Best practice for analysis of shared clinical trial data

Background

Greater transparency, including sharing of patient-level data for further research, is an increasingly important topic for organisations who sponsor, fund and conduct clinical trials. This is a major paradigm shift with the aim of maximising the value of patient-level data from clinical trials for the benefit of future patients and society. We consider the analysis of shared clinical trial data in three broad categories: (1) reanalysis - further investigation of the efficacy and safety of the randomized intervention, (2) meta-analysis, and (3) supplemental analysis for a research question that is not directly assessing the randomized intervention.

Discussion

In order to support appropriate interpretation and limit the risk of misleading findings, analysis of shared clinical trial data should have a pre-specified analysis plan. However, it is not generally possible to limit bias and control multiplicity to the extent that is possible in the original trial design, conduct and analysis, and this should be acknowledged and taken into account when interpreting results. We highlight a number of areas where specific considerations arise in planning, conducting, interpreting and reporting analyses of shared clinical trial data. A key issue is that that these analyses essentially share many of the limitations of any post hoc analyses beyond the original specified analyses. The use of individual patient data in meta-analysis can provide increased precision and reduce bias. Supplemental analyses are subject to many of the same issues that arise in broader epidemiological analyses. Specific discussion topics are addressed within each of these areas.

Summary

Increased provision of patient-level data from industry and academic-led clinical trials for secondary research can benefit future patients and society. Responsible data sharing, including transparency of the research objectives, analysis plans and of the results will support appropriate interpretation and help to address the risk of misleading results and avoid unfounded health scares.

Effect of treatment with epoetin Beta on thromboembolic events in anemic patients with cancer: a metaanalysis

PURPOSE

Epoetin therapy is associated with a slight increase in thromboembolic event (TEE) incidence, although causality is uncertain. This metaanalysis compared TEE incidence in patients with cancer-related anemia treated with epoetin beta versus a control group (placebo or standard treatment) and investigated the impact of hemoglobin (Hb) parameters on thromboembolic risk.

PATIENTS AND METHODS

Patients from 9 randomized trials were pooled (epoetin beta group, n = 800; control group, n = 613). Adverse event reports were reviewed for all TEEs recorded during treatment and 28 days thereafter. Thromboembolic event incidence was compared between 2 groups, and standard statistical analyses were conducted to investigate the potential of Hb parameters to modulate thromboembolic risk.

RESULTS

For epoetin beta, 5.9% of patients (n = 47) experienced >/= 1 TEE versus 4.2% of controls (n = 26; not significant).Thromboembolic-related mortality rates were 1% in both groups. Thromboembolic event rates in patients stratified by tumor type were consistent with the overall population. For epoetin beta, greater baseline-adjusted Hb area under the concentration-time curve and greater Hb increases during the first 4 weeks of treatment significantly correlated with reduced risk of TEEs. Conversely, treatment in those with higher baseline Hb levels was associated with increased TEE risk.

CONCLUSION

When administered in accordance with European Organization for Research and Treatment of Cancer guidelines, epoetin beta did not appear to be associated with increased thromboembolic risk. Although risk of TEEs might be marginally increased in patients with cancer treated with epoetin beta, there is no increased risk of thromboembolic mortality.

Perspectives on the use of adaptive designs in clinical trials. Part II. Panel discussion

In the midst of gaining more experience in pursuing scientifically sound approaches of adaptive designs in clinical trials, a panel discussion with international representatives from industry, academia, and regulatory agencies was held at the Basel Biometric Society Spring Conference, March 12, 2010. The goal was to develop some consensus among industry, government, and academic statisticians concerning requirements and methods for adaptive designs in clinical trials. In this paper, we summarize the panelists' perspectives given at that session.

Value of N-terminal brain natriuretic peptide as a prognostic marker in patients with CKD: results from the CREATE study

BACKGROUND AND OBJECTIVES

This study assessed plasma N-terminal prohormone brain natriuretic peptide (NT-proBNP) as a prognostic marker of cardiovascular risk in patients with chronic kidney disease stages 3-4 and anaemia treated with epoetin beta to two haemoglobin target ranges.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

