Glomerular filtration rate estimation for carboplatin dosing in patients with gynaecological cancers

Background

Carboplatin remains integral for treatment of gynaecological malignancies and dosing is based on glomerular filtration rate (GFR). Measurement via radiotracer decay [nuclear medicine GFR (nmGFR)] is ideal. However, this may be unavailable. Therefore GFR is often estimated using formulae that have not been validated in patients with cancer and/or specifically for gynaecological malignancies, leading to debate over optimal estimation. Suboptimal GFR estimation may affect efficacy or toxicity.

Methods

We surveyed several UK National Health Service Trusts to assess carboplatin dosing practise. We then explored single-centre accuracy, bias and precision of various formulae for GFR estimation, relative to nmGFR, before validating our findings in an external cohort.

Results

Across 18 Trusts, there was considerable heterogeneity in GFR estimation, including the formulae used [Cockcroft–Gault (CG) versus Wright], weight adjustment and area under the curve (AUC; 5 versus 6). We analysed 274 and 192 patients in two centres. Overall, CamGFR v2 (a novel formula for GFR estimation developed at Cambridge University Hospitals NHS Foundation Trust) excelled, showing the highest accuracy and precision. This translated into accuracy of hypothetical carboplatin dosing; nmGFR-derived carboplatin dose fell within 20% of the Cam GFR v2-derived dose in 86.5% and 87% of patients across the cohorts. Among the CG formula and its derivatives, using adjusted body weight in those with body mass index ≥25 kg/m² [CG-adjusted body weight (CG-AdBW)] was optimal. The Wright and unadjusted CG estimators performed most poorly.

Conclusions

When compared with nmGFR assessment, accuracy, bias and precision varied widely between GFR estimators, with the newly developed Cam GFR v2 and CG-AdBW performing best. In general, weight (or body surface area)-adjusted formulae excelled, while the unadjusted CG and Wright formulae or the use of AUC6 (versus nmGFR AUC5) produced risk of significant overdose. Thus, individual centres should validate their GFR estimation methods. In the absence of validation, CG-AdBW or CamGFR v2 is likely to perform well while unadjusted CG/Wright formulae or AUC6 dosing should be avoided.

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Despite therapeutic advances, carboplatin is still used repeatedly for treatment of gynaecological cancers.

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Between centres, there is heterogenous use of GFR estimation methods for carboplatin dosing.

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The novel CamGFR v2 and CG-AdBW are the most accurate estimators.

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The Wright formula, unadjusted CG and the use of AUC6 with estimated GFR should all be avoided.

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If internal validation unavailable, centres should use CamGFR v2 or CG-AdBW for GFR estimation.

A phase I, dose escalation, pharmacodynamic, pharmacokinetic, and food-effect study of α2 integrin inhibitor E7820 in patients with advanced solid tumors

Introduction E7820 is an orally administered sulfonamide that inhibits alfa-2-integrin mRNA expression. Pre-clinically E7820 showed tumor anti-angiogenic effects in various tumor cell lines and xenograft mouse models. Human daily dosing of 100 mg QD had previously been shown to be safe and tolerable. Methods The study consisted of two parts: Part A (food effect) and Part B (determination of maximum tolerated dose (MTD) for bi-daily (BID) dosing). E7820 dosing started at 50 mg BID with planned escalation to 60, 80 and 100 mg BID every 28 days. Results Fifteen patients were enrolled in Part A and 26 in Part B. The most frequent adverse events of all grades were constipation, diarrhea, nausea, and fatigue while anemia, neutropenia, and fatigue were most frequent grade ≥3 toxicities. At dose-level 60 mg BID, two patients experienced dose-limiting toxicities (grade 3 neutropenic sepsis and grade 4 neutropenia). Therefore the recommended dose (RD) was 50 mg BID. Food had no effect on E7820 exposure. E7820 exposure following twice daily administration was dose-proportional. Expression of platelet integrin-α2 measured as a response biomarker in Part B, generally decreased by a median 7.7 % from baseline following treatment with 50 mg BID E7820. Reduction was most pronounced within 1-week post treatment. The median duration of treatment was median 54, range 20-111 days. The best overall response in any treatment group was stable disease (SD): 23.1 % in Part A (100 mg QD); at the RD 66.7 % (12 of 18 patients) and 40 % in the 60 mg BID group in Part B.

CONCLUSIONS

Food had no effect on E7820 exposure. A dose of 50 mg BID was considered the MTD. Treatment with E7820 is safe and tolerable with 2/3 of patients (66.7 %) at MTD having SD as their best response.

