Phase II study of pembrolizumab and lenvatinib in advanced well-differentiated neuroendocrine tumors.

BACKGROUND: Immune checkpoint inhibitors (CPIs) have not been shown to be active in well-differentiated neuroendocrine tumors (NETs), with response rates <5%. Lenvatinib is a multitargeted tyrosine kinase inhibitor which binds to vascular endothelial growth factor and fibroblast growth factor receptors and has demonstrated efficacy in pancreatic and gastrointestinal NETs [44% and 16% objective radiographic response rate (ORR), respectively]. The combination of antiangiogenic and CPI therapies can be synergistic. We therefore evaluated the combination of lenvatinib and pembrolizumab in well-differentiated gastrointestinal (GI) and thoracic NETs. PATIENTS AND METHODS: A prospective, phase II trial evaluated patients with advanced GI/thoracic NETs (pancreatic NETs were excluded due to high response rate of lenvatinib monotherapy in this patient population), with evidence of progression within 8 months of study entry and at least two prior lines of systemic therapy. Patients received lenvatinib 20 mg daily and pembrolizumab 200 mg intravenously every 3 weeks until unacceptable toxicity or progression of disease. Primary endpoint was objective response rate, and an interim analysis was planned once 20 patients were enrolled. Four ORRs were required to continue enrollment. RESULTS: Twenty patients were enrolled on protocol from April 2021 to January 2022 (nine small intestine, five lung, two thymic, two unknown primary, one cecal, one presacral primaries). Two patients (10%) achieved a partial response (atypical lung and small intestinal primaries). Median progression-free survival (PFS) was 8 months (95% confidence interval 5.8-10.2 months). Twelve (60%) patients experienced probably or definitely associated grade 3 adverse events (10 hypertension). Fourteen patients (70%) required dose reductions or discontinued one of the medications. Two patients discontinued treatment before radiographic assessment. CONCLUSIONS: The combination of pembrolizumab and lenvatinib did not show sufficient response in patients with NETs to warrant continued enrollment on trial.

A phase II clinical trial of sunitinib following hepatic transarterial embolization for metastatic neuroendocrine tumors.

BACKGROUND: The liver is the predominant site of metastases among patients with advanced neuroendocrine tumors (NETs). Prior retrospective studies have reported high response rates in patients treated with transarterial embolization (TAE). NETs are highly vascular and are known to express vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor (VEGFR). We hypothesized that administration of sunitinib, a VEGFR inhibitor, following TAE would extend progression-free survival (PFS). PATIENTS AND METHODS: Patients with metastatic NETs to the liver underwent a series of selective TAEs followed by sunitinib (until disease progression or maximum of 12 months). Radiographic response (by RECIST), survival, and safety parameters were monitored. RESULTS: Thirty-nine patients were enrolled. The overall response rate was 72% [95% confidence interval (CI), 0.58-0.86]. Median PFS was 15.2 months. Rates of overall survival (OS) at 1 and 4 years were 95% (95% CI, 0.88-1.00) and 59% (95% CI, 0.38-0.80), respectively. A significant 34% rise in serum VEGF was observed following the initial TAE (P = 0.03). CONCLUSIONS: Hepatic TAE is a highly active treatment option for patients with metastatic NETs to the liver. Embolization stimulates release of VEGF into the circulation. Sunitinib, an oral VEGFR inhibitor, can be safely administered following embolization. The high rates of PFS and OS associated with this sequence of therapies are encouraging.

5'nucleotidase is sorted to the apical domain of hepatocytes via an indirect route.