Of 603 patients enrolled in the Cardiovascular Risk Reduction by Early Anaemia Treatment with Epoetin Beta (CREATE) trial (baseline creatinine clearance 15-35 mL/min; haemoglobin 11.0-12.5 g/dL), 291 were included in this sub-study. Patients received subcutaneous epoetin beta either immediately after randomisation (target 13.0-15.0 g/dL; Group 1), or after their haemoglobin levels had fallen < 10.5 g/dL (target 10.5-11.5 g/dL; Group 2). Chronic heart failure New York Heart Association class III-IV was an exclusion criterion. (ClinicalTrials.gov Identifier: NCT00321919)

RESULTS

Cardiovascular event rates were higher in patients with baseline NT-proBNP > 400 vs. ≤ 400 pg/mL (39 vs. 13 events; p = 0.0002). Dialysis was initiated in 68 vs. 42 patients with NT-proBNP > 400 vs. ≤ 400 pg/mL (p = 0.0003). Amongst patients with NT-proBNP > 400 pg/mL, there was no significant difference between treatment groups in risk of cardiovascular events (HR = 0.57; p = 0.08) or time to dialysis (HR = 0.65; p = 0.08). The overall interpretation of this substudy is, however, limited by its relatively small sample size which, together with low clinical event rates, result in a lack of statistical power for some analyses and should be viewed as being hypothesis-generating in nature.

CONCLUSIONS

In chronic kidney disease patients with mild-to-moderate anaemia, elevated baseline plasma NT-proBNP levels are associated with a higher risk of cardiovascular events and an accelerated progression towards end-stage renal disease.

Epoetin-beta treatment in patients with cancer chemotherapy-induced anaemia: the impact of initial haemoglobin and target haemoglobin levels on survival, tumour progression and thromboembolic events

BACKGROUND

Epoetin-beta is used to treat patients with cancer undergoing chemotherapy to alleviate the symptoms of anaemia, reduce the risk of blood transfusions and improve quality of life (QoL).

METHODS

This meta-analysis of all 12 randomised, controlled studies of epoetin-beta evaluated the impact of therapy at different Hb-initiation levels and to different target Hb levels on overall survival, tumour progression and thromboembolic events (TEE). An analysis of risk factors pre-disposing patients to TEEs under epoetin-beta therapy was also performed. A total of 2297 patients are included in the analysis.

RESULTS

Analyses based on various Hb-initiation levels indicate no detrimental impact on survival (HR 0.99; 95% CI 0.70, 1.40) and a favourable impact on disease progression (HR 0.73; 95% CI 0.57, 0.94) when epoetin-beta was used within its licensed indication (Hb initiation < or = 10 g dl(-1)) or the EORTC recommended level of 11 g dl(-1). An increased risk of TEEs is seen for all Hb-initiation level strata and a detrimental impact on survival is seen when initiating epoetin-beta therapy at Hb levels >11 g dl(-1). We observe no association between high target Hb levels (> or = 13 g dl(-1)) and an increased risk of mortality, disease progression or TEEs with epoetin-beta compared with control.

CONCLUSION

The results of this analysis indicate that epoetin-beta therapy has no detrimental impact on survival or tumour progression when initiated at Hb levels up to 11 g dl(-1). Furthermore, there is no evidence to suggest that high Hb values achieved during epoetin-beta therapy are associated with an increased mortality, disease progression or TEE rate.

What is the impact of antithrombotic therapy and risk factors on the frequency of thrombovascular events in patients with metastatic breast cancer receiving epoetin beta?

PURPOSE, PATIENTS AND METHODS: This retrospective analysis of the BRAVE study evaluated the impact of baseline risk factors and antithrombotic therapy on the risk of thrombovascular events (TVEs) in patients receiving epoetin compared to patients not receiving epoetin.

RESULTS

Baseline risk factors have a significant impact on TVE risk under epoetin therapy. More than 2 risk factors increased the risk of TVEs in patients receiving epoetin (hazard ratio [HR] 2.89, confidence interval [CI] 1.04-8.02, p value [p]=0.04). In patients on epoetin without antithrombotic therapy, the risk for TVEs was higher (HR 4.11, CI 1.37-12.4, p=0.01) compared to those who received antithrombotics (HR 1.37, CI 0.59-3.18, p=0.45).

CONCLUSIONS

Our analysis has identified several risk factors which may impact the risk of TVEs under epoetin therapy. These data suggest that antithrombotic therapy may have the potential to reduce the risk of TVEs under epoetin therapy. These findings are hypothesis-generating and need to be confirmed in a prospective, randomised study.

