Generic Olanzapine: Health Authority Opportunity or Nightmare?

A. Aleksander Araszkiewicz; Katarzyna Szabert; Brian Godman; Magdalena Wladysiuk; Corrado Barbui; Alan Haycox

Disclosures

Expert Rev Pharmacoeconomics Outcomes Res. 2008;8(6):549-555. 

In This Article

Expert Commentary and Five-year View

We acknowledge that the patient numbers are small. This is because there is no general practitioner (GP) gate keeping system for patients with mental health conditions in Poland (i.e., patients can readily access psychiatrists without a GP referral). However, the follow-up has been extensive, averaging for instance over 4 years in switched patients, approximately 2 years while prescribed Zyprexa and 2 years whilst prescribed generic olanzapine ( Table 2 ). This was greater than the 4-12 months in three published studies analyzing the impact of generic clozapine.[23,24,25] Follow-up was similar or greater in the majority of the switched patients compared with the 2-year study by Healy and colleagues[22] We believe this long follow-up period is necessary given the fact that patients can be dispensed different olanzapine formulations on different visits to the community pharmacy, coupled with previous concerns with generic drugs for patients with schizophrenia.[18,19,20,21]

We also acknowledge that there are obvious flaws with the retrospective study design, especially given the heterogeneous outpatient population, although the 25 switched patients act as a control comparison group. In addition, this is a descriptive study. We further acknowledge there are concerns with analyzing patients' notes retrospectively, especially given the paucity of data to undertake a full economic study. However, the study reflects 'real life' practice where there is significantly less patient monitoring than undertaken in randomized clinical trials, as well as incorporating the community pharmacy and patient dynamics.

Concerns with analyzing patients' notes retrospectively include the dependency for events and outcomes to be accurately recorded. In addition, as previously stated, the branded olanzapine formulation dispensed by community pharmacists may well be different from the formulation recorded in patients' notes. This is similar to other European countries once multiple sources become available adding to health authority and physician interest in these findings. Despite these flaws, we believe that the results from this limited retrospective review suggest similar effective doses as well as similar number of relapses when accounting for length of follow-up for both Zyprexa and the various generic olanzapine formulations (Figure 1). This is because there were a similar number of relapses in the 25 switched patients while prescribed Zyprexa or generic olanzapine, especially when factoring in the longer follow-up period for patients prescribed generic olanzapine ( Table 2 ).

There were no untoward or unexplained relapses in patients prescribed various generic olanzapine formulations. In addition, no outpatient prescribed generic olanzapine requested to be represcribed Zyprexa. This is despite promulgated concerns about the quality of generic olanzapine and possible compliance fears if patients receive a different formulation on successive visits to community pharmacists potentially leading to increased number of relapses. There was no known backlash from either psychiatrists or patients when Zyprexa was temporarily removed from the market on 1 July, 2005. This was no doubt helped by psychiatrists explaining to patients beforehand that they may receive different packages with different color and shaped tablets from community pharmacies with generics becoming available. However, these will have similar efficacy to Zyprexa.

There are considerable cost savings with the availability of multiple generic olanzapine formulations. If similar price reductions were seen, for instance, in England, there are potential savings of over £35.0 million per year based on current sales of olanzapine of over £107 million per year[44] and current international non-proprietary names (INN) prescribing rates of 81.8%.[46] These savings will grow as more branded generic olanzapines are launched in Poland matching the significant reduction seen in the cost/DDD of generic risperidone. These represent marginal costs savings with similar dosing, side effects, outpatient intensity and relapse rates between the olanzapine patient groups. However, this statement must be treated with caution given the lack of resource information in the patients' notes.

Overall, the results from this initial limited study in Poland suggest generic olanzapine may be prescribed with confidence when eventually launched throughout Europe, and is unlikely to be a 'nightmare' situation. When these findings are duplicated, the considerable resources savings can be used to fund new premium priced innovative drugs that help reduce relapse rates in refractory patients as well as greater volumes of atypical antipsychotics in place of typical antipsychotics.

Retrospective reviews are also planned with risperidone now that there are no supply problems in Poland and 14 branded generics are currently available. This is especially because there are concerns with the narrow therapeutic index of risperidone whereby small increases in serum concentrations can lead to additional extra pyramidal symptoms. Alongside this, there are concerns regarding the bioavailability of current generic formulations.[38] However, our impression to date is that there are no obvious clinical and patient problems with generic risperidone in Poland matching the situation with generic olanzapine. This needs to be confirmed before any definitive statements can be made.

Finally, this article endorses the need for psychiatrists to improve the accuracy of their note-taking, such as the rationale behind adverse events, the rationale for relapses and subsequent management, as well as the extent and rationale for discontinuation of any antipsychotic medication. This is a problem generally, and not just in Poland. Addressing this will improve patient care especially when patients see multiple psychiatrists over time within a clinic or Medical Academy situation. Spending additional time with patients discussing potential side effects of atypicals and the need for good adherence, should help address compliance issues in the community. Poor compliance[28] should be a greater concern than bioavailability due to generic atypicals given recent publications with generic clozapine,[22,23,24,25] the findings from this retrospective article, and our impression to date with generic risperidone.

These are debates and challenges for the future as more standard pharmaceuticals lose their patents[39] including drugs to treat mental health diseases.

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