In hepatocytes, all newly synthesized plasma membrane (PM) proteins so far studied arrive first at the basolateral domain; apically destined proteins are subsequently endocytosed and sorted to the apical domain via transcytosis. A mechanism for the sorting of newly synthesized glycophosphatidylinositol (GPI)-linked proteins has been proposed whereby they associate in lipid microdomains in the trans-Golgi network and then arrive at the apical domain directly. Such a mechanism poses a potential exception to the hepatocyte rule. We have used pulse-chase techniques in conjunction with subcellular fractionation to compare the trafficking of 5' nucleotidase (5NT), an endogenous GPI-anchored protein of hepatocytes, with two transmembrane proteins. Using a one-step fractionation technique to separate a highly enriched fraction of Golgi-derived membranes from ER and PM, we find that both 5NT and the polymeric IgA receptor (pIgAR) traverse the ER and Golgi apparatus with high efficiency. Using a method that resolves PM vesicles derived from the apical and basolateral domains, we find that 5NT first appears at the basolateral domain as early as 30 min of chase. However the subsequent redistribution to the apical domain requires > 3.5 h of chase to reach steady state. This rate of transcytosis is much slower than that observed for dipeptidylpeptidase IV, an apical protein anchored via a single transmembrane domain. We propose that the slow rate of transcytosis is related to the fact that GPI-linked proteins are excluded from clathrin-coated pits/vesicles, and instead must be endocytosed via a slower nonclathrin pathway.

Characterization of elementary Ca2+ release signals in NGF-differentiated PC12 cells and hippocampal neurons.

Elementary Ca2+ release signals in nerve growth factor- (NGF-) differentiated PC12 cells and hippocampal neurons, functionally analogous to the "Ca2+ sparks" and "Ca2+ puffs" identified in other cell types, were characterized by confocal microscopy. They either occurred spontaneously or could be activated by caffeine and metabotropic agonists. The release events were dissimilar to the sparks and puffs described so far, as many arose from clusters of both ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (InsP3Rs). Increasing either the stimulus strength or loading of the intracellular stores enhanced the frequency of and coupling between elementary release sites and evoked global Ca2+ signals. In the PC12 cells, the elementary Ca2+ release preferentially occurred around the branch points. Spatio-temporal recruitment of such elementary release events may regulate neuronal activities.

A method of predicting adult height and obesity in long-term survivors of childhood acute lymphoblastic leukemia.

PURPOSE: Short stature and obesity have been reported among long-term survivors of childhood acute lymphocytic leukemia (ALL). We examined factors that contribute to these adverse sequelae. PATIENTS AND METHODS: Serial height and weight measurements were analyzed for 91 long-term survivors who were treated for ALL between 1967 and 1975 at a single institution. These patients were all younger than 12 years at diagnosis, were in continuous complete remission, had reached final height, and had height and weight measurements within 1 year of age 18 years. They had received craniospinal (n = 33) or cranial irradiation (n = 58) to total doses of 24 Gy as CNS prophylaxis. Standard deviation scores (SDS) were used to reflect the deviation of height and weight measurements from population means, and the body mass index (BMI; weight divided by height squared) was used in assessing obesity at age 18 years. RESULTS: Short stature (less than fifth percentile) was seen in 41 patients (45%), and obesity (BMI greater than or equal to 24 kg/m2) in 35 (38%). Regression formulae were developed that explain 65% and 62% of the variability in patient height and BMI, respectively. CONCLUSIONS: Risk factors were identified for abnormally short stature, which was defined to be a decrease of 1.5 SDS in height from diagnosis to age 18 years. These factors include younger age and above-average height for age at diagnosis (height SDS greater than 0), craniospinal irradiation, and greater decrease in height SDS during antileukemic therapy. Risk factors for obesity at age 18 years include weight SDS greater than 0 and greater than height SDS at 1 year after the end of chemotherapy.

Acute nonlymphoblastic leukemia in infants: clinical presentation and outcome.

