Johnson & Johnson (JNJ +0.65%) faces stiff competition in the battle for prostate cancer market share. The company's Zytiga is enjoying rapid sales growth in second- and third-line treatment as people live longer and the number of cases diagnosed and treatments prescribed climbs. Zytiga's market growth has caught the attention of big pharmaceutical companies and a slate of young up-and-comers.
Approvals have pushed Zytiga higher
J&J landed approval from the Food and Drug Administration for Zytiga as a treatment for metastatic castration-resistant prostate cancer, or mCRPC, in April 2011. The approval gave Zytiga, which is dosed orally, pole position in prescriptions for patients who had previously been treated -- and failed -- with intravenous docetaxol. The approval stemmed from positive phase 3 trial data, which showed that patients treated with Zytiga had overall survival of 15.8 months versus 11.2 months for patients treated with placebo.
In December, Zytiga got another boost when the FDA approved the drug as a treatment that could be used before chemotherapy. That decision essentially elevated Zytiga into a sure-footed second-line treatment. In a trial of patients who had not been treated with chemotherapy, overall survival was 35.3 months versus 30.1 months on placebo. While overall survival didn't meet statistical significance, Zytiga did significantly improve the amount of time patients were able to postpone taking opiates for pain and for having to initiate chemotherapy. In follow-up data released by J&J in February, those patients saw a 47% statistically significant improvement in disease progression, with median radiographic progression-free survival of 16.5 months versus 8.3 months for the control arm.
As a result of the additional approval in December, Zytiga U.S. sales jumped to $192 million in the second quarter, making it one of the top 100 drugs sold in the U.S. last quarter. Worldwide, Zytiga notched sales of $395 million, up 70% from last year. Those sales put the drug on pace for $1.6 billion in global sales, nicely above impressive first-year sales of $961 million in 2012.
Sales suggest that industry watchers' forecasts may be too conservative. One firm, Decision Resources, estimated that Zytiga sales would hit $1.8 billion in 2015. That prediction came last fall, prior to the new indication, and now seems a bit tepid.
Big markets mean big competition
One of J&J's biggest challengers is Medivation (MDVN +0.00%) and Astellas' co-marketed drug Xtandi.
Xtandi has already grabbed 50% of the third-line treatment market for prostate cancer and 20% of the market for second line treatment. If results from trials studying Xtandi in pre-chemo patients are strong when announced later this year, Xtandi could gain additional ground on Zytiga.
Exelixis' (EXEL +2.44%) lead drug, Cometriq, garnered attention with data presented at ASCO earlier this year showing that mCRPC patients, 73% of which had undergone two or more prior treatments, had median overall survival of 10.8 months. In earlier trials, the company reported that Cometriq had cleared bone masses in 19 of 20 prostate cancer patients. Exelixis is currently studying Cometriq in phase 3 trials to evaluate the drug versus prednisone and mitoxantrone plus prednisone. Exelixis is expected to release phase 3 data next year.
Bristol-Myers Squibb (BMY +0.22%) also hopes to win prostate cancer prescriptions with its cancer drug Yervoy. That drug is already approved as a treatment for metastatic melanoma and produced $706 million in sales for Bristol-Myers last year. However, phase 3 results released in September showed that the drug missed its endpoint for overall survival in prostate cancer. While disappointing on overall survival, Yervoy did see statistically significant results for progression-free survival. As a result, Bristol-Myers thinks immunotherapy drugs like Yervoy may be able to carve out some share of the prostate cancer market.
"We are committed to continuing our development of Yervoy in prostate cancer," said Bristol Myers Senior Vice President of Global Development and Medical Affairs Brian Daniels when the data was released. The company has another phase 3 study ongoing for earlier stage prostate cancer patients, which it hopes to have data released from in 2015.
Another potential competitor is OncoGenex Pharmaceuticals. OncoGenex has an ongoing phase 3 study evaluating custirsen, used with docetaxol, in mCRPC. Data from this trial is expected in the first half of next year. The company hopes phase 3 will mirror phase 2 results, which showed that patients treated with the combination saw median overall survival of 23.8 months, versus 16.9 months for docetaxol alone.
OncoGenex is also studying curstirsen alongside Sanofi's (SNY +0.28%) Jevtana. Jevtana gained approval in 2010, giving Sanofi the chance to maintain some market share when its branded docetaxol, sold as Taxotere, went off patent. In clinic, Sanofi evaluated Jevtana in advanced prostate cancer patients who had failed on docetaxol, showing median overall survival improved to 15.1 months versus 12.7 months for generic mitoxantrone -- a competing treatment option. Unfortunately for Sanofi, Jevtana hasn't lived up to expectations, with first-half sales slipping 10% to $106 million, as prescriptions moved to Zytiga and Xtandi. Finally, OncoGenex also has a phase 2 trial of custirsen used alongside Zytiga.
The final Foolish take
J&J's Zytiga is off to a fast start, racking up blockbuster status in just its second year on the market. But Xtandi presents the biggest near-term threat. In an attempt to trump Xtandi, J&J made an interesting move this summer, acquiring little-known Aragon Pharmaceuticals and its lead product, ARN-509. ARN-509 was developed in the same labs as Xtandi, and in phase 1 trials nearly 47% of ARN-509 patients saw their PSA drop by at least 50% over 12 weeks. Interim phase 2 data shows that at least one cohort had a 91% response rate after 12 weeks. That acquisition gives J&J multiple options. It can develop ARN-509 as a successor to Zytiga, or as a combination therapy with Zytiga given they have different mechanisms of action. Importantly, ARN-509 may provide a stronger alternative to Medivation's Xtandi. Of course, all that assumes that ARN-509 remains successful in clinic.