A randomised, placebo-controlled trial of weekly paclitaxel and saracatinib (AZD0530) in platinum-resistant ovarian, fallopian tube or primary peritoneal cancer†

BACKGROUND

We investigated whether the Src inhibitor saracatinib (AZD0530) improved efficacy of weekly paclitaxel in platinum-resistant ovarian cancer.

PATIENTS AND METHODS

Patients with platinum-resistant ovarian, fallopian tube or primary peritoneal cancer were randomised 2 : 1 to receive 8-week cycles of weekly paclitaxel (wPxl; 80 mg/m(2)/week ×6 with 2-week break) plus saracatinib (S; 175 mg o.d.) or placebo (P) continuously, starting 1 week before wPxl, until disease progression. Patients were stratified by taxane-free interval (<6 versus ≥6 months/no prior taxane). The primary end point was progression-free survival (PFS) rate at 6 months. Secondary end points included overall survival (OS) and response rate (RR).

RESULTS

A total of 107 patients, median age 63 years, were randomised. Forty-three (40%) had received >2 lines of prior chemotherapy. The 6-month PFS rate was 29% (wPxl + S) versus 34% (wPxl + P) (P = 0.582). Median PFS was 4.7 versus 5.3 months (hazard ratio 1.00, 95% confidence interval 0.65-1.54; P = 0.99). RR (complete + partial) was 29% (wPxl + S) versus 43% (wPxl + P), P value = 0.158. Grade 3/4 adverse events were 36% versus 31% (P = 0.624); the most frequent G3/4 toxicities were vomiting (5.8% saracatinib versus 8.6% placebo), abdominal pain (5.8% versus 0%) and diarrhoea (4.3% versus 5.7%). Febrile neutropenia was more common in the saracatinib arm (4.3%) than placebo (0%). Response, PFS and OS were all significantly (P < 0.05) better in patients with taxane interval ≥6 months/no prior taxane (n = 85) than those <6 months (n = 22), regardless of randomisation.

CONCLUSIONS

Saracatinib does not improve activity of weekly paclitaxel in platinum-resistant ovarian cancer. Taxane-free interval of ≥6 months/no prior taxane was associated with better outcome in both groups.

TRIALS REGISTRATION

Clinicaltrials.gov NCT01196741; ISRCTN 32163062.

A phase I study evaluating the pharmacokinetics (PK) and pharmacodynamics (PD) of the oral pan-phosphoinositide-3 kinase (PI3K) inhibitor GDC-0941

3538

Background: The PI3K-PTEN-AKT signaling pathway is deregulated in a wide variety of cancers. GDC-0941 is a potent and selective oral inhibitor of class I PI3K and demonstrates activity in a broad range of preclinical models (breast, ovarian, lung, and prostate). Methods: Patients (pts) with histologically confirmed advanced solid tumors and ECOG PS 0–1 were treated with GDC-0941 using a 3+3 escalation design at a single institution. Treatment was a single dose with 1wk washout, followed by GDC-0941 qd on a 3wk on, 1wk off schedule. Objectives were to determine MTD and DLT, evaluate PD endpoints in surrogate (pAKT in platelet rich plasma) and tumor (pAKT and pS6 in paired tumor biopsies and FDG uptake via PET imaging) tissues, and describe anti-tumor activity. Results: Thirteen patients have been enrolled in 4 successive cohorts (15–60 mg qd). GDC-0941 was generally well-tolerated with no drug related Grade 3 or 4 AEs or DLTs to date. Grade 1 diarrhea, nausea, dysgeusia, peripheral sensory neuropathy, dry mouth, thrombocytopenia, and increased aspartate aminotransferase have been observed. Preliminary PK data suggest dose-proportional increases in fasting mean Cmax and AUC. Preliminary PD data show decreased levels of pAKT in platelet rich plasma correlated with GDC-0941 plasma concentrations. GDC-0941 effects on FDG-PET imaging is being assessed, with 1 patient with HER2+ metastatic breast cancer showing a reduction in FDG uptake and improvement of a chest wall lesion (dose level 60 mg qd). Evaluation of PI3K pathway modulation from paired tumor biopsies is underway. Conclusions: GDC-0941 is generally well tolerated when administered qd at doses associated with inhibition of pAKT in surrogate tissues. Evidence of PD activity in tumor tissue has also been observed. Dose-escalation continues and updated PK/PD data will be presented.

