Pharmacokinetics of Regional Therapy: Isolated Limb Infusion and Other Low Flow Techniques for Extremity Melanoma

Challenges in chemotherapy delivery: comparison of standard chemotherapy delivery to locoregional vascular mass fluid transfer

Standard intravenous chemotherapy delivery to neoplasms relies on simple diffusion gradients from the intravascular to the interstitial space. Systemic perfusion creates untoward effects on normal tissue limiting both concentration and exposure times. Regional intra-arterial therapy is limited by drug recirculation and vascular isolation repeatability and does not address the interstitial microenvironment. Barriers to delivery relate to chaotic vascular architecture, heterogeneous fluid flux, increased interstitial and variable solid tumor pressure and ischemia. To address these difficulties, a delivery system was developed allowing mass fluid transfer of chemotherapeutic agents into the interstitium. This implantable, reusable system is comprised of multiple independently steerable balloons and catheters capable of controlling the locoregional hydraulic and oncotic forces across the vascular endothelium.

Surgical versus percutaneous isolated pelvic perfusion (IPP) for advanced melanoma: comparison in terms of melphalan pharmacokinetic pelvic bio-availability

BACKGROUND

Isolated pelvic perfusion (IPP) can be used to treat unresectable melanoma metastases of the pelvis. IPP can be performed either by surgical or percutaneous approaches, using different balloon catheters. The aim of this study was to examine whether the surgical and percutaneous approaches were comparable with respect to tumor drug exposure in the pelvis.

METHODS

A pharmacokinetic study was performed in 5 melanoma patients treated with surgical IPP and five with percutaneous IPP. Both groups received melphalan at the dose of 30 mg/m2. Melphalan pharmacokinetic analyses were performed and the main parameter used to evaluate pelvic tumor drug-exposure was the ratio of areas under the melphalan plasma concentration curves in the pelvis and the systemic compartment, during the perfusion time (AUC0 to 20). Non-parametric Mann-Whitney tests were employed for statistical comparisons.

RESULTS

The median and interquartile range (IQR) values of the ratios between melphalan AUC0 to 20 in pelvic and systemic compartments were 7.9 (IQR 7.2 to 9.9) and 5 (IQR 4 to 7.9) for surgical and percutaneous IPPs, respectively (p = 0.209).

CONCLUSIONS

Tumor exposure to drug using these two methods did not statistically differ and both methods, therefore, can be adopted interchangeably, utilizing a perfusion blood flow rate of approximately 120 ml/min. The small sample size is a limitation of this study but our preliminary results can be used to calculate the effect size of a larger trial. Trial Registration Clinical Trials.gov Identifier NCT01920516; date of trial registration: August 6, 2013.

Isolated limb infusion with melphalan and actinomycin D in melanoma patients: factors predictive of acute regional toxicity

IMPORTANCE OF THE FIELD

Isolated limb infusion (ILI) is a simple, minimally invasive technique of delivering high concentrations of cytotoxic drugs to a diseased limb for achieving disease control in that limb. Recent studies have suggested that mild hyperthermic (38 degrees C) ILI might be the best initial treatment for extensively recurrent limb melanoma given its simplicity, low morbidity and a complete response rate of 30 - 40%.

AREAS COVERED IN THIS REVIEW

Since 1994 when ILI was first described by Thompson et al., the procedure has been adopted by several centres around the world; research and improvements in the technique have resulted in reduction in limb toxicity without reducing its clinical efficacy. The pharmacokinetics of melphalan and the clinical efficacy and adverse effects of ILI from various centres are summarised. Minor but possibly important differences in the ILI techniques used in different institutions may be important in improving its efficacy and reducing the toxic effects.

WHAT THE READER WILL GAIN

An understanding of the efficacy and toxicity associated with ILI with cytotoxic drugs in melanoma patients and of methods to optimise regional therapy for malignant disease in a limb.

TAKE HOME MESSAGE

ILI with mild hyperthermia (38 degrees C) is well tolerated with tumour remission rates in melanoma patients similar to those achieved by isolated limb perfusion. Mild (grade I - II) and moderate/severe (grade > or = III) limb toxicities occur in 58 - 68% and 32 - 41% of patients, respectively, but long-term morbidity is rare. A high peak and high final melphalan concentration in the infusate, the AUC of melphalan concentration in the infusate and an increased postoperative serum creatine phosphokinase concentration are factors predictive of acute regional toxicity. Drug dose adjusted for ideal body weight and gender may reduce acute toxicity following ILI. It has been suggested that the use of papaverine prior to the infusion of melphalan might increase its efficacy, but it may also increase toxicity. Large prospective studies are needed to more accurately define the perioperative factors that influence acute regional toxicity after ILI and to establish strategies to optimise clinical outcome.