The presenting features and clinical outcome of acute nonlymphoblastic leukemia (ANLL) in infants and older children were compared to identify any differences that might suggest methods to improve therapy. Twelve of the 29 infants were boys and 17 were girls, with ages ranging from two days to 12 months (median, 7 months). By comparison with 222 patients greater than 1 year of age, infants were significantly more likely to have monoblastic or myelomonoblastic leukemia (P less than .0001), chloroma (P less than .0001), marked hepatomegaly (P = .001), and high leukocyte count (P = .005) and were less likely to have Auer rods (P less than .001). Each of these features except leukocyte count showed an association with infant ANLL in a multivariate analysis. Twenty-four (83%) of the infants attained a complete remission, a rate that was not significantly different from that of the older children. Even though infants had a significantly higher CNS relapse rate (P = .003), their event-free survival times were no different than those of older children (P = .74). Ten of the infants remain in initial complete remission for 5+ to 112+ months (median, 52+ months). Infants with ANLL did not have a poorer prognosis than older patients in our study; future protocols for this age group should emphasize more effective systemic therapy, preferably including an epipodophyllotoxin, as well as improved treatment for subclinical CNS leukemia.

Adrenocortical carcinoma in children: a study of 40 cases.

Adrenocortical carcinoma (ACC), a very rare tumor in children in the United States, is apparently more common among Brazilian children. We reviewed the medical records of 40 children whose disease was diagnosed between 1966 and 1987. There were 12 boys and 28 girls; their median age was 3.9 years (range, 1 day to 15.7 years). Virilization was the most common clinical sign (37 of 40); other signs included abdominal mass, deepened voice, plethora, hypertension, seizures (seven patients) and, rarely, weight loss (two patients). The median time between first signs or symptoms and diagnosis was 1.4 years (range, 3 days to 5 years). Four of 33 tumors were classified as benign according to the Weiss, van Slooten, or Hough systems (tumor tissue was unavailable for seven patients). Tumors were completely resected in 26 of 38 patients; of those, 17 are in continuous complete remission, five relapsed, and four have been lost to follow-up. One patient, who had local recurrence, has been in a third complete remission for 18+ months after tumor resection and chemotherapy (cisplatin and etoposide). Of the remaining 14 patients, 11 died of progressive disease, the diagnosis was confirmed at autopsy in two, and one has been lost to follow-up. Univariate analysis disclosed that age greater than or equal to 3.5 years at diagnosis, interval of greater than or equal to 6 months between first symptoms and diagnosis, tumor weight greater than 100 g, tumor size greater than 200 cm3, and high levels of urinary 17-ketosteroids (17-KS) and 17-hydroxycorticosteroids (17-OH) were associated with an unfavorable outcome. Multivariate analysis disclosed that only a tumor size greater than 200 cm3 independently identifies those patients with an unfavorable prognosis. Among the variables known before surgery, age, and the interval between first symptoms and diagnosis were important predictors of outcome. Our data suggest that some children with ACC and certain clinical characteristics are at high risk of primary treatment failure and, therefore, are good candidates for investigational adjuvant therapy.

Abnormal growth patterns and adult short stature in 115 long-term survivors of childhood leukemia.

Significant growth retardation was found in 115 survivors of childhood acute lymphoblastic leukemia (ALL) who had completed their growth. These children were diagnosed before 12 years of age and treated on four protocols in a single institution; all received either cranial (n = 78) or craniospinal (n = 37) prophylactic irradiation. Patients' heights at diagnosis were within expected ranges, but final heights were greater than or equal to 1 SD below population means in 74% of cases and greater than or equal to 2 SD in 37%. Effects on growth were more pronounced for children who had received craniospinal irradiation, but decrements were also significant in the cranial irradiation group, with adult heights greater than or equal to 2 SD below population norms in 32%. Growth retardation was significantly greater (P less than .0001) in children who had earlier disease onset. Growth deceleration occurred not only during chemotherapy but during a later period that followed an interval of improved growth in many cases. Thus, late decrements in growth may be missed in studies that do not follow patients until they have attained final heights. These findings indicate that abnormally short stature among survivors of ALL merits further clinical and research attention.

