Updated analysis of progression-free survival with first subsequent therapy (PFS2) and safety in the SPARTAN study of apalutamide (APA) in patients (pts) with high-risk nonmetastatic castration-resistant prostate cancer (nmCRPC)

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Background: In the phase 3 SPARTAN study, compared with placebo (PBO), APA, a next-generation androgen receptor inhibitor, decreased the risk of distant metastasis or death by 72% (hazard ratio [HR], 0.28; p < 0.0001) in men with high-risk nmCRPC. After 1 year of additional follow-up, PFS2 and safety were reevaluated to ensure maintenance of benefit against potential harm. Methods: Pts with nmCRPC and prostate-specific antigen doubling time of ≤ 10 mos were randomized 2:1 to APA (240 mg QD) + androgen deprivation therapy (ADT) or PBO + ADT. All pts who developed distant metastasis, determined by blinded independent central review, were eligible to receive subsequent therapy including open-label treatment with abiraterone acetate + prednisone, provided by the sponsor. The exploratory PFS2 end point (time from randomization to disease progression on subsequent anticancer therapy or death) was evaluated, as was incidence of treatment-emergent adverse events (TEAEs). Results: Median treatment duration with APA was 25.7 mos; with PBO, 11.5 mos (original analysis, mos: APA, 19.2; PBO, 11.2). Pts randomized to APA continued to show significant benefit in PFS2 (HR, 0.5; 95% CI, 0.39-0.63; p < 0.0001) vs PBO (APA median time to PFS2 not reached vs PBO 39.3 mos). At a median follow-up of 32 mos, 51.3% of pts receiving APA, 8% of the 75 pts who crossed over from PBO to APA, and 99.7% of remaining PBO pts had discontinued study treatment. Rates of discontinuations due to progressive disease and AEs were 27.3% and 12.7%, respectively, in the APA group and 73.4% and 8.4% in the PBO group. There was no substantial change in the incidence of TEAEs in the APA group at the 1-year update. With regard to drug specific TEAEs, there were no grade 4 or 5 events; grade 3 TEAEs consisted of rash, 5.2%; falls, 2.4%; fractures, 3.1%; hypothyroidism, 0%; and seizures, 0%. Conclusions: APA was previously shown to result in an improvement in metastasis-free survival and symptomatic progression. With a median APA treatment duration of 25.7 mos, APA continues to show significant benefit in PFS2, and its safety profile remains unchanged. Clinical trial information: NCT01946204.

Apalutamide Treatment and Metastasis-free Survival in Prostate Cancer

BACKGROUND

Apalutamide, a competitive inhibitor of the androgen receptor, is under development for the treatment of prostate cancer. We evaluated the efficacy of apalutamide in men with nonmetastatic castration-resistant prostate cancer who were at high risk for the development of metastasis.

METHODS

We conducted a double-blind, placebo-controlled, phase 3 trial involving men with nonmetastatic castration-resistant prostate cancer and a prostate-specific antigen doubling time of 10 months or less. Patients were randomly assigned, in a 2:1 ratio, to receive apalutamide (240 mg per day) or placebo. All the patients continued to receive androgen-deprivation therapy. The primary end point was metastasis-free survival, which was defined as the time from randomization to the first detection of distant metastasis on imaging or death.

RESULTS

A total of 1207 men underwent randomization (806 to the apalutamide group and 401 to the placebo group). In the planned primary analysis, which was performed after 378 events had occurred, median metastasis-free survival was 40.5 months in the apalutamide group as compared with 16.2 months in the placebo group (hazard ratio for metastasis or death, 0.28; 95% confidence interval [CI], 0.23 to 0.35; P<0.001). Time to symptomatic progression was significantly longer with apalutamide than with placebo (hazard ratio, 0.45; 95% CI, 0.32 to 0.63; P<0.001). The rate of adverse events leading to discontinuation of the trial regimen was 10.6% in the apalutamide group and 7.0% in the placebo group. The following adverse events occurred at a higher rate with apalutamide than with placebo: rash (23.8% vs. 5.5%), hypothyroidism (8.1% vs. 2.0%), and fracture (11.7% vs. 6.5%).