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A phase I study of AT9283, an aurora kinase inhibitor, in patients with refractory solid tumors

2566

Background: AT9283, a multitargeted kinase inhibitor, inhibits several closely related tyrosine and serine/threonine kinases with an IC50 of <10 nM including Aurora A and B, JAK and ABL. Exposure of solid tumour cell lines to AT9283 in vitro induces an “aurora inhibitory” phenotype. Cell survival decreases with increased duration of exposure. Methods: A phase I dose escalation study was performed using a 72 hour continuous intravenous (iv) infusion schedule repeated three weekly according to a stand ard “3+3” design. Results: Thirty-three patients have been treated with a median age of 61 (range 33 to 76 years). The maximum tolerated dose (MTD) was 9 mg/m2/day. Treatment was well tolerated with febrile neutropenia the only dose limiting toxicity. Other adverse events considered possibly related to AT9283 were reversible and included gastrointestinal disturbance and fatigue. Biological evidence of aurora B inhibition manifest as a reduction in histone H3 phosphorylation in skin biopsies during the infusion was observed at all dose levels. A plateau steady state plasma concentration of AT9283 was achieved within 24 hours of initiating drug infusion at all dose levels and exposure increased linearly with dose. Seven patients received an initial oral dose of AT9283 as an aqueous solution in a fasting state at a dose of 0.9 mg mg/m2 one week prior to starting iv treatment. Interim pharmacokinetic analysis indicated that the median oral bioavailability was 27% (range 17 to 45%) The best response to treatment was a partial response in one patient with NSCLC (ongoing). An additional 4 patients received at least six cycles of therapy (squamous cell carcinoma of the lung, adenocarcinoma of the esophagus and colorectal carcinoma [2]) with a best response of stable disease. Conclusions: The MTD of AT9283 when administered as a 72 hour continuous iv infusion was 9mg/m2/day. Febrile neutropenia is the dose limiting toxicity and evidence of anticancer activity was seen in heavily pre-treated patients.

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Preliminary results of an open-label phase I pharmacokinetic/pharmacodynamic study of JNJ26481585: Early evidence of antitumor activity

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Background: JNJ26481585 is a novel orally active pan-histone deacetylase inhibitor (HDACI) which showed potent antitumor efficacy in a wide range of animal tumor models. Methods: A 2-stage accelerated titration design Phase I trial was conducted to characterize safety, establish the maximum tolerated dose (MTD) and determine pharmacokinetics in patients (pts) with refractory solid tumors, of performance status <2 and with adequate hematologic, renal, hepatic and cardiac function. The drug was administered orally, once daily in 3 weekly cycles. Results: To date, 9 pts (median age 59; range 32–74) have been treated at 4 dose levels (DL): 2 (2 pts), 4 (2 pts), 8 (3 pts), and 12 (2 pts) mg. The median number of cycles administered was 2 (range 1–9). Dose-limiting toxicity was seen at 12mg (CTCAE Grade [G] 3 non-sustained ventricular tachycardia [VT] [1 pt] and G3 fatigue [1 pt]) and the 8mg cohort is being expanded. Other toxicity observed at 12mg comprised G2 palpitations with QT prolongation (1 pt), G2 anorexia (1 pt), G2 vomiting (1 pt) and G2 dysgeusia (1 pt). At 8mg, 1 pt on warfarin developed a G2 INR increase. Non-specific ECG changes were observed from the 2mg DL onwards. The drug was generally well tolerated up to 8mg. Exposure to JNJ26481585 increased proportionally over the 2 to 12mg dose range, with a constant metabolite/parent ratio (3.5 for Cmax; 7 for AUC). Two partial responses (PR) and one stable disease (SD) have been observed. PR occurred in 2 pts with metastatic melanoma treated at 12mg : one pt had a PR in visceral and complete response in subcutaneous melanoma metastases after 22 days of drug and has ongoing response 5 months after stopping treatment; the second pt had PR in lymph nodes and reduction of cutaneous lesions of melanoma. One non small cell lung cancer pt treated at 4mg showed SD for 9 cycles. Assessment of histone acetylation as a pharmacodynamic biomarker in peripheral blood lymphocytes and hair follicles is ongoing. Conclusions: JNJ26481585 is generally well tolerated at doses up to 8mg daily. Evidence of promising antitumor activity has been observed with 2 PR to date in patients with metastatic melanoma. The 8mg cohort is being expanded with increased cardiac monitoring. Other schedules may be explored in the future.

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