Dasatinib (Sprycel) was developed as a tyrosine kinase inhibitor targeting Bcr-Abl and the family of Src kinases. Dasatinib is commonly used for the treatment of acute lymphoblastic and chronic myelogenous leukemia. Previous clinical studies in melanoma returned inconclusive results and suggested that patients respond highly heterogeneously to dasatinib as single agent or in combination with standard-of-care chemotherapeutic dacarbazine. Reliable biomarkers to predict dasatinib responsiveness in melanoma have not yet been developed.

RESULTS

Here, we collected comprehensive in vitro data from experimentally well-controlled conditions to study the effect of dasatinib, alone and in combination with dacarbazine, on cell proliferation and cell survival. Sixteen treatment conditions, covering therapeutically relevant concentrations ranges of both drugs, were tested in 12 melanoma cell lines with diverse mutational backgrounds. Melanoma cell lines responded heterogeneously and, importantly, dasatinib and dacarbazine did not synergize in suppressing proliferation or inducing cell death. Since dasatinib is a promiscuous kinase inhibitor, possibly affecting multiple disease-relevant pathways, we also determined if basal phospho-protein amounts and treatment-induced changes in phospho-protein levels are indicative of dasatinib responsiveness. We found that treatment-induced de-phosphorylation of p53 correlates with dasatinib responsiveness in malignant melanoma.

CONCLUSIONS

Loss of p53 phosphorylation might be an interesting candidate for a kinetic marker of dasatinib responsiveness in melanoma, pending more comprehensive validation in future studies.

Reversing effect of Lupeol on vasculogenic mimicry in murine melanoma progression

Vasculogenic mimicry, an endothelia-independent tumor microcirculation has been found in various cancers and is thought to be achieved by cancer stem like cells. Dacarbazine resistance is one of the most common features of melanoma and recent studies suggest that the mode of resistance is closely related to the formation of vasculogenic mimicry. In our work, we examined the anticancer effect of Lupeol, a novel phytochemical with Dacarbazine in vivo and in vitro. Results demonstrated adequate cytotoxicity followed by down regulation of CD 133 expression in Lupeol treated B16-F10 cell line. In solid tumor model the drug also inhibited vasculogenic mimicry along with angiogenesis by altering both the cancer stem cell as well as the endothelial progenitor cell population. Lupeol hindered the maturation of bone marrow derived endothelial progenitors and thus, retarded the formation of rudimentary tumor microvessels. Notably, Dacarbazine treatment demonstrated unresponsiveness to B16-F10 cells in both in vivo and in vitro model via upregulation of CD 133 expression and increased formation of vasculogenic mimicry tubes. Together, these data indicate that Lupeol alone can become a proficient agent in treating melanoma, inhibiting vasculogenic mimicry and might play a significant role in subduing Dacarbazine induced drug resistance.

The Role of Cytotoxic Chemotherapy in Advanced Pancreatic Neuroendocrine Tumors

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are rare neoplasms accounting for less than 5% of all pancreatic malignancies. These tumors are characterized by clinical and prognostical heterogeneity and are predominantly diagnosed in a metastatic stage. Cytotoxic chemotherapy, along with alkylating agents and antimetabolites as well as molecular targeted agents (everolimus, sunitinib), is used in the treatment of advanced PNETs. After the approval of lanreotide for unresectable PNETs, an additional therapeutic option has become available; however, the best sequence of therapies and patient stratification to different treatments remains challenging. Furthermore, no randomized phase-3 trials or head-to-head comparisons are available to support treatment decisions.

SUMMARY

The publication of 3 large single-center retrospective studies on streptozocin-(STZ)-based chemotherapy in advanced PNETs in 2015 confirmed the effectiveness of this treatment as described in previously reported trials. All studies investigated markers for progression-free and overall survival and strongly supported the value of the Ki-67 index as a robust prognostic marker. Interestingly, chemotherapy consistently displayed antitumor efficacy in different therapeutic lines. Moreover, a recent study of dacarbazine (DTIC) in a cohort of patients predominantly with PNETs demonstrated that a once monthly infusional DTIC schedule was well tolerated and yielded similar response rates (RR) as STZ-based schedules. Given the overall good tolerability of a monthly infusion and RR similar to STZ schedules, DTIC thus represents a feasible alternative or additional treatment option for PNETs. In this article, we review the current standard and summarize the most recent advances in the field of cytotoxic chemotherapy for PNET patients. Key Messages: (1) Despite the lack of phase3 trials, cytotoxic chemotherapy offers efficacy for patients with advanced PNETs; (2) the best therapeutic option and sequence remain open since comparable randomized studies are lacking; (3) careful patient selection and treatment stratification may increase overall outcome; and (4) currently, no biomarkers for clinical routine exist to predict response to chemotherapy.

