Phase I trial of intravenous fenretinide (4-HPR) plus safingol in advanced malignancies

PURPOSE

Fenretinide (4-HPR) is a synthetic retinoid that induces cytotoxicity through dihydroceramide production. Safingol, a stereochemical-variant dihydroceramide precursor, exhibits synergistic effects when administered with fenretinide in preclinical studies. We conducted a phase 1 dose-escalation clinical trial of this combination.

METHODS

Fenretinide was administered as a 600 mg/m2 24-h infusion on Day 1 of a 21-day cycle followed by 900 mg/m2/day on Days 2 and 3. Safingol was concurrently administered as a 48-h infusion on Day 1 and 2 using 3 + 3 dose escalation. Primary endpoints were safety and maximum tolerated dose (MTD). Secondary endpoints included pharmacokinetics and efficacy.

RESULTS

A total of 16 patients were enrolled (mean age 63 years, 50% female, median three prior lines of therapy), including 15 patients with refractory solid tumors and one with non-Hodgkin lymphoma. The median number of treatment cycles received was 2 (range 2-6). The most common adverse event (AE) was hypertriglyceridemia (88%; 38% ≥ Grade 3), attributed to the fenretinide intralipid infusion vehicle. Other treatment-related AEs occurring in ≥ 20% of patients included anemia, hypocalcemia, hypoalbuminemia, and hyponatremia. At safingol dose 420 mg/m2, one patient had a dose-limiting toxicity of grade 3 troponinemia and grade 4 myocarditis. Due to limited safingol supply, enrollment was halted at this dose level. Fenretinide and safingol pharmacokinetic profiles resembled those observed in monotherapy trials. Best radiographic response was stable disease (n = 2).

CONCLUSION

Combination fenretinide plus safingol commonly causes hypertriglyceridemia and may be associated with cardiac events at higher safingol levels. Minimal activity in refractory solid tumors was observed.

TRIAL REGISTRATION NUMBER

NCT01553071 (3.13.2012).

Pomalidomide, dexamethasone, and daratumumab immediately after lenalidomide-based treatment in patients with multiple myeloma: updated efficacy, safety, and health-related quality of life results from the phase 2 MM-014 trial

Patients with relapsed/refractory multiple myeloma (RRMM) need proven subsequent therapies after early-line lenalidomide treatment failure. The phase 2 MM-014 trial (NCT01946477) investigated pomalidomide, dexamethasone, and daratumumab after 1 to 2 prior treatment lines (62.5%, 1 prior line) in patients with RRMM and prior lenalidomide (75.0%, lenalidomide refractory). With a median follow-up of 28.4 months, overall response rate was 77.7% (52.7% achieved very good partial response or better) and median progression-free survival was 30.8 months. For patients with lenalidomide-refractory disease, these outcomes were 76.2%, 47.6%, and 23.7 months, respectively. No new safety signals were observed; 64.3% experienced grade 3/4 neutropenia. Health-related quality of life was preserved or trended toward improvement through 12 treatment cycles. Pomalidomide, dexamethasone, and daratumumab given immediately after early-line lenalidomide-based treatment continues to demonstrate safety and efficacy, supporting pomalidomide-dexamethasone as a foundation of combination therapy in RRMM and providing evidence that the immunomodulatory agent class delivers benefit after lenalidomide treatment failure.

Pomalidomide, dexamethasone, and daratumumab in relapsed refractory multiple myeloma after lenalidomide treatment

Patients with multiple myeloma who have relapsed after or become refractory to lenalidomide in early treatment lines represent a clinically important population in need of effective therapies. The safety and efficacy of pomalidomide, low-dose dexamethasone, and daratumumab was evaluated in lenalidomide-pretreated patients with relapsed or refractory multiple myeloma (RRMM) after one to two prior treatment lines in the phase 2 MM-014 study. Patients received pomalidomide 4 mg daily from days 1-21 and dexamethasone 40 mg weekly (28-day cycles). Daratumumab 16 mg/kg was administered per label. Primary endpoint was overall response rate (ORR); secondary endpoints included progression-free survival (PFS) and safety. Per protocol, all patients (N = 112) had received lenalidomide in their most recent prior regimen (75.0% lenalidomide refractory). ORR was 77.7% (76.2% in lenalidomide-refractory patients); median follow-up was 17.2 months. Median PFS was not reached (1-year PFS rate 75.1%). The most common hematologic grade 3/4 treatment-emergent adverse event was neutropenia (62.5%). Grade 3/4 infections were reported in 31.3% of patients, including 13.4% with grade 3/4 pneumonia. These results demonstrate the safety and efficacy of pomalidomide-based therapy as early as second line in patients with RRMM, even immediately after lenalidomide failure, indicating that switching from the immunomodulatory agent class is not necessary.