CONCLUSIONS

Among men with nonmetastatic castration-resistant prostate cancer, metastasis-free survival and time to symptomatic progression were significantly longer with apalutamide than with placebo. (Funded by Janssen Research and Development; SPARTAN ClinicalTrials.gov number, NCT01946204 .).

SPARTAN, a phase 3 double-blind, randomized study of apalutamide (APA) versus placebo (PBO) in patients (pts) with nonmetastatic castration-resistant prostate cancer (nmCRPC)

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Background: Pts with nmCRPC are at risk for developing metastatic disease and cancer-specific mortality. There are no approved treatments for nmCRPC. APA is an orally administered next-generation androgen receptor inhibitor with antitumor activity in CRPC. SPARTAN evaluated the effects of APA on metastasis-free survival (MFS) in men with nmCRPC. Methods: Pts with nmCRPC and prostate-specific antigen doubling time (PSADT) of ≤ 10 mos were randomized 2:1 to APA (240 mg QD) or PBO. The primary end point was MFS, defined as the time from randomization to first radiographic distant metastasis (per blinded central review) or death. Secondary end points included time to metastasis (TTM), progression-free survival (PFS), time to symptomatic progression (SymProg), and overall survival (OS). Pts were eligible to receive study-provided abiraterone acetate plus prednisone after developing distant metastases. Second progression-free survival (PFS2, the time from randomization to disease progression or death after first treatment for metastatic CRPC) was also evaluated. Results: 1207 pts were randomized. Baseline PSADT was < 5 mos in both groups. APA decreased the risk of distant metastasis or death by 72% (HR = 0.28; 95% CI, 0.23-0.35; p < 0.0001), with a median MFS of 40.5 vs 16.2 mos in the PBO group. Secondary end points (TTM, PFS, and SymProg) were all significantly improved. At an interim analysis for OS, there was a trend favoring APA. At a median follow-up of 20.3 mos, 61% of APA and 30% of PBO pts were still on treatment. Rates of discontinuation due to adverse events were low in both groups (10.7% APA, 6.3% PBO). Mean baseline health-related quality of life scores were maintained with treatment, with no difference between groups over time. Of those whose disease progressed, 80% of PBO and 56% of APA pts received therapy for metastatic CRPC. PFS2 was significantly longer for APA vs PBO. Conclusions: APA significantly improved median MFS by 2 years in men with nmCRPC. APA also significantly increased TTM, PFS, SymProg, and PFS2. APA was associated with improved OS. These results support the addition of APA to androgen deprivation therapy in men with nmCRPC. Clinical trial information: NCT01946204.

Pegylated liposomal doxorubicin plus docetaxel significantly improves time to progression without additive cardiotoxicity compared with docetaxel monotherapy in patients with advanced breast cancer previously treated with neoadjuvant-adjuvant anthracycline therapy: results from a randomized phase III study

PURPOSE

To determine whether the combination of pegylated liposomal doxorubicin (PLD) and docetaxel significantly prolongs time to disease progression compared with docetaxel alone without an increase in cardiac toxicity in women with advanced breast cancer who had experienced relapse at least 1 year after prior adjuvant or neoadjuvant anthracycline therapy.

PATIENTS AND METHODS

This international, phase III study randomly assigned 751 patients to receive either docetaxel 75 mg/m(2) (n = 373) or PLD 30 mg/m(2) followed by docetaxel 60 mg/m(2) every 21 days (n = 378) and continued until disease progression or prohibitive toxicity. The primary end point was time to progression (TTP). Secondary end points were overall survival (OS), objective response rate (ORR), cardiac toxicity, and safety.