Toxicities, safeties and clinical response of dacarbazine-based chemotherapy on neuroendocrine tumors in Taiwan population

BACKGROUND

Currently, the role of dacarbazine (DTIC) based chemotherapy in neuroendocrine tumors (NETs) in Asia is unclear. Here, we report the outcomes of dacarbazine (DTIC)-based chemotherapy in Taiwan population.

METHODS

DTIC alone (250 mg/m²/day), or 5-fluorouracil (5-FU, 500 mg/m²/day) and DTIC (200 mg/m²/day) with or without epirubicin (200 mg/m²/day), for 3 days, every 3-4 weeks. Subgroups were analyzed by grading, and by Ki-67 index.

RESULTS

48 patients were reviewed in this study, including 3 had grade 1 tumors, 23 had grade 2, while 22 were grade 3. In grade 3 NEC patients, the tumor Ki-67 index of 21-55% were noted in 8 patients, and >55% in 14 patients. Progression-free survival (PFS) was 5.1 months, and overall survival (OS) was 31.6 months. The PFS (in months) were 12.5 and 1.8 for patients with NETs and neuroendocrine carcinomas (NECs), respectively (p < 0.001). The OS were not reached and 5.9 months for patients with NETs and NECs, respectively (p = 0.001). Patients with NECs were divided into two groups, according to their Ki-67 index. In patients with a tumor Ki-67 index of 21-55%, PFS was 4.1 months, and OS was not reached; in those with a tumor Ki-67 index of >55%, they were 1.5 and 1.8 months, respectively (p < 0.001 and p = 0.013).

CONCLUSION

NETs, and grade 3 NECs, with Ki-67 indices of 20-55% had good responses to DTIC-based chemotherapy, with acceptable side effects. Ki-67 index could predict prognosis for grade 3 NEC patients, and guide further chemotherapy choices.

Continued Tumor Reduction of Metastatic Pheochromocytoma/Paraganglioma Harboring Succinate Dehydrogenase Subunit B Mutations with Cyclical Chemotherapy

Patients harboring germline mutations in the succinate dehydrogenase complex subunit B (SDHB) gene present with pheochromocytomas and paragangliomas (PPGL) that are more likely malignant and clinically aggressive. The combination chemotherapy cyclophosphamide, vincristine, and dacarbazine (CVD) was retrospectively evaluated in patients with SDHB-associated metastatic PPGL.Query Twelve metastatic PPGL patients harboring SDHB mutations/polymorphisms with undetectable SDHB immunostaining were treated with CVD. CVD therapy consisted of 750 mg/m² cyclophosphamide with 1.4 mg/m² vincristine on day 1 and 600 mg/m² dacarbazine on days 1 and 2, every 21-28 days. Treatment outcome was determined by RECIST criteria as well as determination of response duration and progression-free and overall survivals. A median of 20.5 cycles (range 4-41) was administered. All patients had tumor reduction (12-100% by RECIST). Complete response was seen in two patients, while partial response was observed in 8. The median number of cycles to response was 5.5. Median duration of response was 478 days, with progression-free and overall survivals of 930 and 1190 days, respectively. Serial [¹⁸F]-fluorodeoxyglucose positron emission tomography and computed tomography imaging demonstrated continued incremental reduction in maximal standardized uptake values (SUV_max) values in 26/30 lesions. During treatment administration, the median SUV decreased from > 25 to < 6, indicating the efficacy of chemotherapy over a prolonged period of time. Prolonged therapy results in continued incremental tumor reduction, and is consistent with persistent drug sensitivity. CVD chemotherapy is recommended to be considered part of the initial management in patients with metastatic SDHB-related PPGL.

Pharmacokinetics of dacarbazine (DTIC) in pregnancy

PURPOSE

The purpose of this report is to describe, for the first time, the pharmacokinetics of dacarbazine (DTIC) and its metabolites [5-[3-methyl-triazen-1-yl]-imidazole-4-carboxamide (MTIC), 5-[3-hydroxymethyl-3-methyl-triazen-1-yl]-imidazole-4-carboxamide (HMMTIC) and 5-aminoimidazole-4-carboxamide (AIC)] during pregnancy (n = 2) and postpartum (n = 1).

METHODS

Non-compartmental DTIC, MTIC, HMMTIC, and AIC pharmacokinetics (PK) were estimated in one case at 29 week gestation and 18 day postpartum and a second case at 32 week gestation, in women receiving DTIC in combination with doxorubicin, bleomycin, and vinblastine for treatment of Hodgkin's lymphoma. Drug concentrations were measured by HPLC.

RESULTS

In the subject who completed both pregnancy and postpartum study days, DTIC area under the concentration-time curve (AUC) was 27% higher and metabolite AUCs were lower by 27% for HMMTIC, 38% for MTIC, and 83% of AIC during pregnancy compared to postpartum. At 7 and 9 year follow-up, both subjects were in remission of their Hodgkin's lymphoma.

