Medivation roars back to life as prostate cancer drug delivers

After the big disappointment that was Dimebon, Medivation needed a win and MDV3100 has delivered. Shares in the California group doubled to a 20-month high of $35 on news that the prostate cancer treatment’s first pivotal trial had ended early because of a clear survival benefit.

Given that its survival benefit equalled or exceeded marketed products and late stage candidates, and did so as a single agent, observers reckon MDV3100 should match up well against competitors in the post-chemotherapy setting, including Johnson & Johnson’s Zytiga. With additional data coming in patients naïve to chemotherapy, expectations are high that Medivation’s compound could achieve much wider use in castrate-resistant prostate cancer patients.

Competitive numbers

At an interim analysis triggered by the 520th death, the 1,199-patient trial of MDV3100 found that men taking the oral androgen receptor signalling inhibitor had a median survival 4.8 months longer than those taking placebo, 18.4 versus 13.6 months. The extended survival numbers are similar to those of Zytiga, which reported a 3.9 month benefit in its primary analysis and 4.6 months in a later analysis that incorporated more deaths from its pivotal trial.

The advantage for MDV3100 is that it was tested as a monotherapy, whilst Zytiga is taken in combination with prednisone. Management of prednisone’s side effects require more intensive patient monitoring; thus the avoidance of the steroid co-administration may make MDV3100 a more attractive compound for urologists.

Medivation reported little beyond the topline overall survival numbers, although the fact that MDV3100 was made available to patients in the placebo arm suggests there were few safety concerns. More data will be disclosed at an upcoming medical conference.

Competitors fall

The knock-on effects in the prostate cancer space were immediate. Analysts from UBS trimmed Zytiga’s 2015 sales forecast by 25%, to $1.5bn. Algeta, which recently reported a 2.8 month survival advantage in post-chemo patients for its radiotherapy Alpharadin, fell 2% to NKr186 (Alpharadin data should win friends and influence, September 27 2011).

Shares in Dendreon, whose immunotherapy Provenge would be directly challenged in the pre-chemo population should MDV3100 succeed there, dropped 35% to $6.76 in early trade; that the Washington group reported disappointing third quarter sales post market on Wednesday no doubt helped to depress its shares.

As Dimebon’s failures in both Alzheimer’s and Parkinson’s diseases have led to serious raps to its shares this year and last, success with MDV3100 comes as welcome relief to Medivation, as it can now look ahead to regulatory filing in 2012 (Event - Medivation nearing make-or-break read out on prostate cancer drug, August 12, 2011).

Medivation shares US co-promotion rights with worldwide marketing partner Astellas Pharma. EvaluatePharmaconsensus forecasts show partnership revenue of $366m for Medivation in 2016.

Those revenue forecasts give MDV3100 a net present value of $1.2bn for Medivation, equal to its market capitalisation based on intraday share prices. Given the growing optimism for the pill, however, it would not be surprising to see equity analysts raising their forecasts in the near future.

Medivation has roared back to life with the MDV3100 results, with its share price nearly matching lofty pre-Dimebon values. The company and its Japanese partner now need to execute a successful regulatory strategy, as well as hope for a second positive trial and no safety signals, for those values to be sustained.

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