Effect of Once-Weekly Epoetin Beta on Survival in Patients With Metastatic Breast Cancer Receiving Anthracycline- and/or Taxane-Based Chemotherapy: Results of the Breast Cancer—Anemia and the Value of Erythropoietin (BRAVE) Study

Purpose

The Breast Cancer—Anemia and the Value of Erythropoietin (BRAVE) study evaluated whether epoetin beta would improve survival in patients with metastatic breast cancer (MBC).

Patients and Methods

BRAVE was an open-label, randomized, multicenter study in patients with MBC treated with anthracycline- and/or taxane-based chemotherapy. Patients (hemoglobin [Hb] < 12.9 g/dL) were randomly assigned (1:1) to epoetin beta 30,000 U subcutaneously once weekly or control for 24 weeks. The primary efficacy variable was overall survival. Secondary efficacy outcomes included progression-free survival, transfusion- and severe anemia–free survival, Hb response, safety, and quality of life (QoL).

Results

After 18 months of follow-up, 62 (27%) of 231 patients survived with epoetin beta therapy and 63 (27%) of 232 with control. No difference was detected in overall survival (hazard ratio [HR] = 1.07; 95% CI, 0.87 to 1.33, P = .522) or progression-free survival (HR = 1.07; 95% CI, 0.89 to 1.30, P = .448). There was a statistically significant benefit on transfusion- and severe anemia–free survival compared with control (HR = 0.59; P = .0097). Median Hb level increased with epoetin beta (11.7 g/dL at baseline to 13.3 g/dL at 24 weeks) but did not change with control (11.5 v 11.4 g/dL). Patients receiving epoetin beta experienced more thromboembolic events (TEEs) compared with controls (13% v 6%; P = .012) with no difference in serious TEEs (4% v 3%). Epoetin beta did not significantly improve QoL in this study where patients had a high baseline Hb value.

Conclusion

In patients with MBC receiving chemotherapy and initial Hb less than 12.9 g/dL, epoetin beta increased Hb. No difference was detected in overall survival. Because of its superiority design, this study cannot, however, exclude clinically important differences in survival with absolute certainty.

Effect of treatment with epoetin beta on short-term tumour progression and survival in anaemic patients with cancer: A meta-analysis

To assess the early effect of epoetin beta on survival and tumour progression in anaemic patients with cancer, data were pooled from nine randomised clinical trials comparing epoetin beta with placebo or standard care. Studies were not primarily designed to assess these end points. Follow-up was for treatment duration plus 4 weeks following therapy completion. All adverse events (AEs) were retrospectively reviewed blinded, for progression. Thromboembolic events were also assessed. Data analysis involved standard statistical tests. Overall, 1413 patients were included (epoetin beta, n=800; control, n=613; 56% haematological, and 44% solid). Median initial epoetin beta dose was 30 000 IU/week. Overall survival during months 0–6 was similar with epoetin beta and control (0.31 vs 0.32 deaths/patient-year). No increased mortality risk was seen with epoetin beta (relative risk (RR) 0.97, 95% CI: 0.69, 1.36; P=0.87). There was a significantly reduced risk of rapidly progressive disease for epoetin beta (RR 0.78, 95% CI: 0.62, 0.99; P=0.042). Epoetin beta was associated with a slightly higher frequency of thromboembolic events vs control (5.9% vs 4.2% of patients) but thromboembolic-related mortality was identical in both groups (1.1%). Epoetin beta provided a slight beneficial effect on tumour progression and did not impact on early survival or thromboembolic-related mortality.

Normalization of hemoglobin level in patients with chronic kidney disease and anemia

BACKGROUND

Whether correction of anemia in patients with stage 3 or 4 chronic kidney disease improves cardiovascular outcomes is not established.

METHODS

We randomly assigned 603 patients with an estimated glomerular filtration rate (GFR) of 15.0 to 35.0 ml per minute per 1.73 m2 of body-surface area and mild-to-moderate anemia (hemoglobin level, 11.0 to 12.5 g per deciliter) to a target hemoglobin value in the normal range (13.0 to 15.0 g per deciliter, group 1) or the subnormal range (10.5 to 11.5 g per deciliter, group 2). Subcutaneous erythropoietin (epoetin beta) was initiated at randomization (group 1) or only after the hemoglobin level fell below 10.5 g per deciliter (group 2). The primary end point was a composite of eight cardiovascular events; secondary end points included left ventricular mass index, quality-of-life scores, and the progression of chronic kidney disease.