2-Chlorodeoxyadenosine produces a high rate of complete hematologic remission in relapsed acute myeloid leukemia.

PURPOSE: The purine analog 2-chlorodeoxyadenosine (2-CDA) was well tolerated and showed promising anti-leukemic activity in a phase I trial conducted at St Jude Children's Research Hospital. To substantiate and extend this result, we performed a phase II trial in a representative group of children and young adults with relapsed acute leukemia. PATIENTS AND METHODS: Twenty-four patients (median age, 11 years) with acute myeloid or lymphoid leukemia in first or later relapse (acute myeloid leukemia [AML], 17; acute lymphoid leukemia [ALL], seven) were given continuous infusion 2-CDA for 5 days at 8.9 mg/m2/d. Patients with residual blast cells 10 days after treatment received a second course of 2-CDA that was identical to the first. Detailed pharmacokinetic studies were performed on plasma collected from five patients. RESULTS: Eight (47%) of the 17 patients with AML had complete hematologic remissions (four after the initial course of 2-CDA), and two (12%) had partial remissions, for a total response rate of 59%. Only one child with ALL achieved remission. Seven of the responding patients underwent allogeneic or autologous bone marrow transplantation, with six remaining free of leukemia for a median of 7 months (range, 1 to 11 months). The major form of drug-induced toxicity was hematologic, with severe neutropenia and thrombocytopenia (National Cancer Institute [NCI] grade 3 or 4) developing in 34 of the 36 courses of 2-CDA. In responding patients, the median times to recovery of neutrophil counts greater than 0.5 x 10(9)/L and platelet counts greater than 50 x 10(9)/L were 18 and 21 days, respectively. There were no deaths due to toxicity. The mean steady-state plasma concentration of 2-CDA was 34.6 nmol/L (range, 20 to 54 nmol/L). CONCLUSION: 2-CDA given by prolonged continuous infusion has clinically significant activity against AML and merits further testing in multidrug regimens for this disease.

Prognostic importance of cytogenetic subgroups in de novo pediatric acute nonlymphocytic leukemia.

Reports of close associations between recurring chromosomal abnormalities and the clinical behavior of acute nonlymphocytic leukemia (ANLL) have stimulated efforts to define this disease in cytogenetic terms. Here we report on the leukemic cell karyotypes of 155 children with ANLL who were treated from 1980 to 1987 in consecutive programs of chemotherapy at this institution. Of 121 cases with adequate banding, 20% were normal, 30% had miscellaneous clonal abnormalities, and 50% were classified into known cytogenetic subgroups: inv(16)/del(16q) (n = 15), t(8; 21) (n = 14), t(15;17) (n = 9), t(9;11) (n = 9), t(11;V)/del(11q) (n = 7) and -7/del(7q) (n = 6). The inv(16)/del(16q) cases showed a nearly equal distribution of myelocytic and monocytic French-American-British (FAB) subtypes; only four of these patients presented with M4Eo morphology. Despite a 100% remission induction rate, patients with inv(16)/del(16q)-positive ANLL fared no better overall than the entire group; only 40% of this subgroup were event-free survivors at 2 years from diagnosis (P = .23). Patients with inv(16)/del(16q) frequently had CNS involvement at diagnosis (eight of 15) or initially relapsed in this site (three of eight). Event-free survival (EFS) was clearly superior for young patients with FAB M5 leukemia and the t(9;11) (P = .041). These patients were clinically indistinguishable from others with the FAB disease subtype, yet their responses to etoposide-containing therapies were noteworthy. By contrast, children with structural abnormalities involving 11q23, other than t(9;11), were infants (median age, 6 months) with FAB M4 or M5 leukemia, hyperleukocytosis, and frequent coagulation abnormalities. Patients with such changes [t(11;V) or del(11q)] relapsed early during postremission therapy: none remained disease-free more than 16 months from diagnosis. Because of resistant leukemia, patients with monosomy 7/del(7q) had a poor remission induction rate (17%; P = .0015); patients with the t(15;17) were also poor responders to induction therapy (44%; P = 0.02) because of hemorrhagic deaths. These results identify several cytogenetic subtypes of pediatric ANLL that may represent unique disease processes for which more effective early cytoreduction [-7/del(7q), t(11;V)], better supportive care measures [t(15;17)], or more effective CNS prophylaxis [inv(16)/del(16q)] would be warranted.

