Nilotinib in chronic myeloid leukemia patients in chronic phase (CML-CP) with imatinib (IM) resistance or intolerance: Longer follow-up results of a phase II study

7029

Background: Nilotinib is a potent and highly selective BCR-ABL inhibitor approved for the treatment of Ph+ CML patients (pts) in CP or accelerated phase who are resistant or intolerant to prior therapy including IM. This study evaluated the efficacy and safety of nilotinib (400 mg bid) in CML-CP pts resistant or intolerant to IM. Methods: Primary endpoint was major cytogenetic response (MCyR). Secondary endpoints included complete cytogenetic response (CCyR), complete hematological response (CHR), MCyR duration, overall survival (OS), and safety. Results: CML-CP pts (n = 321, 70% IM-resistant, 30% IM-intolerant with resistance) with a minimum follow-up of 19 months (mos) were evaluated; 72% were treated with ≥600 mg/day IM prior to enrollment. Median duration of prior IM treatment was 32 (<1–94) mos. Median dose intensity of nilotinib (790 mg/day; range 151–1,110 mg/day) closely approximated the planned dose. Nilotinib led to rapid and durable CHR and MCyR. CHR was observed in 94% of pts. 59% achieved an MCyR (2.8 mos median time to MCyR; 56% in IM-resistant, and 65% in IM-intolerant pts), including 73% of pts with a baseline CHR and 44% achieved a CCyR (41% in IM-resistant; 51% in IM-intolerant pts). Responses were durable, with 78% pts maintaining MCyR at 24 mos. Estimated OS rate was 88% at 24 mos. Safety profile did not change with longer follow-up. Most frequent grade (gr) 3/4 biochemical laboratory abnormalities were elevated lipase (17%), hypophosphataemia (16%), hyperglycemia (12%), and total bilirubin (8%) which were transient and clinically asymptomatic. Gr 3/4 non-hematologic AEs were infrequent: rash, headache, and diarrhea occurred in 2% of pts. Most common gr 3/4 hematological laboratory abnormalities were neutropenia (31%), thrombocytopenia (31%), and anemia (10%). Brief dose interruptions were successful in management of most AEs. Pleural or pericardial effusions (gr 3/4) were uncommon (< 1%). Conclusions: These results demonstrate that nilotinib was highly effective, with rapid and durable responses in CML-CP pts failing prior therapy due to resistance or intolerance. Nilotinib was well tolerated with favorable risk/benefit.

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Effect of nilotinib on the pharmacokinetics and pharmacodynamics of warfarin

7063

Background: Nilotinib, a highly selective and potent BCR-ABL tyrosine kinase inhibitor, is approved for the treatment of CML-CP and CML-AP in patients resistant or intolerant to prior therapy including imatinib. Nilotinib has shown competitive inhibition of CYP2C9 in vitro, but its effect on CYP2C9 activity in human is unknown. This study evaluated the effects of nilotinib on the pharmacokinetics (PK) and pharmacodynamics (PD) of warfarin, a sensitive CYP2C9 substrate, in healthy subjects. Methods: Twenty-four subjects (6F, 18M, age 21–65 years) were enrolled to receive a single oral 25 mg warfarin with either 800 mg nilotinib or matching placebo (administered 30 minutes after consumption of a high-fat meal) in a cross-over design. Serial blood samples were collected post-dose for determining nilotinib, S- and R-warfarin concentrations. Prothrombin time (PT) and international normalized ratio (INR) were determined as PD measures for warfarin. CYP2C9 genotyping was performed in all subjects using TaqMan assay. Results: Sixteen subjects were identified as CYP2C9 extensive metabolizers (EM) and 8 as intermediate metabolizers (IM), but none was poor metabolizer. PK parameters of S- and R-warfarin were found to be similar between two treatments (warfarin + nilotinib versus warfarin alone) for both EM and IM groups. The geometric mean ratios (90% CIs) for the Cmax and AUC0-∞ of S-warfarin in all subjects were 0.98 (0.95–1.02) and 1.03 (0.99–1.07), respectively, and for R-warfarin were 1.00 (0.96–1.04) and 1.02 (0.99–1.06) respectively. Mean ratios for the maximum value and AUC of PT were 1.00 (0.96–1.04) and 1.00 (0.98–1.02), respectively, and for INR were 1.00 (0.97–1.01) and 1.00 (0.99–1.01), respectively. Nilotinib Cmax was 1872±560 ng/mL, which is comparable to the mean steady-state Cmax in CML and GIST patients receiving 400 mg BID doses. Adverse effects observed following either treatment were generally consistent with the known safety profiles of both drugs, and there were no new safety issues observed. Conclusion: The study results demonstrate a lack of effect of nilotinib on the PK and PD of warfarin, suggesting nilotinib does not inhibit CYP2C9 activity in human subjects. These findings suggest that warfarin can be used with nilotinib concurrently without the risk of bleeding.