RESULTS

Treatment with PLD-docetaxel significantly improved median TTP from 7.0 to 9.8 months (hazard ratio [HR] = 0.65; 95% CI, 0.55 to 0.77; P = .000001) and the ORR from 26% to 35% (P = .0085). OS was similar between the two groups (HR = 1.02; 95% CI, 0.86 to 1.22). The incidence of grade 3 or 4 adverse events were similar (78% v 72%), although a higher incidence of hand-foot syndrome (24% v 0%) and mucositis/stomatitis (12% v 1%) were observed in the PLD-docetaxel combination. Protocol-defined left ventricular ejection fraction decreases and congestive heart failure were reported in 5% and 1% in both treatment arms, respectively.

CONCLUSION

The PLD-docetaxel combination was more effective than docetaxel alone in women with metastatic breast cancer who had experienced relapse at least 1 year after prior adjuvant anthracycline therapy without an increase in cardiac toxicity, although mucocutaneous toxicity was more common.

Double-Blind, Placebo-Controlled Study of Quality of Life, Hematologic End Points, and Safety of Weekly Epoetin Alfa in Children With Cancer Receiving Myelosuppressive Chemotherapy

Purpose

To evaluate the effects of once-weekly epoetin alfa (EPO) on health-related quality of life (HRQOL), hemoglobin (Hb), transfusions, and tolerability in children with cancer.

Methods

Anemic patients 5 years to 18 years of age receiving myelosuppressive chemotherapy for nonmyeloid malignancies, excluding brain tumors, received intravenous EPO 600 units/kg to 900 units/kg or placebo once-weekly for 16 weeks. Patients and parents completed the pediatric health-related quality-of-life generic scales (GS) and cancer-specific scales (CS).

Results

One hundred eleven patients received EPO and 111 patients received placebo. Mean final values for GS total score (P = .763 among patients; P = .219 among parents) and CS domain scores (P ≥ .238; P ≥ .081, respectively) were not significantly different between treatment groups. EPO-treated patients had greater increases in Hb overall (P = .002) and were more likely to be transfusion free after 4 weeks (38.7% v 22.5%; P = .010). Change in Hb was correlated with change in PedsQL-GCS total score in the EPO group (r = 0.242; P = .018), but was not in the placebo group (r = 0.086; P = .430). Adverse events were comparable between treatment groups.

Conclusion

This study confirmed the tolerability and hematologic benefits of once-weekly EPO in children with cancer. No significant difference in HRQOL was detected between treatment groups, but a significant positive correlation was observed between Hb changes and HRQOL changes in the EPO group. Additional studies are warranted to assess HRQOL when anemia is managed optimally in children with cancer.

Chlamydia pneumoniae and acute chest syndrome in patients with sickle cell disease

PURPOSE Few studies address the association of Chlamydia pneumoniae infection with pulmonary disease and outcome in patients with underlying pathology such as sickle cell disease (SCD). SCD patients are susceptible to the pulmonary disorder known as acute chest syndrome (ACS), where the etiology remains ill defined. The purpose of this study was to analyze the clinical course and outcome of C. pneumoniae-associated ACS among SCD patients as part of the National Acute Chest Syndrome Study.

PATIENTS AND METHODS

This was a longitudinal study of SCD patients presenting with ACS to multiple U.S. medical centers. Two hundred ninety-six SCD patients who developed ACS were tested by PCR for C. pneumoniae and by standard techniques for other respiratory pathogens. These infections were evaluated for association with ACS, clinical course, and complications.

RESULTS

Forty-one (14%) patients with first episodes of ACS were PCR positive for C. pneumoniae. Compared with other infections, C. pneumoniae-infected patients were older, were more likely to present with chest pain, and had higher hemoglobin levels at diagnosis. Both groups had similar rates of respiratory failure and prolonged hospitalization. Of the 89 patients with single-pathogen infections, 27 (30%) were due to C. pneumoniae, 21% to Mycoplasma pneumoniae, 10% to RSV, 4% to Staphylococcus aureus, and 3% to Streptococcus pneumoniae.