CONCLUSIONS

Based on these two case reports, pregnancy appears to decrease the metabolism of the pro-drug dacarbazine, likely through inhibition of CYP1A2 activity. Lower concentrations of active metabolites and decreased efficacy may result, although both these subjects experienced long-term remission of their Hodgkin's lymphoma.

Dacarbazine-Loaded Hollow Mesoporous Silica Nanoparticles Grafted with Folic Acid for Enhancing Antimetastatic Melanoma Response

Dacarbazine (DTIC) is one of the most important chemotherapeutic agents for the treatment of melanoma; however, its poor solubility, photosensitivity, instability, and serious toxicity to normal cells limit its clinical applications. In this article, we present a rationally designed nanocarrier based on hollow mesoporous silica nanoparticles (HMSNs) for the encapsulation and targeted release of DTIC for eradicating melanoma. The nanocarrier (DTIC@HMLBFs) is prepared by modifying HMSNs with carboxyl groups to enhance the loading of DTIC, followed by further enveloping of folic acid-grafted liposomes, which act as a melanoma active target for controlled and targeted drug release. In vitro, DTIC@HMLBFs exhibited the strongest cytotoxicity to melanoma cells compared with DTIC@HMSNs and free DTIC. The in vivo investigations demonstrate that the rationally designed nanocarrier loaded with DTIC achieves significant improvement against lung metastasis of melanoma via targeting melanoma cells and tumor-associated macrophages. This study provides a promising platform for the design and fabrication of multifunctional nanomedicines, which are potentially useful for the treatment of melanoma.

Efficacy and safety of trabectedin or dacarbazine in patients with advanced uterine leiomyosarcoma after failure of anthracycline-based chemotherapy: Subgroup analysis of a phase 3, randomized clinical trial

OBJECTIVE

Trabectedin demonstrated significantly improved disease control in leiomyosarcoma and liposarcoma patients in a global phase 3 trial (NCT01343277). A post hoc analysis was conducted to assess the efficacy and safety of trabectedin or dacarbazine in women with uterine leiomyosarcoma (uLMS), the largest subgroup of enrolled patients (40%).

METHODS

Of 577 patients randomized 2:1 to receive trabectedin 1.5mg/m² by 24-hour IV infusion or dacarbazine 1g/m² by 20-120-minute IV infusion once every three weeks, 232 had uLMS (trabectedin: 144; dacarbazine: 88). The primary endpoint was overall survival (OS); secondary endpoints were progression-free survival (PFS), objective response rate (ORR), clinical benefit rate (CBR: complete responses+partial responses+stable disease [SD] for at least 18weeks), duration of response (DOR), and safety.

RESULTS

PFS for trabectedin was 4.0months compared with 1.5months for dacarbazine (hazard ratio [HR]=0.57; 95% CI 0.41-0.81; P=0.0012). OS was similar (trabectedin 13.4months vs. dacarbazine 12.9months, HR=0.89; 95% CI 0.65-1.24; P=0.51) between groups. ORR was 11% with trabectedin vs. 9% with dacarbazine (P=0.82). CBR for trabectedin was 31% vs. 18% with dacarbazine (P=0.05); median DOR was 6.5months for trabectedin vs. 4.1months for dacarbazine (P=0.32). Grade 3/4 treatment-emergent adverse events observed in ≥10% of patients in the trabectedin group included transient aminotransferase (aspartate/alanine) elevations, anemia, leukopenia, and thrombocytopenia.

CONCLUSIONS

In this post hoc subset analysis of patients with uLMS who had received prior anthracycline therapy, trabectedin treatment resulted in significantly longer PFS versus dacarbazine, with an acceptable safety profile. There was no difference in OS.

A phase I dose-escalation study of selumetinib in combination with docetaxel or dacarbazine in patients with advanced solid tumors

Background

The RAS/RAF/MEK/ERK pathway is constitutively activated in many cancers. Selumetinib (AZD6244, ARRY-142886) is an oral, potent and highly selective, allosteric MEK1/2 inhibitor with a short half-life that has shown clinical activity as monotherapy in phase I and II studies of advanced cancer. Preclinical data suggest that selumetinib may enhance the activity of chemotherapeutic agents. We assessed the safety, tolerability, and pharmacokinetics (PK) of selumetinib (AZD6244, ARRY-142886) in combination with docetaxel or dacarbazine in patients with advanced solid tumors.

Methods

This study was a phase I, open-label, multicenter study in patients aged ≥18 years with advanced solid tumors who were candidates for docetaxel or dacarbazine treatment. Part A of the study (dose escalation) evaluated safety, tolerability, PK, and maximum tolerated dose (MTD) of selumetinib twice daily (BID) with docetaxel 75 mg/m² or dacarbazine 1000 mg/m² administered every 21 days. Patients receiving docetaxel could be administered primary prophylactic granulocyte-colony stimulating factor according to standard guidelines. Part B of the study (dose expansion) further evaluated safety, tolerability, and PK in 12 additional patients at the MTD combinations determined in part A.