RESULTS

During the 3-year study, complete correction of anemia did not affect the likelihood of a first cardiovascular event (58 events in group 1 vs. 47 events in group 2; hazard ratio, 0.78; 95% confidence interval, 0.53 to 1.14; P=0.20). Left ventricular mass index remained stable in both groups. The mean estimated GFR was 24.9 ml per minute in group 1 and 24.2 ml per minute in group 2 at baseline and decreased by 3.6 and 3.1 ml per minute per year, respectively (P=0.40). Dialysis was required in more patients in group 1 than in group 2 (127 vs. 111, P=0.03). General health and physical function improved significantly (P=0.003 and P<0.001, respectively, in group 1, as compared with group 2). There was no significant difference in the combined incidence of adverse events between the two groups, but hypertensive episodes and headaches were more prevalent in group 1.

CONCLUSIONS

In patients with chronic kidney disease, early complete correction of anemia does not reduce the risk of cardiovascular events. (ClinicalTrials.gov number, NCT00321919 [ClinicalTrials.gov].).

Epoetin beta (NeoRecormon) therapy in patients with solid tumours receiving platinum and non-platinum chemotherapy: a meta-analysis

BACKGROUND

Anaemia is a common complication of chemotherapy (CT), including both non-platinum (Pt)-based as well as Pt-based CT.

PATIENTS AND METHODS

Patients from three controlled trials with solid tumours receiving either Pt- or non-Pt-based CT, who had been randomised to epoetin beta treatment or standard care, were included in this meta-analysis (n=255, n=199, respectively), to see if epoetin beta was equally effective in both CT types. The primary endpoint was haemoglobin (Hb) change. Secondary end-points included transfusion requirement, adverse events (AEs), survival, time to tumour progression and thromboembolic events (TEEs).

RESULTS

All patients responded rapidly to epoetin beta treatment, showing a median Hb increase of > or = 1 g/dl from baseline at week 4. A median Hb of 12.2, 12.5 and 11.8 g/dl was achieved in all patients, those receiving Pt-based CT and those receiving non-Pt-based CT, respectively, after 16 weeks of treatment. Transfusion risk reductions associated with epoetin beta treatment of 53% (p<0.0001), 61% (p<0.0001) and 26% (non significant) were observed for all patients, Pt- and non-Pt-based CT patients, respectively. Overall, for all three populations, there were no risks identified for tumour progression or overall survival. There was a statistically non-significant incidence of TEEs (5.9% versus 4.5%) and no marked differences were observed between groups for frequency or type of AEs reported.

CONCLUSION

The type of CT has no impact on the ability of epoetin beta to rapidly increase Hb in patients with solid tumours and CT-induced anaemia.

Population pharmacokinetics and concentration-effect relationships of capecitabine metabolites in colorectal cancer patients

AIMS

To assess the relationship between systemic exposure to capecitabine metabolites and parameters of efficacy and safety in patients with advanced or metastatic colorectal cancer from two phase III studies.

METHODS

Concentration-effect analyses were based on data from 481 patients (248 males, 193 females; age range 27-86 years) in two phase III studies. Plasma concentration-time data for 5'-deoxy-5-fluorouridine (5'-DFUR), 5-fluorouracil (5-FU) and alpha-fluoro-beta-alanine (FBAL) were obtained from sparse blood samples collected within the time windows 0.5-1.5 h, 1.5-3.0 h, and 3.0-5.0 h after capecitabine administration (1250 mg m(-2)) on the first day of cycles 2 (day 22) and 4 (day 64), respectively. Systemic exposure based on plasma concentrations of capecitabine and its metabolites was determined using individual parameter estimates derived from a population pharmacokinetic model constructed for this purpose in NONMEM. Logistic regression analysis was conducted for selected safety parameters (all treatment-related grade 3-4 adverse events, treatment-related grade 3-4 diarrhoea, grade 3 hand-foot syndrome (HFS) and grade 3-4 hyperbilirubinaemia) and for tumour response. Cox regression analysis was used for the analysis of time-to-event data (time to disease progression and duration of survival).

