Abstracts

RATIONALE: Controlled prospective AE drug trials, predominantly analyse responder rates. Tolerability is rarely counted as an exit event. But in clinical practice long term drug therapy is determined by efficacy and tolerability.
The survival rate (number of patients, still on the drug after a period of time) is discussed to be a good indicator of the clinical benefit of a drug, including both aspects.
METHODS: We studied retrospectively outcome, adverse events and survival rates (Kapplan-Meyer) after 6 and 12 months of 205 patients on Levetiracetam (LEV), 227 patients on Topiramate (TPM) and 168 patients on Oxcarbacepine (OXC) add on therapy.
RESULTS: On LEV there were 49 % responder (at least 50 % seizure reduction) with 24 % seizure free patients. The survival rate after 6 months was 72 %. Withdrawal was predominantly related to inefficacy.
On TPM there were 55 % responder with 20 % seizure free patients. The survival rate after 6 months was 65 %, after 12 months 45%. Withdrawal of the drug was more related to inefficacy than side effects. There was a good inverse correlation between level of efficacy and rate of side effects.
On OXC there were 52,9 % responder, with 9,8 % seizure free patients. Survival rate after 6 months was 90 %, after 12 months 79 %. Withdrawal was predominantly related to inefficacy.
CONCLUSIONS: Our figures indicate, that survival rates are not simply related to efficacy and tolerability. The drug (OXC) with the lowest rate of seizure free patients had the highest survival rate, although tolerability is not different. That indicates, that further factors determine the survival rates. One factor e.g. could be the general drug policy and the definition of a first line drug.
These aspects have to be taken into account when survival rates are comparatively studied in clinical settings.