Results

A total of 35 patients received selumetinib plus docetaxel, and 25 received selumetinib plus dacarbazine. The MTD of selumetinib was 75 mg BID in combination with either docetaxel (two dose-limiting toxicity [DLT] events: neutropenia with fever, and thrombocytopenia) or dacarbazine (one DLT event: thrombocytopenia). Common adverse events occurring with each treatment combination were diarrhea, peripheral/periorbital edema, fatigue, and nausea. PK parameters for selumetinib and docetaxel or dacarbazine were similar when administered alone or in combination. Partial responses were reported in 6/35 patients receiving selumetinib plus docetaxel and 4/25 patients receiving selumetinib plus dacarbazine.

Conclusions

The combinations of selumetinib plus docetaxel and selumetinib plus dacarbazine demonstrated manageable safety and tolerability profiles and preliminary signs of clinical activity in patients with advanced solid tumors.

Trial registration

ClinicalTrials.gov NCT00600496; registered 8 July 2009.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3143-6) contains supplementary material, which is available to authorized users.

Adenovirus-based strategies enhance antitumor capability through p53-mediated downregulation of MGMT in uveal melanoma

Uveal melanoma (UM) is an intractable disease with a low survival rates, despite adequate local treatment, as a result of its metastatic characteristics. Thus, new therapeutic strategies, including combinations of novel gene therapy and traditional chemotherapy, are under investigation to improve long-term prognosis. Dacarbazine or DTIC, an alkylating agent which results in DNA methylation, is most commonly used to treat melanoma but the response is very limited. The O6-methylguanine DNA methyl transferase (MGMT), a DNA repair protein, is involved in chemoresistance in DTIC treatment. We previously investigated a combination of oncolytic adenovirus H101 and the alkylating agent DTIC in the treatment of UM cells in vitro and observed a synergistic antitumor effect. In this study, we validated this result and report an enhanced therapeutic effect in vivo. Our findings also demonstrated that the oncolytic adenovirus H101 decreased MGMT levels via accumulation of p53 overcoming DTIC chemoresistance. Therefore, the clinical therapeutic efficacy of DTIC in the treatment of UM might be improved using this adenovirus-based combination therapy.

Relative Efficacy of Granulocyte-Macrophage Colony-Stimulating Factor, Dacarbazine, and Glycoprotein 100 in Metastatic Melanoma: An Indirect Treatment Comparison

INTRODUCTION

Advances in the treatment of metastatic melanoma have been achieved in recent years: immunotherapies and targeted therapies have demonstrated survival benefits over older agents such as granulocyte-macrophage colony-stimulating factor (GM-CSF), dacarbazine, and glycoprotein peptide vaccine (gp100) in pivotal phase 3 trials. It is important to compare therapies to guide the treatment decision-making process, and establishing the relationship between older agents can strengthen the networks of evidence for newer therapies. We report the outcome of an indirect comparison of GM-CSF, dacarbazine, and gp100 in metastatic melanoma through meta-analysis of absolute treatment effect.

METHODS

A systematic literature review identified trials for inclusion in the meta-analysis. A valid network meta-analysis was not feasible: treatment-specific meta-analysis was conducted. A published algorithm was used to adjust overall survival estimates from trials of GM-CSF, dacarbazine, and gp100 for heterogeneity in baseline prognostic factors. Survival estimates were compared in three patient groups: stage IIIB-IV M1c, stage IIIB-IV M1a, and stage IV M1b/c.

RESULTS

One trial of GM-CSF, four of dacarbazine, and one of gp100 were included in the analysis. After adjusting for differences in baseline prognostic factors, median overall survival (OS) in all patient groups was longer for those receiving GM-CSF than for those receiving dacarbazine or gp100. The observed survival over time for GM-CSF was similar to the adjusted survival for dacarbazine and greater than for gp100 in all patient groups.

CONCLUSION

The relative treatment effect of GM-CSF, dacarbazine, and gp100 has been reliably estimated by adjusting for differences in baseline prognostic factors. Results suggest that OS with GM-CSF is at least as good as with dacarbazine and greater than with gp100. Given the role of these agents as controls in phase 3 trials of new immunotherapies and targeted agents, these results can be used to contextualize the efficacy of newer therapies.

FUNDING

Amgen Inc.

A combination of photodynamic therapy and chemotherapy displays a differential cytotoxic effect on human metastatic melanoma cells

BACKGROUND

Cutaneous melanoma represents the most lethal form of skin cancer and remains refractory to current therapies. Failure of treatment has been attributed to the over-expression of ABC transporters which efflux the drugs, below their cytotoxic threshold within cells. Therefore, this study set to investigate; the efficacy of a combinatorial approach comprising chemotherapy (Dacarbazine) and photodynamic therapy (PDT) to overcome resistance in pigmented and unpigmented metastatic melanoma and potentially identify resistant mechanisms.