Hearing loss in children and young adults receiving cisplatin with or without prior cranial irradiation.

One hundred seventy-seven children and young adults with various malignant neoplasms were prospectively tested for hearing loss after they had received cisplatin (n = 146), cranial irradiation (n = 18), or both (n = 13). Adequate renal function, no history of treatment with ototoxic drugs other than cisplatin, and availability for repeated audiometric testing were requirements for enrollment. Substantial hearing loss, defined as a hearing threshold of 50 dB or greater, was noted in only 11% of the cohort on tests conducted at the common speech frequencies (500 to 3,000 Hz). About half the patients had substantial deficits at higher frequencies (4,000 to 8,000 Hz). The probability of substantial hearing loss was directly related to the cumulative dose of cisplatin. In nonirradiated patients tested at the speech frequencies, there was a negligible risk of substantial deficits over the dose range of 90 to 360 mg/m2. As the dose increased to 720 mg/m2, the risk increased to 22%. In irradiated patients who later received cisplatin, cumulative drug doses as low as 270 mg/m2 were associated with a high probability of substantial hearing loss, suggesting potentiation of ototoxicity when these therapies are used together. Hearing acuity was either not affected or only minimally decreased in the irradiation-only group. Younger age, prior irradiation, and the presence of a CNS tumor each contributed significantly to the severity of hearing deficits at given cisplatin dose levels. We conclude that early increases in hearing threshold at a stimulus frequency of 4,000 Hz indicate probable subsequent deficits at lower frequencies, especially in young children with CNS tumors who have received cranial irradiation. The probability charts derived from this analysis should provide a useful tool for predicting hearing loss in the speech frequencies.

HER-2/neu amplification in benign breast disease and the risk of subsequent breast cancer.

PURPOSE: The purpose of this study was to determine whether the presence of HER-2/neu gene amplification and/or overexpression in benign breast disease was associated with an increased risk of subsequent breast cancer. PATIENTS AND METHODS: We conducted a nested case-control study of a cohort of women who were diagnosed with benign breast disease at the Mayo Clinic and who were subsequently observed for the development of breast cancer. Patients who developed breast cancer formed the case group, and a matched sample from the remaining cohort served as controls. Benign tissue samples from 137 cases and 156 controls and malignant tissues from 99 cases provided DNA or tissue for evaluation of HER-2/neu amplification and protein overexpression. RESULTS: Among the controls, seven benign tissues (4.5%) demonstrated low-level HER-2/neu amplification, whereas 13 benign (9.5%) and 18 malignant (18%) tissue specimens from cases exhibited amplification. HER-2/neu amplification in benign breast biopsies was associated with an increased risk of breast cancer (odds ratio ¿OR = 2.2; 95% confidence interval ¿CI, 0.9 to 5.8); this association approached statistical significance. The risks for breast cancer associated with benign breast histopathologic diagnoses were OR = 1.1 (95% CI, 0.6 to 1.9) for lesions exhibiting proliferation without atypia and OR = 1.5 (95% CI, 0.4 to 5.6) for the diagnosis of atypical ductal hyperplasia. For women having both HER-2/neu amplification and a proliferative histopathologic diagnosis (either typical or atypical), the risk of breast cancer was more than seven-fold (OR = 7.2; 95% CI, 0.9 to 60.8). Overexpression of the HER-2/neu protein product, defined as membrane staining in 10% or more of epithelial cells, was found in 30% of the breast tumors but was not detected in any of the benign breast tissues. Case patients who had HER-2/neu gene amplification in their malignant tumor were more likely to have had HER-2/neu amplification in their prior benign biopsy (P =.06, Fisher's exact test). CONCLUSION: Women with benign breast biopsies demonstrating both HER-2/neu amplification and a proliferative histopathologic diagnosis may be at substantially increased risk for subsequent breast cancer.

