Bosutinib versus imatinib in newly diagnosed chronic-phase chronic myeloid leukaemia: results from the 24-month follow-up of the BELA trial.

Bosutinib is an oral, dual SRC/ABL1 tyrosine kinase inhibitor for resistant/intolerant chronic myeloid leukaemia (CML). We assessed the efficacy and safety of bosutinib 500 mg/d (n = 250) versus imatinib 400 mg/d (n = 252) after >24 months from accrual completion in newly diagnosed chronic phase (CP)-CML (Bosutinib Efficacy and Safety in Newly Diagnosed CML trial [BELA]). Cumulative complete cytogenetic response (CCyR) rates by 24 months were similar (bosutinib, 79%; imatinib, 80%); cumulative major molecular response (MMR) rates were 59% for bosutinib and 49% for imatinib. Responses were durable; 151/197 vs. 172/204 and 125/153 vs. 117/131 responders remained on treatment and maintained CCyR and MMR, respectively. Since the 12-month primary analysis, no new accelerated-/blast-phase transformations occurred with bosutinib; four occurred with imatinib. Early response (BCR-ABL1/ABL1 ≤ 10%, 3 months) was associated with better CCyR and MMR rates by 12 and 24 months (both arms). Gastrointestinal events and liver function test elevations were more common, and neutropenia, musculoskeletal events and oedema were less common with bosutinib. Discontinuations due to adverse events were more common with bosutinib versus imatinib (most commonly alanine aminotransferase elevation: 4% vs. <1%); most occurred within the first 12 months. Cardiovascular adverse events were similar in both arms. Bosutinib continues to demonstrate good efficacy and manageable tolerability in newly diagnosed CP-CML patients.

Outcomes following hematopoietic stem cell transplantation in patients treated with standard chemotherapy with or without gemtuzumab ozogamicin for acute myeloid leukemia.

The phase 3 ALFA-0701 trial demonstrated improved outcomes with fractionated-dose gemtuzumab ozogamicin (GO) combined with standard chemotherapy vs. standard chemotherapy alone in adults with de novo acute myeloid leukemia (AML). We examined post-transplant outcomes and occurrence of hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) in patients who received hematopoietic stem cell transplantation (HSCT) as follow-up therapy in ALFA-0701. Patients aged 50-70 years were randomized to standard chemotherapy with or without GO (3 mg/m2 on days 1, 4, and 7 of induction and day 1 on each of two consolidation courses). Allogeneic HSCT was recommended for patients in first complete remission with matched (related or unrelated) donor, except those with core-binding factor AML or normal karyotype and either NPM1+/FLT3-ITDwt or CEBPA+ AML. Eighty-five patients (GO: n = 32; control: n = 53) received HSCT in first complete remission or after relapse/primary induction failure. Three patients (GO: n = 2; control: n = 1 [received GO as follow-up therapy]) developed VOD/SOS after HSCT or conditioning. Post-transplant survival, non-relapse mortality, and relapse were not different between arms. Results indicate fractionated-dose GO as part of induction and consolidation chemotherapy for AML does not induce excess post-transplant VOD/SOS or mortality and thus does not preclude the use of HSCT as consolidation treatment.

Intralysosomal cystine accumulation in mice lacking cystinosin, the protein defective in cystinosis.

Cystinosis is an autosomal recessive disorder characterized by an accumulation of intralysosomal cystine. The causative gene, CTNS, encodes cystinosin, a seven-transmembrane-domain protein, which we recently showed to be a lysosomal cystine transporter. The most severe and frequent form of cystinosis, the infantile form, appears around 6 to 12 months, with a proximal tubulopathy (de Toni-Debré-Fanconi syndrome) and ocular damage. End-stage renal failure is reached by 10 years of age. Accumulation of cystine in all tissues eventually leads to multisystemic disease. Treatment with cysteamine, which reduces the concentration of intracellular cystine, delays disease progression but has undesirable side effects. We report the first Ctns knockout mouse model generated using a promoter trap approach. We replaced the last four Ctns exons by an internal ribosome entry site-betagal-neo cassette and showed that the truncated protein was mislocalized and nonfunctional. Ctns(-/-) mice accumulated cystine in all organs tested, and cystine crystals, pathognomonic of cystinosis, were observed. Ctns(-/-) mice developed ocular changes similar to those observed in affected individuals, bone defects and behavioral anomalies. Interestingly, Ctns(-/-) mice did not develop signs of a proximal tubulopathy, or renal failure. A preliminary therapeutic trial using an oral administration of cysteamine was carried out and demonstrated the efficiency of this treatment for cystine clearance in Ctns(-/-) mice. This animal model will prove an invaluable and unique tool for testing emerging therapeutics for cystinosis.

Prosaposin gene expression in normal and dystrophic RCS rat retina.

PURPOSE: To identify proteins secreted by the retinal pigment epithelium (RPE) and to analyze their cellular distribution in normal and pathologic rat retinas at various stages of eye development. METHODS: A cDNA library was constructed with RNA isolated from porcine RPE sheets and screened by using the yeast signal sequence trap system. In situ hybridization, immunohistochemistry, and semiquantitative RT-PCR analysis were performed on rat retinas. RESULTS: The cDNA encoding prosaposin was isolated. This is the first time this gene has been shown to be expressed in the retina. Prosaposin mRNA was detected in the rat RPE cell monolayer and in ganglion cells 14, 21, and 45 days after birth. The amount of prosaposin mRNA increased between days 14 and 45 after birth in normal retinas (rdy+), but not in the pathologic retinas (rdy-) of RCS rats. CONCLUSIONS: Several techniques were used to determine the localization of prosaposin in rat retinas. The increase in the amount of prosaposin mRNA in normal retinas coincided with the maturation of photoreceptor cells and the beginning of the phagocytosis process. In addition, the RCS rdy- RPE cells, characterized by the abrogation of the ingestion phase of the photoreceptor outer segments, are deficient in prosaposin expression.