METHODS

The cytotoxic effect of the chemotherapy, PDT and combination therapy treatment (Dacarbazine+PDT) was determined using a cell viability XTT assay. Thereafter, melanoma cells morphology, self-renewal capacity and ABCG2 protein expression, were determined using fluorescence microscopy, clonogenic assay, western blot and flow cytometry. All results were analyzed by t-test and ANOVA, followed by individual comparisons with post-tests.

RESULTS

This study describes possible synergism of PDT+DTIC in reducing melanoma cell viability in vitro. At 24h post-treatment, only the unpigmented melanomas were sensitive to DTIC treatment (20-25% death at 1.25mM). At 48h, a lethal dose of 50% was reached in these cells in contrast to the pigmented melanoma (20% at 48h). The same trend was observed with the combination therapy (DTIC+PDT) at both time points. Furthermore, complete morphological disruption could be observed upon PDT only and PDT+DTIC treatments. Moreover, PDT and DTIC+PDT suppressed the self-renewal capacity of both melanoma cell lines. No significant differences in ABCG2 protein expression was found at 24h post-treatment.

CONCLUSION

Overall, these results suggest that human melanomas remain heterogeneous in their phenotypes. Moreover, in our metastatic melanoma cells, ABCG2 transporters did not seem to be involved in resistance to therapies. Significantly though, a combinatorial approach of PDT and chemotherapy significantly decreases the self-renewal capacity of metastatic melanoma cells and could be a suggested adjunctive approach to post-resection treatment regimes.

Reduction of Dacarbazine cytogenetic effects on somatic cells in male mice using bee glue (Propolis) to manifest the scientific miracles in the Quran

Objective

This study was carried out to investigate the ability of Propolis to ameliorate the adverse cytogenetic effects of Dacarbazine on bone marrow cells

Methods

In this experimental in vivo study, 18 mice were used, divided into four groups: control group; Propolis-treated group (treated with 50mg/kg Propolis); and Dacarbazine-treated group (treated with 3.5mg/kg Dacarbazine). The fourth, fifth, and sixth were treated with Dacarbazine and Propolis as pre 2h, post 2h, and concomitant treatment. After five days, the Bone Marrow (BM) samples were obtained for cytogenetic investigation.

Results

The in vivo studies revealed that Dacarbazine induced an abnormalities in polychromatic erythrocytes cells (PECs) as increase of cell with micronuclei, while the dual treatment accompanied with improvement of this abnormalities.

Conclusions

It could be concluded that there are protective effects of Propolis against the adverse effects of Dacarbazine. It could be recommended to use Propolis as an adjuvant with chemotherapeutic agents.

The simulation of UV spectroscopy and electronic analysis of temozolomide and dacarbazine chemical decomposition to their metabolites

The electronic features of anti-tumor agent, temozolomide, and its degradation products (MTIC and metabolite AIC) have been traced by means of UV absorption spectroscopy in vacuo and aqueous media. For comparison, electronic spectra of related structures and drugs (e.g., dacarbazine) were also investigated. These investigations were carried out using time-dependent density functional theory (TD-DFT) method while the conductor like screening model (COSMO) were applied for the inclusion of solvent effects in electronic spectra. From functional benchmarking, two methods; B3LYP and O3LYP were selected among several other methods with 6-311+G(2d,p) basis set aiming to get the best results in accord with the experimental values. An assessment of the obtained spectra has shown that O3LYP functional gives a mean absolute error (MAE) from experimental absorption peaks of 4.3 nm compared to the 7.2 nm MAE value at B3LYP level in aqueous media. Furthermore, since the structural and tautomeric conformers affect the electronic spectra, conformational preferences have been analyzed in temozolomide, dacarbazine, and their related structures. Temozolomide structure possesses two rotamers that differ in the orientation of carboxamide moiety with a small energy difference (energy difference of 1.39 kcal mol^-1 in vacuo and 0.35 kcal mol^-1 in aqueous media at B3LYP/6-311++G(2df,3pd). The more stable and meta-stable TMZ rotamer have shown their absorption maxima at 329-334 nm, respectively, at O3LYP level in aqueous media. Applying statistical calculation according to Boltzmann population formula at 25 °C and computed weighed mean estimates the λ_max of temozolomide at 331 nm, which is in notable agreement with the experimental value (330 nm). Moreover, molecular orbital composition analysis has been conducted in order to interpret these findings. Graphical Abstract Temozolomide and dacarbazine.

Low dose DTIC is effective and safe in pretreated patients with well differentiated neuroendocrine tumors

Background

Streptozocin (STZ) based chemotherapy is recommended for patients with metastatic pancreatic neuroendocrine tumors (pNET). Temozolomide as mono- or combination therapy has been suggested to be a promising alternative. However, the treatment is costly and not approved for the treatment of pNETs. Dacarbazine (DTIC) shares the active metabolite with temozolomide and is broadly available at a low cost. The aim of this study was a retrospective evaluation of the efficacy and tolerability of a lower dose DTIC-regimen in patients with progressive advanced NETs.