CONCLUSIONS

C. pneumoniae was the most prevalent pathogen in this study of ACS and was responsible for significant morbidity. Additional research is required to develop effective treatment guidelines for ACS.

Central venous catheter use and the risk of infection in children with acute lymphoblastic leukemia: a report from the Children's Cancer Group

PURPOSE

To describe patterns of central venous catheter (CVC) use and determine the risk of infection associated with a catheter in children with acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Children with ALL (n = 1934), participating in Children's Cancer Group studies for good-prognosis ALL (CCG-1881) and intermediate-risk ALL (CCG-1891) were evaluated in a retrospective case-control study. The presence of a catheter and the occurrence of infectious complications were recorded after each treatment phase.

RESULTS

Young age and enrollment in the intermediate-risk study were associated with higher rates of catheter use. During each of the first four phases of therapy, the adjusted risk of infection was two- to fourfold higher when a catheter was in place. The proportion of patients with infection during the first four phases of therapy was 2.6 times higher with a CVC (14.4% versus 5.7%). Catheter use was associated with significantly increased hospitalization rates during induction, consolidation, and interim maintenance, but not during delayed intensification. A catheter did not significantly increase the risk of fever during neutropenia.

CONCLUSION

The presence of a CVC increases the risk of infection during the early phases of low-intensity therapy for ALL.

Effect of erythrocytapheresis on arterial oxygen saturation and hemoglobin oxygen affinity in patients with sickle cell disease

An important purpose of blood transfusion in patients with sickle cell disease is to improve arterial oxygen saturation (SaO2) and thereby reduce red cell sickling. To investigate the degree of improvement in SaO2 by blood transfusion, we determined the hemoglobin oxygen affinity, transcutaneous oxygen saturation (Tc-SO2), and pulse rate before and after automated partial exchange transfusion (erythrocytapheresis). In 13 patients with sickle cell disease who underwent 24 erythrocytapheresis procedures, the mean oxygen tension at half saturation (P50) was significantly reduced from 30.4 +/- 2.2 to 26.0 +/- 1.6 mm Hg (P< 0.01) immediately after exchange transfusion. Mean Tc-SO2 values increased from 96.2 +/- 2.8 to 98.5 +/- 2.1% (P< 0.01). Approximately 50% of the increase in Tc-SO2 after erythrocytapheresis could be explained by the increase in hemoglobin oxygen affinity. An increase in arterial oxygen pressure (PaO2) following erythrocytapheresis, suggested by the calculated PaO2 in this study, may explain some of the increase in Tc-SO2. We conclude that improvement in Tc-SO2 in patients with sickle cell disease resulted from changes in hemoglobin oxygen affinity as well as blood oxygen pressure following erythrocytapheresis.

Prolonged administration of granulocyte colony-stimulating factor (filgrastim) to patients with Fanconi anemia: a pilot study

This report examines the effect of filgrastim (granulocyte colony-stimulating factor, [G-CSF] in 12 patients with neutropenia [absolute neutrophil count [ANC] < 1,000/mm3]) caused by Fanconi anemia (FA). Two of 14 patients who were evaluated for study entry were ineligible because of unsuspected cytogenetic abnormalities in their bone marrow (BM). G-CSF was started at 5 micrograms/kg/d. All patients had an increase in their ANC at week 8 (mean increase = 15,664/mm3). The median ANC during therapy was 5,030/mm3. Eight of 10 patients who completed 40 weeks on study maintained an ANC > 1,500/mm3 on G-CSF given every-otherday. Four patients had an increase in their platelet count by week 8 without transfusion (maximum increase = 23,000 to 45,000/mm3); however, platelet counts fell toward baseline levels as the G-CSF dose was reduced. BM CFU-MK were increased at week 8 in three of four evaluable patients. Four patients who did not receive red blood cell transfusions had an increase in their hemoglobin level of at least 2.0 g/dL. A fifth patient had a red blood cell transfusion in week 2 and then had a similar increase in hemoglobin level without subsequent transfusion. Eight of 10 patients who completed 40 weeks of treatment showed increases in the percentage of BM CD34+ cells measured by flow cytometry. The same proportion showed increases in peripheral blood CD34+ cells. Increased BM cellularity and myeloid hyperplasia were constant findings and were associated with increased expression of the proliferating cell nuclear antigen. Adverse experiences were mild fever (1 patient) and a new BM cytogenetic abnormality at week 40 (1 patient). This study shows that prolonged administration of G-CSF exerts a stimulatory effect on the BM of FA patients and may be used to maintain a clinically adequate ANC in these patients. G-CSF has beneficial effects on multiple hematopoietic lineages in some patients and may be a good candidate for use in combination cytokine protocols for FA patients with progressive aplastic anemia. G-CSF use results in an increase in circulating CD34+ cells, a finding with important implications for future gene transfer protocols.