Pixantrone plus rituximab versus gemcitabine plus rituximab in patients with relapsed aggressive B-cell non-Hodgkin lymphoma not eligible for stem cell transplantation: a phase 3, randomized, multicentre trial (PIX306)

PIX306 was a phase 3, randomised, single-blind, multicentre trial conducted in adult patients with diffuse large B-cell lymphoma (DLBCL) or follicular lymphoma (FL) grade 3 who relapsed after ≥1 rituximab-containing regimen and were not eligible for a stem cell transplant. Patients were randomised 1:1 to pixantrone 50 mg/m² or gemcitabine 1000 mg/m² on days 1, 8 and 15 of a 28-day cycle, combined with rituximab 375 mg/m² on day 1, for up to six cycles. Patients were followed for up to 96 weeks. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), complete response (CR) rate, overall response rate (ORR) and safety. Overall, 312 patients were randomised (median age 73·0 years). The study did not meet its primary endpoint. Median PFS [95% confidence interval (CI)] was 7·3 months (5·2-8·4) with pixantrone + rituximab (PIX + R) and 6·3 months (4·4-8·1) with gemcitabine + rituximab [GEM + R; hazard ratio (HR): 0·85; 95% CI 0·64-1·14; P = 0·28]. Median OS was 13·3 (10·1-19·8) months with PIX + R and 19·6 (12·4-31·9) months with GEM + R (HR: 1·13; 95% CI 0·83-1·53). ORR was 61·9% and 43·9% respectively and CR rate 35·5% and 21·7%. The incidence of adverse events, including cardiac events, was not statistically significant different between PIX + R and GEM + R.

A health-related quality-of-life (HRQoL) analysis of pomalidomide + low-dose dexamethasone + daratumumab in relapsed refractory multiple myeloma (RRMM) after lenalidomide treatment

8025

Background: Treatment (Tx) of RRMM is complex and requires evaluation of disease and patient (pt) factors to maximize efficacy and minimize toxicity. HRQoL has become an important aspect of MM Tx, as survival has improved with therapeutic advances. Results of the ongoing phase 2 MM-014 trial (NCT01946477) have demonstrated that pomalidomide (POM) + low-dose dexamethasone (LoDEX) + daratumumab (DARA) is safe and effective in RRMM pts after first- or second-line lenalidomide (LEN)-based Tx failure. Here we report the impact of this regimen on HRQoL. Methods: RRMM pts with 1 to 2 prior Tx lines, LEN-based Tx as their most recent regimen, and progressive disease during or after their last Tx line received POM + LoDEX + DARA in 28-day cycles (MM-014 cohort B). HRQoL, an exploratory endpoint for cohort B, was assessed via EuroQol’s EQ-5D. Results: As of October 15, 2018, 108 pts were evaluable for HRQoL. Baseline characteristics were similar to those of the ITT population (N = 112). EQ-5D completion rates for each cycle (1-6) were ≥ 88%. Mean change from baseline in the EQ-5D index and VAS health score was stable through 6 Tx cycles. At cycle 6, 28.8% and 39.0% of pts achieved minimum clinically important improvement in the EQ-5D index (≥ 0.1) and VAS health score (≥ 6), respectively. EQ-5D index values were stable, with a trend toward improvement in usual activities, pain/discomfort, and anxiety/depression (Table). Conclusions: In RRMM pts with early-line LEN Tx failure, HRQoL was maintained or trended toward improvement with POM + LoDEX + DARA, despite the combination of 3 drugs with distinct toxicities. These findings further support the earlier use of POM-based Tx in RRMM immediately after LEN failure. Clinical trial information: NCT01946477. [Table: see text]