Methods

We retrospectively analyzed 75 patients with NETs predominantly of pancreatic origin treated at our center between 1998 and 2013. 650 mg/m² of DTIC were administered intravenously over 60 min every 4 weeks. Morphological response was assessed according to RECIST1.1 criteria. The median progression free survival (PFS) was calculated using Kaplan-Meier and Cox regression methods, respectively. Univariate analyses of possible prognostic markers were performed.

Results

The objective response rate (ORR) was 27 % for the entire cohort and 32 % in 50 pNET patients, respectively. Stable disease (SD) was documented in 29 patients (39 %). Median PFS (mPFS) in patients receiving DTIC was 7 months (3.9–10; 95 % confidence interval). Radiological and biochemical response were the only significant prognostic markers for longer PFS in univariate analysis. Treatment was well tolerated. Nausea was the most common side effect (31 %), only one case (1.3 %) of grade 3 toxicity (vomiting) occurred.

Conclusion

Low dose DTIC chemotherapy is an effective and well-tolerated treatment option in patients with progressive well differentiated neuroendocrine neoplasms, especially of pancreatic origin.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2642-1) contains supplementary material, which is available to authorized users.

Increased Infiltration of CD8(+) T Cells by Dacarbazine in a Patient with Mucosal Penile Melanoma Refractory to Nivolumab

Primary penile melanomas are rare tumors that represent less than 0.1% of all melanomas. We report a case of a 60-year-old Japanese male with a mucosal penile melanoma and describe an increased CD8⁺ T cell infiltration in brain after dacarbazine (DTIC) administration. After partial penectomy and left inguinal lymphadenectomy, he developed multiple lung, bone, spleen, brain and skin metastases. He was treated with interferon-β, DTIC and nivolumab. However, the metastases were not reduced in size. Immunohistochemistry showed an increase of CD8⁺ T cell infiltration and programmed death-ligand 1 (PD-L1) expression after the administration of DTIC, but the expression of programmed cell death protein 1 (PD-1) was negative. We speculate that DTIC exerted immunostimulatory effects, but nivolumab was ineffective due to the negative expression of PD-1 and/or an insufficient infiltration of CD8⁺ T cells. Although this is only one case, this case report could be the first step to discuss the development of effective therapies against melanoma to take advantage of the increased CD8⁺ T cell infiltration elicited by chemotherapeutic agents. It would be beneficial to pay more attention to the relationship between DTIC and immune checkpoint modulators.

Dacarbazine

Dacarbazine is a cell cycle nonspecific antineoplastic alkylating agent used in the treatment of metastatic malignant melanoma. This chapter contains the descriptions of the drug: nomenclature, formulae, chemical structure, elemental composition, and appearance. The uses and applications of dacarbazine and the methods that were used for its preparation are reported. The methods which were used for the physical characterization of the drug are ionization constant, solubility, X-ray powder diffraction pattern, crystal structure, melting point, and differential scanning calorimetry. The profile contains the spectra of the drug: ultraviolet spectrum, vibrational spectrum, nuclear magnetic resonance spectra, and mass spectrum. The compendial methods of analysis for dacarbazine include the United States Pharmacopeia methods, British Pharmacopeia methods, and International Pharmacopeia methods. Other reported methods that are used for the analysis of the drug are high-performance liquid chromatography, high-performance liquid chromatography-mass spectrometry, and polarography. Metabolism, pharmacokinetics, and stability studies on dacarbazine are also included. Reviews of some analytical methods and physicochemical properties of the drug as well as the most important enzymes that are involved in the prodrug activation are provided. Sixty-four references are listed at the end of this monograph.

Chemotherapy for Melanoma. Cancer Treat Res. 2016;167:209-229. [PMID: 26601864 DOI: 10.1007/978-3-319-22539-5_8]

Prior to the recent therapeutic advances, chemotherapy was the mainstay of treatment options for advanced-stage melanoma. A number of studies have investigated various chemotherapy combinations in order to expand on the clinical responses achieved with single-agent dacarbazine, but these have not demonstrated an improvement in overall survival. Similar objective responses were observed with the combination of carboplatin and paclitaxel as were seen with single-agent dacarbazine. The combination of chemotherapy and immunotherapy, known as biochemo-therapy, has shown high clinical responses; however, biochemo-therapy has not been shown to improve overall survival and resulted in increased toxicities. In contrast, palliation and long-term responses have been observed with localized treatment with isolated limb perfusion or infusion in limb-isolated disease. Although new, improved therapeutic options exist for first-line management of advanced-stage melanoma, chemotherapy may still be important in the palliative treatment of refractory, progressive, and relapsed melanoma. We review the various chemotherapy options available for use in the treatment and palliation of advanced-stage melanoma, discuss the important clinical trials supporting the treatment recommendations, and focus on the clinical circumstances in which treatment with chemotherapy is useful.

