Phase I study of cediranib, an oral VEGFR inhibitor, in combination with selumetinib, an oral MEK inhibitor, in patients with advanced solid malignancies

PURPOSE

Targeting the vascular endothelial growth factor (VEGF) pathway improves progression free survival in multiple advanced malignancies but durable responses are uncommon. Inhibition of the VEGF pathway at multiple levels of signal transduction may improve clinical outcomes. Preclinical data with cediranib, an inhibitor of all 3 VEGF receptors, in combination with selumetinib, an inhibitor of MEK 1/2, demonstrated improved tumor control experimentally. This phase I trial was designed to test the two agents in combination to evaluate the tolerability, safety and assess disease response.

METHODS

Patients with advanced solid malignancies were enrolled into this phase I trial. Cediranib and selumetinib were dosed using a toxicity-adaptive isotonic design for the dose escalation/de-escalation of each agent. Both cediranib and selumetinib were administered daily and continuously. Cycles were 28 days in length.

RESULTS

Eighteen patients were enrolled. At all dose levels, dose limiting toxicities (DLT) were observed, which limited dose escalation and further evaluation. The maximum tolerated dose of cediranib and selumetinib in combination could not be determined. The best response of stable disease was observed in eight patients.

CONCLUSIONS

Cediranib and selumetinib in combination on a continuous schedule was not tolerable, with patients experiencing cardiovascular and other DLTs. Intermittent schedules may be needed to establish a safe and tolerable combination of cediranib and selumetinib.

Population pharmacokinetic and exposure simulation analysis for cediranib (AZD2171) in pooled Phase I/II studies in patients with cancer

AIMS

A population pharmacokinetic (PK) model was developed for cediranib to simulate cediranib exposure for different doses, including comedication with strong uridine glucuronosyl transferase/P-glycoprotein inducers such as rifampicin, in cancer patients.

METHODS

Plasma concentrations and covariates from 625 cancer patients after single or multiple oral cediranib administrations ranging from 0.5 to 90 mg in 19 Phase I and II studies were included in the analysis. Stepwise covariate modelling was used to develop the population PK model. The final model was used to simulate cediranib exposure in cancer patients to evaluate cediranib target coverage and the need for dose adjustment for covariates or coadministration with rifampicin.

RESULTS

A two-compartment model with sequential zero- and first-order absorption and first-order elimination adequately described the cediranib concentration-time courses. Body weight and age were identified as having statistically significant impact on cediranib PK, but only <21% impact on AUC and maximum concentrations. Simulated lower bounds of 90% prediction interval or median of unbound cediranib concentrations after cediranib 15 or 20 mg exceeded the IC₅₀ for vascular endothelial growth factor receptors-1, -2 and -3. Exposures of cediranib 20 or 30 mg with coadministration of rifampicin were comparable to those of 15 or 20 mg, respectively, without coadministration.

CONCLUSIONS

No covariate was identified to require dose adjustment for cediranib. Cediranib exposure following 15 or 20 mg daily dose administration is adequate overall for inhibition of in vitro estimated vascular endothelial growth factor receptor-1, -2 and -3 activities. An increase in cediranib dose may be needed for cediranib coadministered with strong uridine glucuronosyl transferase/P-glycoprotein inducers such as rifampicin.

VEGF inhibitors and prostate cancer therapy

Prostate cancer remains the most common non-cutaneous malignancy among American men. Since the advent of PSA testing, most men are diagnosed with localized disease, but a proportion of men will be diagnosed with metastatic disease, many will eventually receive chemotherapy with docetaxel and prednisone. However, responses are not durable and all men will ultimately progress on this treatment. As such, continued efforts are geared towards the discovery of new agents and mechanisms of targeting prostate cancer. Angiogenesis has been shown to play an important role in tumorigenesis, proliferation and metastasis in prostate cancer. Here we discuss the major angiogenic signaling pathway involving VEGF in prostate cancer progression and the role of various promising agents that targets this pathway. This includes bevacizumab, thalidomide and its analogues, tyrosine kinase inhibitors sorafenib and AZD2171, and other inhibitors of angiogenic signaling pathways. Results of key clinical trials associated with the use of these agents and future directions are discussed herein.