Teva UK has launched generic versions of AstraZeneca’s blockbuster antipsychotic Seroquel and the extended-release Seroquel XR on the first day of patent expiry.

The launch follows the decision by a UK court that the patent on Seroquel XR, extending the brand’s exclusivity, is not valid.

The new generic Quetiapine and Quetiapine (Sondate) XL were also launched on the day that AZ lost its appeal against the FDA’s decision to allow generic competition to Seroquel in the US.

Quetiapine is indicated for treatment of schizophrenia and moderate to severe manic episodes, while Quetiapine XL is indicated for treatment of schizophrenia and bipolar disorder and for adjuvant treatment of major depressive disorder in patients whose response to antidepressant monotherapy is sub-optimal.

Both generics are available on Teva’s PriceWatch service, which matches the lower of Teva’s list price and the month’s average market price.

Kim Innes, Teva UK’s Commercial Director, said: “With the launch of Quetiapine and Quetiapine XL, we’re making more medicines accessible for more people. Launches like these help towards saving the NHS over GBP9bn on generic prescriptions.”

The Seroquel brand accounted for 17% of AstraZeneca’s revenue in 2011, with sales of $5.7bn including Seroquel XR sales of $1.49bn. The Seroquel patent cliff in Europe and the US is expected to impact severely on AZ in 2012.

Teva UK is part of Israel-based Teva Pharmaceutical Industries, the world’s largest generic drug manufacturer.

The SSRI fluoxetine, originally marketed as Prozac, has been shown by a broad analysis of clinical trial data to have no link to increased suicide risk in children and teenagers.

The study allays the concerns that led the FDA to issue a ‘black box warning’ on the drug in 2004, and led many clinicians to question the EMA’s approval of the drug for treatment of children and teenagers in the same year.

An analysis of data from 41 trials with more than 9,000 patients showed that the antidepressants fluoxetine and venlafaxine neither increased nor decreased suicidal thoughts and behaviours in children.

Lead trial author Robert Gibbons, Professor of Medicine, Health Studies and Psychiatry at the University of Chicago Medicine, said the new findings should reassure doctors about the safety of prescribing these medications.

The FDA’s black box warning on fluoxetine was prompted by retrospective adverse event data from 25 clinical trials (based primarily on self-reporting), which revealed a small but significant increase in suicidal thoughts and behaviour in patients aged below 25.

The new analysis was based largely on a major National Institute of Mental Health study of fluoxetine and venlafaxine, including weekly screening of patients for depression and suicidal thoughts, and comparing the effects of drug and placebo.

Trials of fluoxetine in children showed a reduction in depressive symptoms relative to placebo, but no significant change in suicide risk.

Gibbons commented that the lack of a direct impact on suicidal thoughts suggests that “the effects of antidepressants in kids and adults are not really the same, since we don’t see anything but beneficial effects of antidepressants in adults. In kids, we don’t see a harmful effect, but we do see a disassociation between the beneficial effects on depression and the potential beneficial effect on suicide.”

Previous FDA research found that the ‘black box warning’ on fluoxetine had significantly reduced antidepressant prescriptions to both children and adults, and this correlated with an increase in suicide rates.

AstraZenca’s Seroquel XR (quetiapine fumarate) has been given a positive decision by the European Commission (EC).

Following a recommendation by the Committee for Medicinal Products for Human Use (CHMP) in April, the extended release tablets can now be given to patients with major depressive disorder (MDD) who have not responded to antidepressant monotherapy.

AstraZeneca must now obtain local approvals over the next month in the 17 member states that took part in the mutual recognition procedure.

The decision from the EC follows a similar recommendation from the FDA in the US.

Seroquel is AZ’s second-biggest selling drug despite being involved in US lawsuits including thousands of plaintiffs. Last month AstraZeneca announced it was to pay £198 million to settle two-thirds of cases after claims Seroquel caused diabetes in a number of patients.

Weight gain is one of the areas of product information to be updated within the EU application, along with suicidality, hyperglycaemia, somnolence, orthostatic hypotension, and dizziness.

The drug has already been approved in a number of countries for schizophrenia, bipolar mania, bipolar depression, MDD and generalised anxiety disorder.