Risk of secondary hematologic malignancies and tolerability in patients with ovarian cancer treated with PARP inhibitors: A systematic review and meta-analysis of four phase III randomized controlled trials

e23056

Background: Poly adenosine diphosphate ribose polymerase (PARP) inhibitors have shown to improve survival in ovarian cancer (OC) through synthetic lethality with potentiation of double-strand breaks in tumor cells. Yet, there are concerns of secondary hematologic malignancies (SHM) and notable adverse events (AE) leading to treatment discontinuation (TD), interruption (TI), or dose reduction (DR). Methods: MEDLINE, EMBASE databases and meeting abstracts from inception through January 2019 were queried. Phase 3 RCTs utilizing PARP inhibitors maintenance in OC were eligible. Mantel-Haenszel (MH) method was used to calculate the estimated pooled risk ratio (RR) with 95% confidence interval (CI). Random effects model was applied. Results: A total of 1792 patients from four phase III RCTs were included. The study arm used olaparib or niraparib or rucaparib while the control arm utilized placebo. Almost all patients in the SOLO-2 & -1 trials had a gBRCA mutation, while there were patients with and without the said mutation in the other two studies. The SHM incidence was 1.25% in PARP inhibitors group vs 0.83% in control group (RR, 1.15; 95% CI: 0.41–3.22, p = 0.79). TI due to AE was 59.71% in study group versus 11.39% in control arm (RR, 4.94; 95% CI: 2.44 – 9.96, P < 0.001). DR was reported in 47.73% in PARP inhibitors arm versus 6.86% in control group (RR, 7.73; 95% CI: 4.17 – 14.31, P < 0.001). TD rate was 10.97% higher in study group compared to control arm (RR, 6.63; 95% CI: 3.55 – 11.31, P < 0.001). Conclusions: The risk of SHM was not significantly increased in PARP inhibitors group. However, patients on PAPR inhibitors arm experienced significant drop outs due to AE, despite showing significant improvement in PFS in studies. Proper supportive care may enhance compliance.

Pixantrone-rituximab versus gemcitabine-rituximab in relapsed/refractory aggressive non-Hodgkin lymphoma

We describe the rationale and design of the ongoing randomized, active-controlled, multicenter, Phase III study evaluating the efficacy of pixantrone and rituximab versus gemcitabine and rituximab in patients with diffuse large B-cell lymphoma or follicular grade 3 lymphoma, who are ineligible for high-dose chemotherapy and stem cell transplantation, and who failed front-line regimens containing rituximab. The administration schedule is pixantrone 50 mg/m(2) intravenously (iv.) or gemcitabine 1000 mg/m(2) iv. on days 1, 8 and 15, combined with rituximab 375 mg/m(2) iv. on day 1, up to six cycles. Pixantrone has a conditional European marketing approval for monotherapy in adults with multiple relapsed or refractory aggressive B-cell non-Hodgkin lymphoma. Our trial explores the efficacy of combining pixantrone with rituximab and completes postauthorization measures.

TRIAL REGISTRATION NUMBER

NCT01321541.

Results of a phase II study of bendamustine and ofatumumab in untreated indolent B cell non-Hodgkin's lymphoma

The efficacy/tolerability of bendamustine, a unique alkylator, plus ofatumumab, a human anti-CD20 monoclonal antibody, was evaluated for previously untreated indolent B cell non-Hodgkin's lymphoma (NHL). The study investigated whether the overall response rate (ORR) for bendamustine-ofatumumab was similar to historical bendamustine-rituximab ORRs (≥90 %). In this multicenter, open-label, single-arm, phase II study, patients received six planned 28-day cycles of bendamustine (90 mg/m(2) on days 1 and 2 of each cycle) and ofatumumab (300 mg on day 1, 1000 mg on day 8 of cycle 1, and on day 1 of subsequent cycles). The primary outcome was ORR. Secondary objectives included safety and tolerability. Exploratory evaluations included percentage of patients with positive baseline [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) scans who converted to negative postbaseline and quality of life (QOL) scores. The treated/safety analysis population received ≥1 dose of either therapy. The bendamustine-ofatumumab ORR was 90 % (95 % confidence interval, 77.8-96.6) in 49 treated patients (67 % complete response, 22 % partial response). No patients had progressive disease. Bendamustine-ofatumumab was acceptably tolerated. All 49 patients had ≥1 adverse event, the most common being nausea (61 %), fatigue (55 %), and infusion-related reactions (45 %, all but 1 occurring during cycle 1). The proportion of patients whose FDG-PET scans converted to negative postbaseline was 88 %. Changes in QOL scores were minor. In patients with treatment-naive, indolent B cell NHL, bendamustine-ofatumumab exhibited a high degree of activity (90 % ORR), comparable with historical bendamustine-rituximab ORRs (≥90 %), and was adequately tolerated ( ClinicalTrials.gov identifier: NCT01108341).