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Nilotinib in chronic myeloid leukemia patients in accelerated phase (CML-AP) with imatinib (IM) resistance or intolerance: Longer follow-up results of a phase II study

7057

Background: Nilotinib is a potent and highly selective BCR-ABL inhibitor approved for the treatment of Ph+ CML patients (pts) in chronic phase or AP who are resistant or intolerant to prior therapy including IM. This study evaluated the efficacy and safety of nilotinib (400 mg bid) in CML-AP pts resistant or intolerant to IM. Methods: Primary endpoint was confirmed hematologic response (HR). Secondary endpoints included major cytogenetic response (MCyR), time to progression, overall survival (OS), and safety. Results: 137 CML-AP pts (80% IM-resistant; 20% IM-intolerant with resistance) with minimum follow-up of 11 months (mos) (median age, 57 years; median duration of prior IM treatment, 28 mos) were included. IM-intolerant pts were also IM-resistant and without MCyR at study entry. 79% pts had prior IM ≥600 mg/day. Median dose intensity of nilotinib was 775 mg/day and median duration of exposure was 272 days. 56% had confirmed HR and 31% had complete hematologic response (CHR). 30% of IM-resistant and 37% of IM-intolerant pts achieved CHR. Responses were rapid, with a median time to first HR of 1 mo. HRs were durable at 24 mos with 54% of pts maintaining their response. MCyR was achieved in 32% of pts (30% in IM-resistant, 41% in IM-intolerant) and complete cytogenetic response in 20% of pts (18% in IM-resistant, 30% in IM-intolerant). Cytogenetic responses were also durable with 70% of pts maintaining MCyR at 24 mos; 83% of pts maintained CCyR at 12 mos. Estimated OS at 24 mos was 67%. Only 9% of pts discontinued therapy due to drug-related adverse events (AE). The most frequently reported grade 3/4 laboratory abnormalities were thrombocytopenia (41%), neutropenia (42%), anemia (25%), elevated serum lipase (18%), and hypophosphatemia (14%). The rates of grade 3/4 myelosuppression were low, predictable, and easily managed with median onset of 14 to 29 days and median duration of 8 to 26 days. Grade 3/4 non-hematologic AEs were rare (< 1%) and included nausea, fatigue, and diarrhea. Conclusions: These long-term follow-up results confirm that nilotinib induces rapid and durable responses in CML-AP pts who failed prior IM due to intolerance or resistance, with a favorable risk/benefit.