The Cytotoxicity of Dacarbazine Potentiated by Sea Cucumber Saponin in Resistant B16F10 Melanoma Cells through Apoptosis Induction

BACKGROUND

Malignant melanoma is a highly aggressive malignant melanocytic neoplasm which resists against the most conventional therapies. Sea cucumber as one of marine organisms contains bioactive compounds such as polysaccharide, terpenoid and other metabolites which have anti-cancer, anti-tumor, anti-inflammatory and antioxidant properties. The present study was designed to investigate the anticancer potential of saponin extracted from sea cucumber Holothuria leucospilata alone and in combination with dacarbazine on B16F10 melanoma cell line.

METHODS

The B16F10 cell line was treated with different concentrations of saponin (0, 4, 8, 12, 16, 20 μg/ml), dacarbazine (0, 1200, 1400, 1600, 18000, 1200, 1400, 1600, 2000 μg/ml) and co-administration of saponin-dacarbazine (1200 da+8 sp, 1200 da+4 sp) for 24 and 48 hr and the cytotoxic effect was examined by MTT, DAPI, acridine orange/propodium iodide, flow cytometry and caspase colorimetric assay.

RESULTS

The results exhibited that sea cucumber saponin, dacarbazine, and co-administration of saponin-dacarbazine inhibited the proliferation of melanoma cells in a dose and time dependent manner with IC50 values of 10, 1400 and 4+1200 μg/ml, respectively. Morphological observation of DAPI and acridine orange/propodium iodide staining documented typical characteristics of apoptotic cell death. Flow cytometry assay indicated accumulation of IC50 treated cells in sub-G1 peak. Additionally, saponin extracted induced intrinsic apoptosis via up-regulation of caspase-3 and caspase-9.

CONCLUSION

These results revealed that the saponin extracted from sea cucumber as a natural anti-cancer compound may be a new treatment modality for metastatic melanoma and the application of sea cucumber saponin in combination with dacarbazine demonstrated the strongest anti-cancer activity as compared with the drug alone.

Infrared spectra of primary melanomas can predict response to chemotherapy: The example of dacarbazine

Metastatic melanomas are highly aggressive and median survival is 6-9months for stage IV patients in the absence of treatment with anti-tumor activity. Dacarbazine is an alkylating agent that has been widely used in the treatment of metastatic melanomas and that could be still used in combination with targeted or immune therapies. Indeed, therapeutic benefits of these treatments in monotherapy are poor and one option to improve them is to combine drugs and/or to better anticipate the individual response to a defined treatment. To our best knowledge and to date, there is no test available to predict the response of a patient to dacarbazine. We show here that examination of melanoma histological sections by infrared micro-spectroscopy reveals the sensitivity of the cancer to dacarbazine. Unsupervised analysis of the FTIR spectra evidences spontaneous and significant clustering of infrared spectra into two groups that match the clinical responsiveness of the patients to dacarbazine used as a first-line treatment. A supervised model resulted in 83% of the patient status (responder/non-responder) being correctly identified. The spectra revealed a key modification in the nature and quantity of lipids in the cells of both groups.

Phase II study of the immune-checkpoint inhibitor ipilimumab plus dacarbazine in Japanese patients with previously untreated, unresectable or metastatic melanoma

PURPOSE

Ipilimumab (IPI), a monoclonal antibody against immune-checkpoint receptor cytotoxic T lymphocyte antigen-4, is designed to enhance antitumor T cell function. IPI 10 mg/kg plus dacarbazine (DTIC) significantly improved overall survival in a phase 3 study involving predominantly Caucasian patients, with an adverse event (AE) profile similar to that of IPI monotherapy. We conducted a single-arm, phase 2 study to evaluate the safety and efficacy of IPI plus DTIC in Japanese patients.

METHODS

Previously untreated patients with unresectable stage III or IV melanoma received IPI 10 mg/kg plus DTIC 850 mg/m(2) every 3 weeks for four doses (q3w × 4), followed by DTIC q3w × 4 and then IPI every 12 weeks until disease progression or intolerable toxicity.

RESULTS

All 15 treated patients reported drug-related AEs, the most common of which were increases in alanine aminotransferase (n = 12, 80 %) and aspartate aminotransferase (n = 11, 73 %). Treatment-related serious AEs were reported in 11 (73 %) patients. Nine patients (60 %) discontinued treatment due to drug-related toxicities. Immune-related AEs (irAEs) were reported in 14 patients (93 %). The most frequent irAEs were liver (n = 12, 80 %) and skin (n = 10, 67 %) toxicities. Five deaths were reported; all were caused by progressive disease. Efficacy evaluation showed one complete response, one partial response and four patients with stable disease. Best overall response rate was 13 % (2/15), and the disease control rate was 40 % (6/15). The study was terminated early due to frequent, high-grade liver toxicities.