A self-regulating cell culture analog device to mimic animal and human toxicological responses

The overall goal of this project is the development of a new methodology for translating advances in molecular level understanding of toxicological responses into a predictive tool for dose response in whole animals and humans exposed to single compounds or mixtures of compounds. The methodology incorporates a mechanistic cellular level model into a PBPK (physiologically based pharmacokinetic) model which simultaneously guides the development of an in vitro cell culture analog (CCA) to the PBPK. Where the PBPK specifies an organ, (e.g., liver) the in vitro or CCA system contains a compartment with the appropriate cell or cell population (e.g., hepatocytes for the liver). The CCA has significant advantages over other in vitro systems and PBPK systems used independently for evaluating metabolic responses to drugs or potentially toxic chemicals where the exchange of metabolites between organs is likely to be important. The CCA system is superior to a PBPK because an a priori description of complete metabolism is not required and secondary, unexpected interactions can be detected. The CCA system, unlike other in vitro systems, gives a dynamic response that realistically simulates in vivo interactions between organs. Furthermore, the CCA allows dosing on the same basis as animal tests (e.g., milligrams per kilogram of body mass equivalent). Because the construction of a CCA is guided by a PBPK, this approach allows extrapolation to low doses and across species, including extrapolation to humans. We have constructed a prototype system and have conducted proof-of-concept experiments using naphthalene as a test chemical. These experiments clearly demonstrate the ability to generate a reactive metabolite in one compartment and detect its effects (on LDH release and glutathione depletion) in a second compartment. However, this prototype device would be expensive to replicate and requires nearly constant supervision from a trained investigator. For this concept to replace animals an inexpensive, self-regulating device is needed. An initial design to accomplish this goal is described as well as the corresponding model using naphthalene as a test compound. (c) 1996 John Wiley & Sons, Inc.

Phase I trial of fenretinide (4-HPR) intravenous emulsion in hematologic malignancies: A California Cancer Consortium study (PhI-42)

8073

Background: Fenretinide (4-HPR) is a cytotoxic retinoid with broad anticancer activity in preclinical studies. Due to limited bioavailability of a capsule formulation an intravenous intralipid-like emulsion formulation (4-HPR ILE) was developed to increase systemic exposures. Methods: 4-HPR was administered as a continuous intravenous infusion for 120 hrs every 21 days. Systemic toxicities, responses, and pharmacokinetics were assessed. Accelerated Simon design proceeded until moderate or dose-limiting toxicities (DLT) were scored on Course 1. Doses were 80 mg/m2/day to 1810 mg/m2/day. Patients with asymptomatic hypertriglyceridemia were scored separately. All patients were heavily pretreated. Results: Toxicity-evaluable patients = 25. At 1810 mg/m2/day, two patients experienced DLT hypertriglyceridemia, one with transient Grade 2 pancreatitis; at 1280 mg/m2/day (8 pts), two had asymptomatic Grade 4 hypertriglyceridemia, one experienced DLT pleural effusions; at 905 mg/m2/day (6 pts) 2 experienced asymptomatic Grade 4 hypertriglyceridemia; All 5 pts at 640 mg/m2/day tolerated treatment. Pharmacokinetics showed a dose-to-plasma level relationship with mean steady-state 4-HPR levels of ~mid-20’s μM (640 mg/m2); ~mid-30’s μM (905 mg/m2/day); and ~mid-50’s μM (1280 mg/m2). Responses to date include a 64% CR+PR+SD response rate (36% CR+PR response rate) in 11 relapsed T-cell lymphomas which included histone deacetylase inhibitor-refractory patients, and a PRu response in a NHL B-cell lymphoma. Reversible hypertriglyceridemia related to the intralipid vehicle accounted for 6/7 DLTs. Conclusions: MTD = 1280 mg/m2/day x 5 days, every three weeks. 4-HPR ILE was safely administered and obtained 4-HPR plasma levels 6 -7 times higher than previously obtained using oral capsules. Durable complete responses were observed in T-cell lymphomas from 905 – 1810 mg/m2/day. An expanded cohort is accruing to a dosing schedule modified to decrease asymptomatic hypertriglyceridemia of 600 mg/m2 on Day 1 (to allow for induction of serum lipases) followed by 1200 mg/m2 Days 2-5. Supported by NCI U01 CA062505 and CPRIT RP10072.

