**5.3.24 3,4-Diaminopyridine (DAP)**

The potassium channel blocker DAP did not show a benefit in ALS patients (Aisen et al., 1996; Aisen et al., 1995). Currently, the drug is re-evaluated after a phase I safety study (Bertorini et al., 2011).

### **5.3.25 Dronabinol**

Dronabinol is a synthetic Δ9-tetrahydrocannabinol (Delta-9-THC, Δ9-THC, THC).

It has been tested in a phase II study (NCT00812851) in ALS patients suffering from muscular cramps, where no subjective improvement of cramp intensity has been seen (Weber et al., 2010).

### **5.3.26 Edaravone (MCI-186; NSC 2629)**

Edavarone is an anti-oxidant free radical scavenger (Takahashi, 2009).

It has been tested in several phase II/III clinical trials (NCT00330681, NCT00415519, NCT00424463) for safety and efficacy. A phase II study found a possible delay in the progression of functional motor symptoms in ALS patients (Yoshino & Kimura, 2006).

### **5.3.27 Erythropoietin (EPO)**

EPO is a hematopoietic growth factor with neuroprotective properties (Maurer et al., 2008). Moreover, EPO exhibited anti-inflammatory and anti-apoptotic effects.

It has been evaluated in a phase II trial, finding no effects on survival and functional outcome (Lauria et al., 2009).