CONCLUSIONS

IPI 10 mg/kg plus DTIC 850 mg/m(2) was not considered tolerable in the Japanese patient population. ClinicalTrials.gov identifier: NCT01681212.

Adjusting for the Confounding Effects of Treatment Switching-The BREAK-3 Trial: Dabrafenib Versus Dacarbazine

BACKGROUND

Patients with previously untreated BRAF V600E mutation-positive melanoma in BREAK-3 showed a median overall survival (OS) of 18.2 months for dabrafenib versus 15.6 months for dacarbazine (hazard ratio [HR], 0.76; 95% confidence interval, 0.48-1.21). Because patients receiving dacarbazine were allowed to switch to dabrafenib at disease progression, we attempted to adjust for the confounding effects on OS.

MATERIALS AND METHODS

Rank preserving structural failure time models (RPSFTMs) and the iterative parameter estimation (IPE) algorithm were used. Two analyses, "treatment group" (assumes treatment effect could continue until death) and "on-treatment observed" (assumes treatment effect disappears with discontinuation), were used to test the assumptions around the durability of the treatment effect.

RESULTS

A total of 36 of 63 patients (57%) receiving dacarbazine switched to dabrafenib. The adjusted OS HRs ranged from 0.50 to 0.55, depending on the analysis. The RPSFTM and IPE "treatment group" and "on-treatment observed" analyses performed similarly well.

CONCLUSION

RPSFTM and IPE analyses resulted in point estimates for the OS HR that indicate a substantial increase in the treatment effect compared with the unadjusted OS HR of 0.76. The results are uncertain because of the assumptions associated with the adjustment methods. The confidence intervals continued to cross 1.00; thus, the adjusted estimates did not provide statistically significant evidence of a treatment benefit on survival. However, it is clear that a standard intention-to-treat analysis will be confounded in the presence of treatment switching-a reliance on unadjusted analyses could lead to inappropriate practice. Adjustment analyses provide useful additional information on the estimated treatment effects to inform decision making.

IMPLICATIONS FOR PRACTICE

Treatment switching is common in oncology trials, and the implications of this for the interpretation of the clinical effectiveness and cost-effectiveness of the novel treatment are important to consider. If patients who switch treatments benefit from the experimental treatment and a standard intention-to-treat analysis is conducted, the overall survival advantage associated with the new treatment could be underestimated. The present study applied established statistical methods to adjust for treatment switching in a trial that compared dabrafenib and dacarbazine for metastatic melanoma. The results showed that this led to a substantially increased estimate of the overall survival treatment effect associated with dabrafenib.

Evaluation of protective effect of amifostine on dacarbazine induced genotoxicity

Anticancer therapy with alkylating agents has been used for many years. Dacarbazine (DTIC) as an alkylating agent is used alone or in combination with other chemotherapy drugs. In order to inhibit the formation of secondary cancers resulting from chemotherapy with DTIC, preventional strategies is necessary. The present study was undertaken to evaluate the genoprotective effect of amifostine on the genotoxic effects of DTIC in cell culture condition. To determine the optimum genotoxic concentration of DTIC, HepG2 cells were incubated with various DTIC concentrations including 5, 10 and 20 μg/ml for 2 h and the genotoxic effects were evaluated by the comet assay. The result of this part of the study showed that incubation of HepG2 cells with DTIC at 5 μg/ml was sufficient to produce genotoxic effect. In order to determine the protective effects of amifostine on genotoxicity induced by DTIC, HepG2 cells were incubated with different concentrations of amifostine (2, 3 and 5 mg/ml) for 1 h which was followed by incubation with DTIC at 5 μg/ml for 2 h. One hour incubation of cells with different concentrations of amifostine before incubation with DITC indicated that at least 5 mg/ml concentration of amifostine can prevent genotoxic effects induced by DTIC on HepG2 cells under described condition. In conclusion amifostine could prevent DNA damage induced by DTIC on HepG2 cells.

Role of MGMT as biomarker in colorectal cancer

O⁶-methylguanine DNA methyltransferase (MGMT) gene promoter methylation plays an important role in colorectal carcinogenesis, occurring in about 30%-40% of metastatic colorectal cancer. Its prognostic role has not been defined yet, but loss of expression of MGMT, which is secondary to gene promoter methylation, results in an interesting high response to alkylating agents such as dacarbazine and temozolomide. In a phase 2 study on heavily pre-treated patients with MGMT methylated metastatic colorectal cancer, temozolomide achieved about 30% of disease control rate. Activating mutations of RAS or BRAF genes as well as mismatch repair deficiency may represent mechanisms of resistance to alkylating agents, but a dose-dense schedule of temozolomide may potentially restore sensitivity in RAS-mutant patients. Further development of temozolomide in MGMT methylated colorectal cancer includes investigation of synergic combinations with other agents such as fluoropyrimidines and research for additional biomarkers, in order to better define the role of temozolomide in the treatment of individual patients.