Final results of a phase I study using oral temozolomide (TMZ) daily for 14 days with weekly paclitaxel in patients (pts) with advanced malignancies

12020

Background: TMZ is an alkylating agent with activity in a variety of neoplasms. The optimal schedule of administration for TMZ has not been established and only a few studies have studied it in combination with other agents. Repair of TMZ-induced DNA damage is associated with the activity of O-6 alkylguanine-DNA-alkyl transferase (AGT). Preclinical and clinical data indicate that prolonged exposure to TMZ results, not only in enhanced DNA alkylation, but also in depletion of AGT. This serves as the rationale to study TMZ using protracted schedules. Methods: The aim of this study was to determine the maximum tolerated dose (MTD) and dose limiting toxicity (DLT) of oral TMZ given daily for 14 days with weekly paclitaxel in pts with advanced cancers. Forty-five pts received 136 cycles of TMZ at escalating doses (50, 75, 100, 125 and 150 mg/m2/day × 14 days) plus paclitaxel at 80 mg/m2 on days 1, 8, and 15. Pts were stratified as lightly (LP) or heavily (HP) pretreated and MTD defined as the dose level (DL) at which 1/6 patients developed DLT. Results: Twenty-four LP patients were treated at 5 DLs with all but one evaluable for toxicity. Febrile neutropenia and grade 3 thrombocytopenia were the DLTs. MTD in this group was the 125 mg/m2/day level. Twenty-six HP were treated at 5 DLs and 21 were evaluable for toxicity. Febrile neutropenia and grade 3 thrombocytopenia were the DLTs. MTD for this group was also 125 mg/m2/day. Thirty-eight (84%) pts were evaluable for response after 2 cycles of therapy. Three (8%) pts had a partial response (lung, lymphoma, ependymoma), 20 (53%) remained stable and 15 (39%) developed disease progression. Six (16%) pts remained stable for 6 cycles or more (2 sarcomas, 2 lung, 1 pancreas, 1 glioblastoma). Conclusions: We concluded that combining oral TMZ at a dose of 125 mg/m2/day for 14 days with standard-dose weekly paclitaxel is safe in both HP and LP pts.

[Table: see text]

Acute mitral valve regurgitation created in sheep using echocardiographic guidance

BACKGROUND AND AIM OF STUDY

This study was designed to determine: (i) Whether acute mitral valve regurgitation (MVR) due to chordal rupture can be reproducibly created under echocardiographic guidance; (ii) what degree of MVR can be created; (iii) what degree of acute regurgitation is survivable; and (iv) whether acute MVR due to chordal rupture progresses over time.

METHODS

In a pilot group of six juvenile farm-bred sheep, selected chordae tendineae were ruptured using either a biopsy needle or endoscopic scissors under echocardiographic guidance, without need for cardiopulmonary bypass. Sheep were sacrificed acutely (n = 2), and at six weeks (n = 2) or eight weeks (n = 2). When the technique was optimized, five sheep entered a study group in which chords were ruptured using endoscopic scissors; the sheep were sacrificed 16 weeks after surgery.

RESULTS

In the pilot study, acute MVR (grade 2-4+) was produced in all sheep, normal ventricular wall motion was maintained, with minimal progression of regurgitation over time. In one pilot sheep which did not survive, grade 4+ MVR was created acutely. Use of endoscopic scissors was preferable to the biopsy needle. In the study group, acute MVR (grade 2-4+) was produced in all five sheep, and was still present at 16 weeks, with progression in only one animal.

CONCLUSIONS

This pilot study demonstrated that controlled degrees of survivable acute MVR due to chordal rupture can be created under echocardiographic guidance, with minimal progression of MVR over time. This animal model can be applied to investigate the pathogenesis of clinical MVR, and to suggest appropriate medical or surgical intervention.

In-vivo measurement of intrauterine gases and acid-base values early in human pregnancy

A new multiparameter sensor that combines electrochemical and fibre-optic technology was used for continuous in-vivo investigation of pH, carbon dioxide partial pressure (PCO(2)), oxygen partial pressure (PO(2)), bicarbonate concentration (HCO(3)(-)), base excess, and oxygen saturation (O(2)Sat) early in human pregnancy. The sensor was inserted into the amniotic cavity and the placental bed of 16 pregnancies at 10-15 weeks gestation, before termination under general anaesthesia. Amniotic fluid and retroplacental blood from the same site were also aspirated and analysed by means of cartridges and a portable blood gas analyser. Eleven series of measurements were obtained. The variation in measurements over the 5 min of monitoring was </=10% for all parameters. The sensor was damaged during insertion into the amniotic cavity in one case and in the placental bed in four cases. Measurements of PO(2) in both the amniotic cavity and the placental bed and of pH in the placental bed were higher using the cartridges than in vivo. The results indicated that in-vivo monitoring of fetoplacental gas and acid-base with a sensor is stable and accurate. Such technology will be helpful in improving our understanding of the fetoplacental metabolism in normal and complicated pregnancies.