Expression of a novel surface antigen MKW in childhood acute leukemia has prognostic significance.

A monoclonal antibody (MoAB) has been developed which reacts with a previously unidentified hematopoietic cell surface protein called MKW. This MoAB (anti-MKW) does not cluster with antibodies in any of the known cluster groups of differentiation. Blast cell expression of MKW was studied in 196 consecutively diagnosed children with acute lymphoblastic leukemia (ALL), 69 children with previously untreated acute myeloblastic leukemia (AML) and four children with secondary AML. MKW expression, clinical, laboratory and cytogenetic features at diagnosis, and treatment response and duration were examined for significant correlations. MKW was expressed on blasts from 12.8% of children with ALL and 24.6% of children with de novo AML. The expression of MKW appears to be more common in patients with secondary AML (three of four) than de novo AML (17 of 69). In patients with AML, the expression of MKW was correlated with an elevated initial leukocyte count (p = 0.0005) and poorer disease-free survival (p = 0.04). In patients with ALL, the expression of MKW was associated with a lower hemoglobin level (p less than 0.05) and a lower complete remission rate (p = 0.02). At a median follow-up of 4.6 years ALL patients with greater than or equal to 50% MKW+ blasts had a poorer event-free survival (EFS) than both MKW+ patients with 25-49% positive blasts (p = 0.03) and MKW+ patients (p = 0.0001). The disease-free survival was also poorer for ALL patients with greater than or equal to 50% MKW+ blasts (p = 0.02). In Cox regression analysis, the expression of MKW had an independent prognostic significance in children with ALL. As MKW is a unique cell surface antigen and its expression has prognostic significance in acute leukemias in children, further study in a larger series of patients is warranted.

Childhood acute promyelocytic leukemia: a rare variant of nonlymphoid leukemia with distinctive clinical and biologic features.

Of 251 consecutive cases of childhood acute nonlymphocytic leukemia (ANLL) seen at St. Jude Children's Research Hospital over a 12-year period, 16 (6.4%) were classified as promyelocytic according to the French-American-British definition. Patients with this form of leukemia were older at diagnosis than the group representing all other ANLL subtypes (median age, 14.8 vs. 9.0 years); they had lower leukocyte counts (median, 4.5 vs. 25.9 x 10(9)/liter), and a higher percentage were girls (68% vs. 44%). They also were much more likely to have a coagulation abnormality (75% vs. 13%). Only 44% of the promyelocytic group achieved complete remission, compared with 79% of the remaining patients (p = 0.001); however, after a median follow-up of 3.5 years, all but two of the responding patients with promyelocytic leukemia remain in complete remission. The majority of induction failures in the promyelocytic group (six of nine) resulted from complications that developed during periods of marrow hypoplasia or before hypoplasia was induced; whereas in the comparison group, more than half of the patients who failed had evidence of absolute or relative drug resistance. It is concluded that acute promyelocytic leukemia in children differs sufficiently from other subtypes of childhood ANLL to justify clinical trials of selective therapy. Recommendations for the use of heparin and blood component support in these patients are given.

Serum CD4, CD8, and interleukin-2 receptor levels in childhood acute myeloid leukemia.

