NEW YORK, NY / ACCESSWIRE / December 1, 2014 / With the recent bankruptcy of Dendreon Corporation (NASDAQ:DNDN) due to disappointing sales of its flagship Provenge prostate cancer vaccine, the future of cancer immunotherapy just got a bit cloudier. While Provenge itself will survive, Dendreon may end up going private in a debt restructuring deal.

But while it may look grim now, the fact remains that sales of Provenge will reach the $300M mark this year, a nice sum for any company from startup biotech to Big Pharma. It just wasn't enough to overcome the debt incurred to develop it. Clearly then, there is a significant market for cancer vaccines. The trick is to develop the treatments at much cheaper cost.

Vaccines though, are only one approach of two when it comes to cancer immunotherapy. In a vaccine like Provenge, the goal is to stimulate the immune system to build indigenous antibodies against a given illness be it a tumor or a virus. The second approach is to engineer the antibodies themselves and use them directly as the treatment.

This second approach is known as monoclonal antibodies or mAbs, where the immune molecules are usually engineered using antigens and then humanized and cloned. The advantage over a vaccine is that monoclonal antibodies are generally more targeted than vaccines, since the effectiveness of a vaccine depends on effective antibodies being produced by the patient in response to it, while the antibodies themselves are already engineered to be effective on a specific disease. The disadvantages are that unlike vaccines used to train a patient's own immune system, sometimes engineered and then humanized monoclonal antibodies can trigger extreme side effects by causing an immune overreaction.

Be that as it may, the whole monoclonal antibody market is huge. Already 8 years ago it passed the $20B mark, and is expected to pass $140B in just three years. While Provenge is and remains the only FDA approved cancer vaccine, 17 monoclonal antibody treatments have been approved as cancer treatments since 2000.

Provenge?s cost is a prohibitive $93,000 per treatment regimen, a big factor in its inability to sell enough to keep Dendreon afloat. The cost of mAb cancer treatments are usually lower, in some instances only a fraction of that cost. Last year's bestselling mAb cancer immunotherapy, Roche's (OTCMKTS:RHHBY) Rituxan for lymphoma, costs between $18,000 and $27,000 a year depending on the number of treatments required. It sold $7.5B last year. Herceptin for breast cancer costs $70,000 a year or 25% less than Provenge, and sold $6.5B last year. Roche's other bestselling cancer mAb, Avastin, costs anywhere from $40,000 to $100,000 a year depending on the disease and where the patient is being treated. Avastin also clocked in at $6.5B last year.

Continuing down the list of blockbusters, Bristol Myers Squibb's (NYSE:BMY) and Eli Lilly's (NYSE:LLY) Erbitux for colon and lung cancer costs up to $80,000 a year and sold $3B in 2013. $80,000 is very high, but still less than Provenge. Amgen's (NASDAQ:AMGN) Prolia for prostate, breast, and bone cancer is dirt cheap by comparison at $1,650 a month, or less than $20,000 annually. It sold $1.5B in 2013. The final oncology mAb to make the blockbuster cut at $1B in sales is Bristol's Yervoy for melanoma, which costs an astronomical $120,000 per treatment.

What these numbers mainly show is that the cost of monoclonal antibody cancer immunotherapy treatments vary wildly, and often unpredictably. What they also show is that they have the potential to reach blockbuster proportions seemingly regardless of the cost. The market seems predisposed to mAbs over Provenge-like vaccines. They have been on the market for much longer, apply to many more diseases besides just cancer, there is more than only one of them on the market, and physicians are more familiar with them as a treatment option.

Still, the advantages of cancer vaccines cannot simply be disregarded. Mainly, training the immune system to attack cancer is much safer in terms of side effects than introducing a foreign humanized antibody that sometimes carry with them major systemic adverse reactions. One company though is now at the beginning stages of developing a mAb treatment that itself derives from cancer vaccines in an adjuvant setting, perhaps setting up a best-of-both-worlds scenario in a two-pronged approach to cancer immunotherapy.

MabVax Therapeutics (OTCMKTS:MBVX), a newly public biotech, is tackling this double approach by teaming up with Memorial Sloan Kettering Cancer Center. MabVax has exclusive access to the antibodies produced by cancer patients at the Center who are responding to 8 different vaccines owned by Sloan Kettering. MabVax takes these samples taken at the peak of response to the vaccines and finds the best antibody produced from them, and then clones that antibody.

Its lead mAb candidate is called HuMab 5B1, which has shown specificity towards pancreatic cancer, and is now being investigated in dual phase 1 trials as a therapeutic as well as an imaging agent for that disease. The advantages of discovering mAbs in this way are that they are fully human rather than humanized after being engineered, and therefore are less likely to cause serious systemic side effects in immune overreactions. At the same time, there is still the advantage of the specificity of mAbs over luck-of-the-draw vaccine antibodies in this case. HuMab 5B1, in this case, was specifically picked as the most effective human antibody produced in response to a vaccine.

Conclusion

Despite Dendreon's failure, blockbuster potential is still there for Provenge for whoever ends up purchasing the rights to it. And while mAbs certainly have their advantages over cancer vaccines such as Provenge, both approaches to cancer immunotherapy have their ups and downs. What may be needed as a next step in cancer immunotherapy is an approach such as MabVax's that combines the advantages of mAbs with those of cancer vaccines.

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SOURCE: Market Exclusive