Light-chain paraproteins with lupus anticoagulant activity

A patient with newly diagnosed multiple myeloma manifested by urine kappa light-chain excretion and a small monoclonal spike (0.4 g/dl), presented with lower extremity deep venous thrombosis. A preheparin plasma-activated partial thromboplastin time (aPTT) was prolonged at 68 sec (normal control 26-42 sec). Additional studies confirmed the presence of lupus anticoagulant activity in the serum: the modified Russell Viper Venom Time (MRVVT) was 73 sec (normal control 24-42 sec) and with a 50:50 mix of the patient's plasma and pooled normal plasma, the MRVVT remained prolonged. Kappa light chains (LC) were isolated from the patient's urine and their purity confirmed by electrophoresis and immunofixation using specific immunoglobulin antisera. The patient's LC mixed with pooled normal plasma demonstrated LA activity by in vitro clotting tests (plasma-activated partial thromboplastin time 62 sec, with normal control of 45 sec), MRVVT of 44 sec with normal control of 35 sec. Purified urinary kappa light chains from a control patient with multiple myeloma and normal clotting studies, failed to prolong either the plasma-activated partial thromboplastin time or the MRVVT. We hypothesize that kappa LC in our patient demonstrated LA activity, which was unique to these LCs. Paraproteins with LA activity, to date, have included only intact immunoglobulins (Ig). While intact Ig paraproteins have been reported to possess LA activity, this is the first report to our knowledge of light-chain paraproteins possessing similar activity and resulting in clinically evident thrombosis. Light chain paraproteins could serve as useful models for further study of the mechanisms of activity of acquired LA inhibitors.

Placental transfer of fentanyl in early human pregnancy and its detection in fetal brain

We have investigated the transfer of fentanyl across the early human placenta in 38 women (8-14 weeks' gestation) undergoing termination of pregnancy. After administration of a bolus dose of fentanyl 2 micrograms kg-1 at induction of anaesthesia, maternal blood n = 38), placenta (n = 38), amniotic fluid (n = 38) and fetal brain (n = 7) samples were collected and assayed for fentanyl by radioimmunoassay. Fentanyl was detected in all placental and fetal brain samples but not in amniotic fluid. There was a rapid decrease in fentanyl concentrations in maternal serum after the bolus but placental concentrations had not started to decline 30 min later. There was no difference in placental drug concentrations at different gestational ages. These data suggest that there is rapid transfer of fentanyl to the fetus in early pregnancy and that the drug remains in fetal tissue for some time after the initial dose is given to the mother.

Cloning and sequence analysis of the human acidic fibroblast growth factor gene and its preservation in leukemia patients

Acidic fibroblast growth factor (aFGF), also known as heparin-binding growth factor 1, is a mitogen for a variety of mesoderm- and neuroectoderm-derived cells. Several different aFGF mRNA species resulting from alternative splicing have been reported. These results suggest that the gene structure and regulatory mechanism for gene expression of aFGF are complex. As a first step toward understanding aFGF gene structure, we have isolated nine overlapping genomic DNA clones spanning 54 kbp and determined the complete DNA sequences of all three coding exons. Comparison of the nucleotide sequences between the human and bovine DNA showed that the sequence similarity extended 2400 bp downstream from the coding region. Cloning of the aFGF gene allowed us to characterize this locus in acute nonlymphocytic leukemia (ANLL) patients. A fraction of ANLL patients (10-20%) have a deletion in the long arm of chromosome 5, whose distal breakpoint overlaps the aFGF locus. Therefore, a prospective cohort of eight ANLL patients was screened using three different repetitive sequence-free probes derived from the aFGF locus. Using beta-globin gene as a normalization probe for hybridizing band intensities, we conclude that there is no allelic loss or gross rearrangement within the 40 kbp stretch of the aFGF gene locus in ANLL patients with or without 5q- deletion. Consistent with this observation, the aFGF mRNA was not detected in the mononuclear cells derived from either an ANLL patient or a normal individual as judged by the reverse transcription and polymerase chain reaction. We also identified a DNA fragment, 10.7 kbp upstream from the first coding exon of human aFGF, whose sequence is conserved in both the primate and rodent genomes. Further characterization of this fragment is likely to provide insight into the significance of this high degree of conservation.

LEUKOPLAKIA AND ALLIED MOUTH CONDITIONS

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