A Phase I, Open-Labeled, Single-Arm, Dose Escalation, Clinical and Pharmacology Study of Dichloroacetate (DCA) in Patients With Recurrent and/or Metastatic Solid Tumours
Dichloroacetate (DCA) is a small molecule that has been used for years to treat lactic acidosis and rare metabolic disorders in humans. Further testing now shows that it may suppress the growth of human cancer cells. Tests of DCA on human cells cultured outside of the body found that it killed lung, breast, and brain cancer cells, without affecting human normal cells. Tumors in rats that were infected with human tumors also shrank considerably. Most cancers are characterized by a resistance to apoptosis (cell death that removes abnormal cells) that makes them more likely to grow as well as be resistant to most cancer treatments. Plus, many current cancer treatments kill both cancerous and healthy cells and are highly toxic. DCA works by reversing the damage to the mitochondria that is present in cancer cells, thus reactivating the apoptosis (cell death) mechanism in them. The result is the death of the cancer cells. This mitochondrial reactivation presents an entirely new approach to treating cancer.
DCA is known to be relatively well tolerated with few significant side effects and its selectivity, effectiveness and ease of delivery (oral) make it an attractive opportunity. It is hoped that one day this treatment may become a safe and effective treatment, either along or in conjunction with other treatments, for many forms of cancer.
|Study Design:||Allocation: Non-Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||A Phase I, Open-Labeled, Single-Arm, Dose Escalation, Clinical and Pharmacology Study of Dichloroacetate (DCA) in Patients With Recurrent and/or Metastatic Solid Tumours|
- To assess safety and tolerability of oral DCA [ Time Frame: Trial Completion ] [ Designated as safety issue: Yes ]
- To determine the dose-limiting toxicity (DLT) and phase II dose [ Time Frame: Trial completion ] [ Designated as safety issue: Yes ]
- To characterize pharmacokinetic (PK) profile [ Time Frame: Trial Completion ] [ Designated as safety issue: Yes ]
- To evaluate the effect of oral DCA [ Time Frame: Trial Completion ] [ Designated as safety issue: Yes ]
- To evaluate the clinical response rate [ Time Frame: Trial completion ] [ Designated as safety issue: Yes ]
- To evaluate the change in standard uptake value by FDG-PET scans before and after treatment with DCA [ Time Frame: Trial completion ] [ Designated as safety issue: Yes ]
|Study Start Date:||December 2007|
|Estimated Study Completion Date:||May 2012|
|Estimated Primary Completion Date:||May 2012 (Final data collection date for primary outcome measure)|
As cancer cells have a hyperpolarized mitochondrial membrane and deficiency in Kv channel expression, it was postulated that the reversal of this observation may increase apoptosis and inhibit tumor growth. Bonnet and colleagues reported that the administration of DCA led to the switch from glycolysis to oxidative phosphorylation in the Krebs Cycle through inhibition of PDHK. This was associated with an increase in the production of reactive oxygen species and a decrease in hyperpolarization of the inner mitochondrial membrane, leading to efflux of proapoptotic proteins and apoptosis as measured by increased in TUNEL-positive cells. In addition, DCA also decreased the expression of survivin, an anti-apoptotic protein. DCA upregulated the expression of Kv channels in cancer cells, leading to efflux of potassium ions and further increased the proapoptotic effect of DCA. Such change in energy metabolism and apoptosis was not observed in normal cells. DCA was also shown to inhibit tumor growth both in vitro and in vivo. Thus, inhibition of PDHK by DCA represents a novel anti-cancer therapy target with reasonable toxicities to normal tissue. It is therefore of interest to study DCA in refractory cancer patients.
Although the bioavailability was only 50-60% in normal subjects treated with 2.5 microgram/kg of DCA , in a study using clinically relevant dose of DCA at 50 mg/kg, the bioavailability was 100% in health volunteers. DCA administered at 50 mg/kg/day can achieve plasma concentrations above those require for inhibition of PHDK, the target enzyme for at least 24 hours, without exceeding the concentration for maximal lactate lowering. There was a high incidence of peripheral neuropathy in adults with MELAS after administration of DCA at 50 mg/kg/day for 6 months, but peripheral neuropathy is part of the MELAS syndrome, and many adult patients with MELAS develop diabetes mellitus, which commonly presents with peripheral neuropathy. In the contrary, no peripheral neuropathy was observed in children with congenital acidosis after prolonged treatment with DCA at 50 mg/kg/day up to 2 years. Therefore, with exclusion of patients with any grade 2 or higher peripheral neuropathy and with careful monitoring of peripheral neuropathy using monofilaments, the likelihood of developing severe peripheral neuropathy in adult cancer patients should be minimized. Given the presence of significant neuropathy in adult patients with MELAS after treatment with DCA at 25 mg/kg/day, it is judged to be safe and reasonable to establish the starting dose at 12.5 mg/kg/day in adult cancer patients.
|Cross Cancer Institute|
|Edmonton, Alberta, Canada, T6G 1Z2|
|Principal Investigator:||Peter Venner, M.D.||Alberta Health Services|
|Principal Investigator:||Evangelos Michelakis, M.D.||University of Alberta|