RESULTS

Statistically significant relationships between covariates and PK parameters were found as follows. A doubling of alkaline phosphatase activity was associated with a 11% decrease in 5-FU clearance and a 12% increase in its AUC. A 50% decrease in creatinine clearance was associated with a 35% decrease in FBAL clearance, a 53% increase in its AUC, a 24% decrease in its volume of distribution, and a 41% increase in its Cmax. A 30% increase in body surface was associated with a 24% increase in the volume of distribution of FBAL and a 19% decrease in its Cmax. There was a broad overlap in systemic drug exposure between patients regardless of the occurrence of treatment-related grade 3-4 adverse events or response to treatment, leading to weak relationships between systemic exposure to capecitabine metabolites and the safety and efficacy parameters. Of 42 concentration-effect relationships investigated, only five achieved statistical significance. Thus, we obtained a positive association between the AUC of FBAL and grade 3-4 diarrhoea (P = 0.035), a positive association between the AUC of 5-FU and grade 3-4 hyperbilirubinaemia (P = 0.025), a negative association between the Cmax of FBAL and grade 3-4 hyperbilirubinaemia (P = 0.014), a negative association between the AUC of 5-FU (in plasma) and time to disease progression (hazard ratio (HR) = 1.626, P = 0.0056), and a positive association between the Cmax of 5'-DFUR and survival (HR = 0.938, P = 0.0048). Additionally, there were inconsistencies when concentration-effect relationships were compared across the two studies.

CONCLUSIONS

Systemic exposure to capecitabine and its metabolites in plasma is poorly predictive of safety and efficacy. The present results have no clinical implications for the use of capecitabine and argue against the value of therapeutic drug monitoring for dosage adjustment.

Randomized, open-label, phase II trial of oral capecitabine (Xeloda) vs. a reference arm of intravenous CMF (cyclophosphamide, methotrexate and 5-fluorouracil) as first-line therapy for advanced/metastatic breast cancer

BACKGROUND

Oral capecitabine was evaluated in terms of overall response rate, safety, and tolerability as first-line therapy in women aged > or = 55 years with advanced/metastatic breast cancer.

PATIENTS AND METHODS

Ninety-five patients were randomized (2:1) to either intermittent oral capecitabine 1,255 mg/m2 twice daily (two weeks' treatment followed by a one-week rest period) or intravenous CMF (cyclophosphamide. methotrexate, 5-fluorouracil [5-FU]) administered every three weeks.

RESULTS

The overall response rate in the capecitabine group was 30% (95% confidence interval (95% CI): 19%-43%), including three complete responses (5%). The response rate observed in the CMF group was 16% (95% CI: 5%-33%), with no complete responses. Median time to disease progression was 4.1 months with capecitabine and 3.0 months with CME. Survival was similar in the two treatment groups (median 19.6 months with capecitabine. 17.2 months with CMF). The safety profiles were different for capecitabine and CMF. However, both regimens were generally well tolerated and treatment interruption and/or dose modification was effective in managing toxicities associated with capecitabine. Alopecia and myelosuppression were rare in patients receiving capecitabine while diarrhea and hand-foot syndrome were more common. Treatment interruption and/or individual dose adjustment of capecitabine was required in 34% of patients and was generally effective in managing adverse events. Treatment was stopped owing to toxicity in 16% of patients in the capecitabine arm. The incidence of deaths during or within 28 days of stopping study treatment was 8% and 6% in the capecitabine and CMF arms, respectively.

CONCLUSIONS

An oral, twice-daily regimen of capecitabine is effective and well tolerated when used as first-line chemotherapy in older patients (> or = 55 years) with advanced/metastatic breast cancer, and is suitable for outpatient therapy.

Comparison of oral capecitabine versus intravenous fluorouracil plus leucovorin as first-line treatment in 605 patients with metastatic colorectal cancer: results of a randomized phase III study

PURPOSE

To compare the response rate, efficacy parameters, and toxicity profile of oral capecitabine with bolus intravenous (IV) fluorouracil plus leucovorin (5-FU/LV) as first-line treatment in patients with metastatic colorectal cancer.

PATIENTS AND METHODS

We prospectively randomized 605 patients to treatment with oral capecitabine for 14 days every 3 weeks or 5-FU/LV by rapid IV injection daily for 5 days in 4-week cycles.