Leukemic cell expression and serum levels of CD4, CD8, and interleukin-2 receptor (IL-2R) were determined at diagnosis for children or adolescents with acute myeloid leukemia (AML). Cellular expression of CD4 was detected in 18 of 62 cases, CD8 in none of 60 cases, and IL-2R in one of 33 cases tested. Myeloblasts of the M4 and M5 subtypes expressed CD4 significantly more frequently than other FAB subtypes (p = 0.0001). Serum levels of the three soluble factors (tested for 91 patients) were positively correlated with each other. Increased serum CD4 levels were significantly associated with cellular CD4 expression, high leukocyte count, M5 leukemia, spleen enlargement, and age less than 1 year. High serum CD8 levels correlated significantly with splenomegaly, extramedullary disease, absence of Auer rods, and high leukocyte count. Cases with high serum IL-2R levels were less likely to have Auer rods and more likely to have splenomegaly and M5 leukemia; serum levels greater than 750 U/ml were associated with a higher probability of treatment failure (p = 0.05), even after adjustment for other potential prognostic factors. Further studies of serum CD4, CD8, and IL-2R levels may help to clarify the immunoregulatory role of T-cells in patients with AML.

Current strategies for treatment of acute myeloid leukemia at St Jude Children's Research Hospital.

We examined the feasibility of maintaining specific plasma concentrations of ara-C and VP-16 in children with AML. Sixty-one children were treated with 6 sequential cycles of intensive chemotherapy consisting of: (1) cytarabine (ara-C)/VP-16, (2) ara-C/daunorubicin (Dauno), (3) VP-16/amsacrine (m-AMSA), (4) VP-16/5-azacytidine (5-Az), (5) ara-C/Dauno, and (6) ara-C/VP-16. Fifty-nine children had de novo AML, and 2 had a previous myelodysplastic syndrome. The number of patients with each specific FAB subtype was: M0-1; M1-7; M2-24; M3-7; M4-5; M5-11; and M7-6. Simultaneous continuous infusions of ara-C and VP-16 (cycle 1) given at individualized doses to achieve drug plasma concentrations of 1 microM and 30 microM, respectively, produced complete remission (CR) in 26 of 61 patients (43%); an additional 17 patients entered CR after Dauno/ara-C (cycle 2), and one patient required 4 cycles of chemotherapy to achieve CR (total CR rate = 72%). The preliminary 2-year event-free survival (EFS) for patients with FAB-M1 and -M2 AML was only 15% versus 40% for those with FAB-M4 and -M5 AML. Overall, 21 of the 61 patients remain in CR (2-yr EFS = 29%). We conclude that intense treatment with ara-C and VP-16 at doses individualized to achieve target plasma concentrations is feasible although severely myelosuppressive. It results in an acceptable CR rate, but does not improve EFS.(ABSTRACT TRUNCATED AT 250 WORDS)

Phase II clinical trial of pasireotide long-acting repeatable in patients with metastatic neuroendocrine tumors.

Pasireotide long-acting repeatable (LAR) is a novel somatostatin analog (SSA) with avid binding affinity to somatostatin receptor subtypes 1, 2, 3 (SSTR1,2,3) and 5 (SSTR5). Results from preclinical studies indicate that pasireotide can inhibit neuroendocrine tumor (NET) growth more robustly than octreotide in vitro. This open-label, phase II study assessed the clinical activity of pasireotide in treatment-naïve patients with metastatic grade 1 or 2 NETs. Patients with metastatic pancreatic and extra-pancreatic NETs were treated with pasireotide LAR (60 mg every 4 weeks). Previous systemic therapy, including octreotide and lanreotide, was not permitted. Tumor assessments were performed every 3 months using Response Evaluation Criteria in Solid Tumors (RECIST) criteria. The primary endpoint was progression-free survival (PFS). The secondary endpoints included overall survival (OS), overall radiographic response rate (ORR), and safety. Twenty-nine patients were treated with pasireotide LAR (60 mg every 4 weeks) and 28 were evaluable for response. The median PFS was 11 months. The most favorable effect was observed in patients with low hepatic tumor burden, normal baseline chromogranin A, and high tumoral SSTR5 expression. Median OS has not been reached; the 30-month OS rate was 70%. The best radiographic response was partial response in one patient (4%), stable disease in 17 patients (60%), and progressive disease in ten patients (36%). Although grade 3/4 toxicities were rare, pasireotide LAR treatment was associated with a 79% rate of hyperglycemia including 14% grade 3 hyperglycemia. Although pasireotide appears to be an effective antiproliferative agent in the treatment of advanced NETs, the high incidence of hyperglycemia raises concerns regarding its suitability as a first-line systemic agent in unselected patients. SSTR5 expression is a potentially predictive biomarker for response.