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Effect of the proton pump inhibitor esomeprazole on the oral absorption and pharmacokinetics of nilotinib

7053

Background: Nilotinib, a highly selective and potent BCR-ABL tyrosine kinase inhibitor, is approved for the treatment of CML-CP and CML-AP patients resistant or intolerant to prior therapy including imatinib. The solubility of nilotinib is pH dependent, with lower solubility at higher pH. We evaluated whether esomeprazole, a potent proton pump inhibitor (PPI) that can significantly increase gastric pH, could affect the oral absorption and pharmacokinetics of nilotinib in healthy subjects. Methods: Twenty-two subjects (6 F, 16M, age range 18–64 years) were enrolled to receive nilotinib alone or in the presence of steady-state esomeprazole during two treatment periods. Nilotinib was given as a single oral 400 mg dose on days 1 and 13, and esomeprazole 40 mg once-daily on day 8 through day 13. Serial blood samples were collected up to 72 hours after nilotinib dosing for determination of nilotinib serum concentrations by a validated liquid chromatography-tandem mass spectrometry assay. Gastric pH was monitored in all subjects at baseline (prior to nilotinib and esomeprazole dosing), before and during the first 4 hrs of esomeprazole steady state dosing (fifth dose on Day 12). Results: When coadministered with esomeprazole, nilotinib Cmax was decreased by 27% (397±89 vs 303±157ng/mL) and AUC0-∞ decreased by 34% (11515±6140 vs 7164±3752ng*hr/mL) respectively. The median time to reach nilotinib Cmax was slightly prolonged from 4.0 hrs to 6.0 hrs, but its elimination half-life was not altered (17.3±10.7 vs 15.9±6.6 hrs). Median gastric pH was increased from 0.8 at baseline to 2.0 at pre-dose, and to 3.9, 5.8, 5.5, and 5.7 at 1, 2, 3, and 4 hrs after esomeprazole dosing. Administration of nilotinib alone or in combination with esomeprazole was generally well tolerated in the study subjects. Conclusions: The study results demonstrate a modest reduction in the rate and extent of nilotinib absorption when co-administered with esomeprazole. Such an effect is unlikely to cause a significant clinical consequence for nilotinib therapy, and thus nilotinib can be used with esomeprazole or other PPIs without the risk of substantial decrease in nilotinib systemic exposure.

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CD40 activation in epithelial ovarian carcinoma cells modulates growth, apoptosis, and cytokine secretion

BACKGROUND/AIMS

CD40, a member of the tumour necrosis factor (TNF) receptor family, is expressed on a variety of haematopoietic cells and is crucial in orchestrating both humoral and cellular immune responses. CD40 is also expressed on some carcinoma cells, where its function remains largely unknown. This study investigated the effects of CD40 ligation on ovarian carcinoma cell growth and apoptosis and on cytokine production, in addition to the role of the NF-kappa B and JNK signalling pathways.

METHODS

CD40 expression was measured in epithelial ovarian carcinoma (EOC) biopsies by immunohistochemistry and in EOC cell lines by flow cytometry. To examine the effects of CD40 ligation on cell growth recombinant soluble CD40 ligand was used to stimulate EOC cell lines and growth was measured by MMT assays. Cytokine production was measured by enzyme linked immunosorbent assays interleukin 8 (IL-8) gene transcription was estimated by means of reverse transcription polymerase chain reaction. The integrity of the CD40 signalling pathway in those cell lines that did not produce cytokines in response to CD40 ligation was assessed by the detection of the transcription factor NF-kappa B by an electrophoretic mobility shift assay. To investigate the defect in the NF-kappa B pathway the phosphorylation status of I kappa B alpha was determined by an antibody specific to phosphorylated I kappa B alpha and dissociation of the I kappa B alpha-p65 complex was assessed by co-immunoprecipitation.

RESULTS

CD40 is expressed in primary ovarian carcinoma biopsies and EOC cell lines. CD40 ligation resulted in growth inhibition in most of these carcinoma cell lines and was also found to promote apoptosis, with this last effect only being evident in early passage EOC cells. CD40 ligation also induced significant IL-6 and IL-8 production in most of the EOC cell lines examined and it was confirmed for IL-8 that this effect was regulated at the transcriptional level. NF-kappa B activation in response to CD40 ligation was found in three of the EOC cell lines and specific defects in the CD40 induced NF-kappa B pathway were identified in two cell lines. However, CD40 engagement induced JNK activation in all the EOC cell lines.