RESULTS

The overall objective tumor response rate among all randomized patients was significantly higher in the capecitabine group (24.8%) than in the 5-FU/LV group (15.5%; P =.005). In the capecitabine and 5-FU/LV groups, median times to disease progression were 4.3 and 4.7 months (log-rank P =.72), median times to treatment failure were 4.1 and 3.1 months (P =.19), and median overall survival times were 12.5 and 13.3 months (P =.974), respectively. Capecitabine, compared with bolus 5-FU/LV treatment, produced a significantly lower incidence (P <.0002) of diarrhea, stomatitis, nausea, and alopecia. Patients treated with capecitabine also displayed lower incidences of grade 3/4 stomatitis and grade 3/4 neutropenia (P <.0001) leading to significantly less neutropenic fever/sepsis. Grade 3 hand-foot syndrome (P <.00001) and grade 3/4 hyperbilirubinemia were the only toxicities more frequently associated with capecitabine than with 5-FU/LV treatment.

CONCLUSION

Oral capecitabine was more active than 5-FU/LV in the induction of objective tumor responses. Time to disease progression and survival were at least equivalent for capecitabine compared with the 5-FU/LV arm. Capecitabine also demonstrated clinically meaningful benefits over bolus 5-FU/LV in terms of tolerability.

Capecitabine, an oral fluoropyrimidine carbamate with substantial activity in advanced colorectal cancer: results of a randomized phase II study

PURPOSE

To evaluate in patients with advanced colorectal cancer (CRC) three treatment regimens of oral capecitabine in order to select the most appropriate regimen for testing in phase III.

PATIENTS AND METHODS

Three capecitabine schedules were evaluated in a randomized phase II design: arm A, 1,331 mg/m(2)/d bid continuously; arm B, 2,510 mg/m(2)/d bid intermittently (2 weeks on/1 week off); and arm C, 1,657 mg/m(2)/d plus oral leucovorin 60 mg/d bid intermittently (2 weeks on/1 week off).

RESULTS

One hundred nine patients were randomized; 39 patients were assessable for efficacy in arm A, 34 in arm B, and 35 in arm C. Patient characteristics were balanced in the arms. Confirmed tumor responses (partial response [PR] + complete response [CR]) were reported for eight patients with two CRs (21%; 95% confidence interval [CI], 9% to 36%) in arm A, eight patients with one CR (24%; 95% CI, 11% to 41%) in arm B, and eight patients with two CRs (23%; 95% CI, 10% to 40%) in arm C. Median times to progression (TTP) in arms A, B, and C were 127, 230, and 165 days, respectively. Overall, more toxicity was seen with capecitabine plus leucovorin, particularly diarrhea and hand-foot syndrome. There was no grade 3 or 4 marrow toxicity.

CONCLUSION

Capecitabine offers a new, effective treatment option as an oral single agent in advanced CRC. Promising overall response rates were reported for all three regimens. The addition of leucovorin to the intermittent regimen had no marked effect on tumor response or median TTP. The intermittent single-agent capecitabine schedule is proposed for phase III evaluation, based on considerations of toxicity, dose-intensity, response rate, and TTP.

Phase I and pharmacokinetic study of the oral fluoropyrimidine capecitabine in combination with paclitaxel in patients with advanced solid malignancies

PURPOSE

To evaluate the feasibility of administering the oral fluoropyrimidine capecitabine in combination with paclitaxel, to characterize the principal toxicities of the combination, to recommend doses for subsequent disease-directed studies, and to determine whether significant pharmacokinetic interactions occur between these agents when combined.

PATIENTS AND METHODS

Sixty-six courses of capecitabine and paclitaxel were administered to 17 patients in a two-stage dose-escalation study. Paclitaxel was administered as a 3-hour intravenous (IV) infusion every 3 weeks, and capecitabine was administered continuously as two divided daily doses. During stage I, capecitabine was escalated to a target dose of 1,657 mg/m(2)/d, whereas the paclitaxel dose was fixed at 135 mg/m(2). In stage II, paclitaxel was increased to a target dose of 175 mg/m(2), and the capecitabine dose was the maximum established in stage I. Pharmacokinetics were characterized for each drug when given alone and concurrently.

RESULTS

Myelosuppression, predominately neutropenia, was the principal dose-limiting toxicity (DLT). Other toxicities included hand-foot syndrome, diarrhea, hyperbilirubinemia, skin rash, myalgia, and arthralgia. Two patients treated with capecitabine 1,657 mg/m(2)/d and paclitaxel 175 mg/m(2) developed DLTs, whereas none of six patients treated with capecitabine 1,331 mg/m(2)/d and paclitaxel 175 mg/m(2) developed DLTs during course 1. Pharmacokinetic studies indicated that capecitabine and paclitaxel did not affect the pharmacokinetic behavior of each other. No major antitumor responses were noted.