Predicting the risk of bacteremia in childen with fever and neutropenia

PURPOSE

We sought to identify factors assessable at the time of admission for fever and neutropenia that predict bacteremia in children with cancer.

PATIENTS AND METHODS

One hundred fifteen consecutive episodes of fever and absolute neutrophil count (ANC) less than 500/microliter in 72 children with cancer were studied prospectively to determine the risk of bacteremia using data assessable at the time of presentation. After exploratory analysis identified admission temperature and absolute monocyte count (AMoC) as the strongest predictive factors, recursive partitioning was used to determine cutpoints for these variables that resulted in discrimination between episodes associated with a lower or higher risk of bacteremia.

RESULTS

There were 24 episodes of bacteremia (21% of episodes). Episodes were grouped using the cutpoints for AMoC and temperature: 17% were classified as low risk for bacteremia (AMoC > or = 100/microliter), 65% as intermediate risk (AMoC < 100/microliter and temperature < 39.0 degrees C), and 18% as high risk (AMoC < 100/microliter and temperature > or = 39.0 degrees C). No episodes classified as low risk were associated with bacteremia; 19% of intermediate-risk and 48% of high-risk episodes were associated with bacteremia. The odds ratio of bacteremia for the high-risk versus the intermediate-risk group is 4.4 (95% confidence interval, 1.6 to 12.9). The risk classification was validated using data from 57 different episodes of fever and neutropenia treated in the same hospital.

CONCLUSION

Three levels of risk for bacteremia are defined using the AMoC and temperature at the time of admission for fever and neutropenia. Trials now should be conducted to test whether these factors may be used to assign some children to less intensive or outpatient antibiotic therapy at the time of presentation with fever and neutropenia.

A randomized, controlled trial of the efficacy of a heparin and vancomycin solution in preventing central venous catheter infections in children

OBJECTIVE

To determine whether adding vancomycin to central venous catheter (CVC) flush solution would significantly reduce the incidence of bacteremia attributable to luminal colonization with vancomycin-susceptible organisms.

STUDY DESIGN

Fifty-five children with cancer and eight children given total parenteral nutrition by the surgery or nutrition support services were randomly assigned to receive a heparin CVC flush solution (n = 31) or a heparin-vancomycin CVC flush solution (n = 32).

RESULTS

During 9158 catheter days, 6.5% of the patients in the heparin group and 15.6% of the patients in the heparin-vancomycin group had bacteremia attributable to luminal colonization with vancomycin-susceptible organisms (p = 0.43). The mean rates of bacteremia attributable to luminal colonization with vancomycin-susceptible organisms were 0.6/1000 catheter days in the heparin group and 1.4/1000 catheter days in the heparin-vancomycin group (p = 0.25). There was no significant difference between the groups when the time to the first episode of bacteremia attributable to luminal colonization with a vancomycin-susceptible organism was compared by means of Kaplan-Meier survival estimates. Streptococcus viridans infection was not attributable to luminal colonization.