Differential vascular response to laser photothermolysis.

Individual blood vessels in the chick choriallantoic membrane were selectively coagulated through photothermolysis, using pulsed laser irradiation at 585 nm. Pulse durations were chosen to be 0.45 ms and 10 ms, which correspond to the thermal relaxation times in blood vessels of 30 microns and 150 microns diameter, respectively. The short pulses, at a light fluence F = 3 Jcm-2, caused permanent occlusion of vessels of 40 microns diameter or less, whereas larger caliber vessels (60-120 microns) required F = 4-5 Jcm-2. The long-duration pulses, at F = 7 Jcm-2, caused coagulation of the larger diameter vessels; the small-caliber vessels and capillaries showed resistance to photothermolysis and required multiple exposures to achieve coagulation. The fluence versus diameter (F versus d) relationship for coagulation was calculated for the two pulse durations. The energy deposited in a cylindrical absorber of diameter d by an optical field, incident perpendicular to the vessel, was expressed analytically and compared with the energy required to coagulate a blood vessel of the same lumen dimeter. When thermal diffusion is incorporated into the model, our findings can be accounted for quantitatively. This information will be of use for improving the laser treatment of port wine stains and other vasculopathies. A surprising observation was that arterioles were damaged at lower incident energy densities than venules having the same lumen diameter, despite the fact that absorbance in oxygen-rich and oxygen-poor blood is the same at 585 nm.

Lower prevalence of the debrisoquin oxidative poor metabolizer phenotype in American black versus white subjects.

Our objective was to determine whether there are differences in debrisoquin hydroxylase (P450IID6) activity between American black subjects and white subjects. Phenotype was assigned in a group of 586 unrelated white and black children with use of dextromethorphan as the substrate probe. Restriction fragment length polymorphism analysis of genomic deoxyribonucleic acid (DNA) was performed in a subset of subjects by use of a full length complementary DNA for P450IID6. Thirty-seven of 480 (7.7%) white children were poor metabolizers compared with 2 of 106 (1.9%) black children (p = 0.03). Among 41 white subjects and 18 black subjects, there were significant differences (p less than 0.05) in two XbaI DNA restriction fragments; the 44 kb fragment was more common and the 29 kb fragment was less common in black versus white extensive metabolizers. There is a lower prevalence of the debrisoquin poor metabolizer phenotype among American black persons, which could have implications for efficacy or toxicity of drugs metabolized by this enzyme, as well as for racial differences in the prevalence of diseases associated with the debrisoquin oxidative phenotype.

On the relationship of matrix association and DNA replication.

The nuclear matrix is believed to contain sites of assembly of protein complexes that catalyze the initiation of DNA replication as well as DNA elongation. To explore this relationship, DNA replicated by human fibroblasts at the beginning of the S phase was purified and used to construct a cosmid library. Hybridization studies with a subgroup of clones (about one-sixth of the total clones in this library) showed that many of them were highlighted by probes prepared from early replicating DNA, as well as from nuclear matrix-associated DNA. Statistical analysis showed a positive correlation between these hybridization results. We seek to identify origins of replication that are activated early in the S phase of the cell cycle in human cells. Therefore, clones isolated from this library are being analyzed for the presence of structural motifs that have been found in other origins of replication and for potential sites of attachment to the nuclear matrix. This method of analysis is illustrated here using the published sequences for the origins of replication reported for the human lamin B2 and HPRT genes.