CONCLUSION

Recommended combination doses of continuous capecitabine and paclitaxel are capecitabine 1,331 mg/m(2)/d and paclitaxel 175 mg/m(2)/d IV every 3 weeks. Favorable preclinical mechanistic interactions between capecitabine and paclitaxel, as well as an acceptable toxicity profile without clinically relevant pharmacokinetic interactions, support the performance of disease-directed evaluations of this combination.

Multicenter phase II study of capecitabine in paclitaxel-refractory metastatic breast cancer

PURPOSE

Capecitabine is a novel, oral, selectively tumor-activated fluoropyrimidine carbamate. This large multicenter phase II trial tested the efficacy and safety of twice-daily oral capecitabine at 2,510 mg/m2/d given for 2 weeks followed by a 1-week rest period and repeated in 3-week cycles, in patients with paclitaxel-refractory metastatic breast cancer.

PATIENTS AND METHODS

Patients were to have received at least two but not more than three prior chemotherapeutic regimens, one of which had to have contained paclitaxel given for metastatic disease. One hundred sixty-three patients were entered onto the study at 25 centers, and 162 patients received capecitabine. One hundred thirty-five patients had bidimensionally measurable disease, and 27 patients had assessable disease.

RESULTS

The overall response rate was 20% (95% confidence interval, 14% to 28%). All responding patients were resistant to or had failed paclitaxel, and all had received an anthracycline. Three complete responses were seen, with complete response durations of 106, 109, and 194+ days. Median duration of response was 8.1 months, median survival time was 12.8 months, and the median time to disease progression was 93 days. The most common treatment-related adverse events were hand-foot syndrome, diarrhea, nausea, vomiting, and fatigue. Diarrhea (14%) and hand-foot syndrome (10%) were the only treatment-related adverse events that occurred with grade 3 or 4 intensity in more than 10% of patients.

CONCLUSION

Capecitabine is an active drug in the treatment of paclitaxel-refractory metastatic breast cancer. It has a favorable toxicity profile with the added advantage of being an oral drug administered at home.

Safety and activity of saquinavir in HIV infection

We evaluated saquinavir, an orally active, selective inhibitor of HIV proteinase, in a randomised, double-blind, dose-ranging study in 49 zidovudine-naive HIV-positive patients with few or no symptoms and CD4 cell counts of 500 or less. The study was designed to assess the antiviral activity and tolerability of saquinavir. Patients were randomised to receive 25, 75, 200, or 600 mg of saquinavir three times daily for 16 weeks. No serious adverse events occurred. CD4 cell counts showed a trend indicative of a dose response in favour of the 600 mg dosage, the maximum increase being seen around week 4. In none of the 8 patients with positive plasma viraemia at baseline did cultures become negative after treatment; peripheral blood mononuclear cell and plasma-viral load by culture and DNA and RNA PCR all showed a trend towards reduction at higher doses of saquinovir. Saquinavir was well tolerated in this group of previously untreated patients with few or no symptoms; this study shows that an HIV-proteinase inhibitor is active in HIV-infected patients.

Erythropoietin in polycystic kidneys

Erythropoietin (EPO) formation in kidneys of 18 patients with autosomal dominant polycystic kidney disease (ADPKD) was investigated. In 12 patients on hemodialysis and in 6 patients with preterminal renal failure serum, EPO was 29 +/- 7 and 16 +/- 1.5 mU/ml and hemoglobin concentrations were 11.0 +/- 0.6 and 12.7 +/- 1.2 g/dl, respectively. Cyst fluid from a total of 357 renal cysts was obtained by either in vivo aspiration or immediately after nephrectomy. The cysts contained variable concentrations of bioactive EPO from undectable values up to 3.2 U/ml. A pronounced enrichment of EPO was observed in cysts with sodium concentrations greater than 100 mmol/liter, suggesting an association with proximal tubular malformations. The EPO concentrations in the cysts were neither correlated with the protein concentration nor with the oxygen pressure of the cyst fluid. Using a cDNA probe for human EPO, mRNA for EPO was localized in stroma cells of the cyst walls by an in situ hybridization technique. Our findings suggest that single interstitial cells juxtaposed to proximal tubular cysts may produce EPO independent of the oxygen pressure inside the cysts, which ameliorates the anemia during end-stage polycystic kidney disease.