VEGF and KDR gene expression during human embryonic and fetal eye development.

PURPOSE: It is important to understand the development of the normal retinal vascular system, because it may provide clues for understanding the mechanisms underlying the neovascularization associated with several retinopathies of infancy and adulthood. However, little is known about normal human ocular vascularization. VEGF is a key growth factor during vascular development and one of its receptors, KDR, plays a pivotal role in endothelial cell proliferation and differentiation. The purpose of this study was to analyze VEGF and KDR gene expression patterns during the development of the human eye during the embryonic and fetal stages. METHODS: The gene expression of VEGF and KDR was analyzed by in situ hybridization in 7-week-old embryos and in 10- and 18-week-old fetuses. In addition, we performed VEGF and KDR immunohistochemistry experiments on 18-week-old fetus tissue sections. RESULTS: These results clearly demonstrated that the levels of VEGF and KDR transcripts are correlated during the normal development of the ocular vasculature in humans. The complementarity between the patterns of VEGF and KDR during the early stages of development suggests that VEGF-KDR interactions play a major role in the formation and regression of the hyaloid vascular system (HVS) and in the development of the choriocapillaris. In later stages (i.e., 18-weeks-old fetuses), the expression of KDR seems to be linked to the development of the retinal vascular system. VEGF and KDR transcripts were unexpectedly detected in some nonvascular tissues-that is, in the cornea and in the retina before the development of the retinal vascular system. CONCLUSIONS: The expression of VEGF and KDR correlates highly with the normal ocular vascularization in humans, but VEGF may also be necessary for nonvascular retinal developmental functions, especially for the coordination of neural retinal development and the preliminary steps of the establishment of the definitive stable retinal vasculature.

The beta3 integrin gene is expressed at high levels in the major haematopoietic and lymphoid organs, vascular system, and skeleton during mouse embryo development.

Integrins are a family of cell surface molecules that mediate the attachment of cells to the extracellular matrix (ECM). These alphabeta heterodimers are involved in many biological processes. We used northern blotting and in situ hybridization to study the pattern of beta3 integrin gene expression during mouse embryogenesis. Northern blotting detected two species of beta3 mRNA from 7 to 17 days post coitum (dpc). These transcripts were abundant in the adult testis, kidney, liver, spleen, and heart. In situ hybridization experiments detected high levels of beta3 in the major haematopoietic and lymphoid organs: yolk sac, liver, and thymus. Moreover, beta3 transcripts were also detected in the vascular system, where beta3 integrin probably plays a key role in angiogenesis and vasculogenesis. We also detected a hybridization signal in the gut, the bronchioles of the lungs, and the bladder wall. beta3 transcripts were also present in the medullary regions of the adrenal glands and in the developing skeleton. Our study shows that beta3 gene expression is not restricted to the liver and gut during mouse development. We also detected beta3 integrin mRNA in the yolk sac, vessels, lung, bladder, and developing bones. Our data suggest that beta3 integrin plays a key role in many important physiological processes like haematopoiesis, angiogenesis, phagocytosis, and bone resorption.

Bosutinib versus imatinib in newly diagnosed chronic-phase chronic myeloid leukemia: results from the BELA trial.

PURPOSE: Bosutinib is an oral Src/Abl tyrosine kinase inhibitor. The phase III Bosutinib Efficacy and Safety in Newly Diagnosed Chronic Myeloid Leukemia (BELA) trial compared bosutinib with imatinib in newly diagnosed, chronic-phase chronic myeloid leukemia (CML). PATIENTS AND METHODS: A total of 502 patients were randomly assigned 1:1 to bosutinib 500 mg per day or imatinib 400 mg per day. RESULTS: The complete cytogenetic response (CCyR) rate at 12 months was not different for bosutinib (70%; 95% CI, 64% to 76%) versus imatinib (68%; 95% CI, 62% to 74%; two-sided P = .601); therefore, the study did not achieve its primary end point. The major molecular response (MMR) rate at 12 months was higher with bosutinib (41%; 95% CI, 35% to 47%) compared with imatinib (27%; 95% CI, 22% to 33%; two-sided P < .001). Time to CCyR and MMR was faster with bosutinib compared with imatinib (two-sided P < .001 for both). On-treatment transformation to accelerated/blast phase occurred in four patients (2%) on bosutinib compared with 10 patients (4%) on imatinib. A total of three CML-related deaths occurred on the bosutinib arm compared with eight on the imatinib arm. The safety profiles of bosutinib and imatinib were distinct; GI and liver-related events were more frequent with bosutinib, whereas neutropenia, musculoskeletal disorders, and edema were more frequent with imatinib. CONCLUSION: This ongoing trial did not meet its primary end point of CCyR at 12 months, despite the observed higher MMR rate at 12 months, faster times to CCyR and MMR, fewer on-treatment transformations to accelerated/blast phase, and fewer CML-related deaths with bosutinib compared with imatinib. Each drug had a distinct safety profile.