CONCLUSION

The addition of vancomycin to heparin CVC flush solution did not reduce bacteremia with vancomycin-susceptible organisms. Bacteremia with Streptococcus viridans was not related to the use of a CVC.

A case-control retrospective study of the efficacy of granulocyte-colony-stimulating factor in children with neuroblastoma

PURPOSE

We conducted a retrospective case-control study to examine the effect of granulocyte-colony-stimulating factor (G-CSF) on the duration of the neutrophil nadir and other clinical parameters in children with neuroblastoma.

PATIENTS AND METHODS

We retrospectively reviewed 85 courses of the same chemotherapy in 16 consecutive neuroblastoma patients. The first nine patients received no growth factor and the following seven patients received G-CSF. Data obtained included days of neutropenia, fever rate and duration, hospitalization rate and duration, antibiotic duration, and infection rate.

RESULTS

Patients who received G-CSF had a significant decrease in the period of neutropenia (mean 5.4 +/- 2.6 days per course vs. 11.4 +/- 4.1 days per course in the control group; p < 0.001). There were no statistically significant differences in episodes of fever per course, rate of hospitalization per course, duration of hospitalization, or duration of antibiotic therapy. Control patients had documented infections during 16% (nine of 56) of their chemotherapy courses, whereas the patients receiving G-CSF had infections during 7% (two of 29) of their courses, but this difference was not statistically significant (p = 0.318). We calculated that a study of 220 courses in each group would be needed to have adequate power to confirm that this difference is statistically significant.

CONCLUSIONS

The administration of G-CSF in this patient population did result in fewer days of neutropenia, a finding that has been reported previously in several adult studies. However, we conclude that the clinical benefit of more rapid hematologic recovery in children remains uncertain and deserves further investigation in a large, prospective multicenter trial.

Treatment of refractory Evans syndrome with alternate-day cyclosporine and prednisone

PURPOSE

We report that the use of alternate-day cyclosporine and prednisone improved the clinical course of a 6-year-old child with severe Evans syndrome. Before the use of cyclosporine the child had experienced life-threatening episodes of hemolytic anemia despite the use of multiple therapeutic modalities.

METHODS

Cyclosporine was given at a dose of 10 mg/kg/day divided into two doses on alternate days.

RESULTS

The use of cyclosporine resulted in increased hemoglobin levels, increased platelet counts, and the reduction of the patient's prednisone dose from 2 mg/kg/day to as low as 1 mg/kg every other day. With this regimen, the patient had less severe hemolytic anemia, was less thrombocytopenic, and had fewer hospitalizations. No major toxic effects were associated with cyclosporine therapy.

CONCLUSION

The regimen of alternate-day cyclosporine and prednisone may prove to be useful in the treatment of other patients with refractory Evans syndrome.

Utilization of a pediatric emergency department by patients with sickle cell disease

When considering an alternative site to the emergency department (ED) for the care of acutely ill patients with sickle cell disease, it is necessary first to determine utilization of and satisfaction with ED care. Such data serve as guidelines for the planning and evaluation of alternative treatment facilities. We reviewed 137 consecutive ED visits by 98 patients with sickle cell diseases at The Children's Hospital of Philadelphia over a three-month period to determine ED utilization and waiting times. A follow-up telephone survey determined reasons for coming to the ED, duration of symptoms, and patient satisfaction with the ED visit. Our results reveal that an alternative facility open only during regular working hours would not serve the majority of patients with sickle cell disease. We describe the services provided to acutely ill sickle cell disease patients, and identify areas for improved service delivery within our ED or an alternative facility.