CONCLUSIONS

These data suggest that the CD40 pathway is functional in ovarian carcinoma cells and highlight the need for further studies to provide insight into the role of CD40 in the carcinogenic process and the possible exploitation of this pathway for novel therapeutic approaches.

CD40 induces apoptosis in carcinoma cells through activation of cytotoxic ligands of the tumor necrosis factor superfamily

CD40, a tumor necrosis factor (TNF) receptor (TNFR) family member, conveys signals regulating diverse cellular responses, ranging from proliferation and differentiation to growth suppression and cell death. The ability of CD40 to mediate apoptosis in carcinoma cells is intriguing given the fact that the CD40 cytoplasmic C terminus lacks a death domain homology with the cytotoxic members of the TNFR superfamily, such as Fas, TNFR1, and TNF-related apoptosis-inducing ligand (TRAIL) receptors. In this study, we have probed the mechanism by which CD40 transduces death signals. Using a trimeric recombinant soluble CD40 ligand to activate CD40, we have found that this phenomenon critically depends on the membrane proximal domain (amino acids 216 to 239) but not the TNFR-associated factor-interacting PXQXT motif in the CD40 cytoplasmic tail. CD40-mediated cytotoxicity is blocked by caspase inhibitors, such as zVAD-fmk and crmA, and involves activation of caspase 8 and caspase 3. Interestingly, CD40 ligation was found to induce functional Fas ligand, TRAIL (Apo-2L) and TNF in apoptosis-susceptible carcinoma cells and to up-regulate expression of Fas. These findings identify a novel proapoptotic mechanism which is induced by CD40 in carcinoma cells and depends on the endogenous production of cytotoxic cytokines and autocrine or paracrine induction of cell death.

Activation of the p38 mitogen-activated protein kinase pathway by Epstein-Barr virus-encoded latent membrane protein 1 coregulates interleukin-6 and interleukin-8 production

The Epstein-Barr virus-encoded latent membrane protein 1 (LMP1) is a pleiotropic protein the activities of which include effects on gene expression and cell transformation, growth, and death. LMP1 has been shown to induce nuclear factor (NF)-kappaB and c-Jun NH2-terminal kinase/AP-1 activities in target cells, and in this study we demonstrate that LMP1 also engages the p38 mitogen-activated protein kinase cascade, leading to activation of the transcription factor ATF2. Mutational analysis of the LMP1 cytoplasmic COOH terminus revealed that p38 activation occurs from both the tumor necrosis factor receptor-associated factor (TRAF)-interacting, membrane-proximal COOH-terminal activating region (CTAR)1 domain (amino acids 186-231) and the extreme tumor necrosis factor receptor-associated death domain (TRADD) binding CTAR2 region (amino acids 351-386). Because LMP1 also engages signaling on the NF-kappaB axis through CTAR1 and CTAR2, we have examined whether these two pathways are overlapping or independent. We have found that inhibition of p38 by the highly specific inhibitor SB203580 did not affect NF-kappaB binding activity. Conversely, although the metabolic inhibitor D609 blocked NF-kappaB activation, it did not impair the ability of LMP1 to signal on the p38 axis, suggesting that these two LMP1-mediated pathways are primarily independent. Divergence of signals must, however, occur downstream of TRAF2 as a dominant negative TRAF2 mutant that blocks LMP1-induced NF-kappaB activation also inhibited p38 signaling. In addition, we have found that p38 inhibition significantly impaired LMP1-mediated interleukin-6 and -8 expression. Thus, p38 may play a significant cooperative role in regulating at least some of the pleiotropic activities of LMP1.

CD40 and epithelial cells: across the great divide

The widespread expression of CD40 in normal epithelial cells and carcinoma cells suggests that this receptor has important, additional influences beyond that of regulating immune responses. Here, Lawrence Young and colleagues discuss the effect of CD40 ligation on epithelial cells and consider the role of this pathway in the pathogenesis and treatment of carcinomas.