Pulse oximetry and factors associated with hemoglobin oxygen desaturation in children with sickle cell disease

The observation of low transcutaneous arterial oxygen saturation (SaO2) in otherwise well sickle cell patients has lead to questions about the interpretation of pulse oximetry values in these patients. We undertook a prospective study of children with sickle cell disease to (1) determine the prevalence of, and factors associated with, low transcutaneous SaO2 in clinically well patients, (2) develop an algorithm for the use of pulse oximetry in acutely ill patients, and (3) assess the accuracy of pulse oximetry in these patients. Eighty-six clinically well children with hemoglobin (Hb) SS had a lower mean transcutaneous SaO2 than 22 Hb SC patients and 10 control subjects (95.6% v 99.1% v 99.0%, respectively; p < .001). In Hb SS patients, a history of acute chest syndrome and age greater than 5 years were associated with lower transcutaneous SaO2 (mean 93.8% for those with a history of acute chest syndrome v 97.8% for those without a history of acute chest syndrome, and 94.0% for patients > 5 years old v 97.2% for those < or = 5 years old; P < .001). These associations were not seen in Hb SC patients. During acute illness, Hb SS patients with acute chest syndrome had transcutaneous SaO2 values that were less than 96% and at least 3 points lower than measurements made when they were well. A nomogram was designed to aid in the interpretation of transcutaneous SaO2 in acutely ill Hb SS patients when a comparison value is not available. The accuracy of pulse oximetry was shown by the correlation between SaO2 measured by pulse oximetry and calculated by using the patient's oxygen dissociation curve and PaO2 (r = .97). This study provides evidence that Hb oxygen desaturation is not a universal finding among children with sickle cell disease and identifies factors associated with Hb oxygen desaturation. We conclude that pulse oximetry may be useful to assess whether progressive pulmonary dysfunction begins at an early age in Hb SS patients, and to assess acutely ill patients for the presence of hypoxemia associated with acute chest syndrome.

Neurologic events after partial exchange transfusion for priapism in sickle cell disease

We describe six boys with homozygous sickle cell disease, aged 7 to 13 years, in whom acute, severe neurologic abnormalities developed 1 to 11 days after partial exchange transfusion was performed to treat priapism that was unresponsive to more conservative therapy. Hemoglobin levels were 10.5 to 13.4 gm/dl (mean 12.1 gm/dl), and hemoglobin S levels were 18% to 33% (mean 27%) before the onset of neurologic complications. Severe headache was the initial finding in five patients, four of whom had increased intracranial pressure and three of whom required tracheal intubation and hyperventilation. Four patients had seizures; three had focal neurologic deficits for more than 24 hours. Cerebral arteriography demonstrated vascular abnormalities, including irregularity, stenosis, and complete occlusion of vessels. Patients treated with regular erythrocyte transfusions had no recurrence of neurologic signs or symptoms when hemoglobin S levels were kept at 30% to 50%. The occurrence of serious neurologic complications after partial exchange transfusion in patients with homozygous sickle cell disease from three centers indicates the possibility of a causal relationship between the events. Early and thorough investigation of neurologic symptoms, especially severe headache, is warranted in this clinical setting.

Phosphorylation of the hepatic EGF receptor with cAMP-dependent protein kinase

The 170 000 dalton hepatic epidermal growth factor (EGF) receptor is phosphorylated on serine and tyrosine residues. The evidence indicates that distinct protein kinases are involved. Since EGF and agents that elevate cAMP are believed to participate in the regulation of liver regeneration, we tested whether or not the catalytic subunit of cAMP-dependent protein kinase (catalytic subunit), a known serine kinase, would utilize the EGF receptor as a substrate. The catalytic subunit increased phosphorylation of the EGF receptor in purified rat liver plasma membranes. The serine specificity of the catalytic subunit was established by phosphoamino acid analysis of electrophoretically purified EGF receptor. The result was confirmed by catalytic subunit phosphorylation of affinity purified preparations of the EGF receptor. The rates of dephosphorylation of the membrane-associated EGF receptor phosphorylated on different residues were compared. Dephosphorylation of serine residues (after catalytic subunit phosphorylation) was considerably slower (t1/2 greater than 120 sec) than the removal of phosphotyrosine after stimulation with EGF (t1/2 less than 30 sec).