3 New Breast Cancer Treatments Worth Watching

Breast cancer, the most common cancer among women, is still a leading cause of death despite major advances in therapies over the past 15 years.

But the market for breast-cancer treatments traditionally dominated by Roche could soon be challenged by three new contenders -- Novartis , Pfizer , and Eli Lilly .

Here come the new challengers
Novartis, Pfizer, and Eli Lilly are racing against each other to launch a new class of breast-cancer treatments known as CDK (cyclin dependent kinase) inhibitors. CDKs are enzymes that regulate cell division, but when they become overactive or cease to function, cells can proliferate wildly. All three companies are targeting two specific types of CDK -- 4 and 6 -- in order to shut down retinoblastoma phosphorylation, which causes unregulated cell division and tumor growth.

Traditionally, breast-cancer patients have five common options -- surgery, hormone therapy, radiation therapy, chemotherapy, and targeted drugs. Roche has dominated the targeted drugs market with three main treatments (Herceptin, Kadcyla, Perjeta) for HER2 (human epidermal growth receptor 2) positive breast cancer -- a particularly aggressive cancer that accounts for 15% to 25% of breast-cancer cases.

The growth potential of CDK treatments
Let's compare the three new CDK breast cancer treatments that Novartis, Pfizer, and Eli Lilly are working on.



Main Indications




HER2 negative, ER positive breast cancer

In phase 3



HER2 negative, ER positive breast cancer, melanoma

Entering phase 3

Eli Lilly


breast, lung, colorectal, brain, and blood cancers

In phase 1

Sources: Company and industry websites.

Analysts believe Pfizer's palbociclib could generate peak sales of $1.9 billion by 2019, and up to $5 billion annually if approved for other indications. In April, the FDA granted palbociclib a breakthrough therapy designation, putting it on the fast track to an eventual approval by 2015.

Palbociclib is being tested with letrozole against a group that is receiving letrozole alone. Letrozole is a breast cancer drug for postmenopausal women originally manufactured by Novartis as Femara, but is now widely available in generic form.

Novartis only recently announced that LEE011 was entering phase 3 trials for breast cancer, completely surprising Pfizer and analysts, who had not factored in the possible approval of a new breast-cancer drug into forward-sales projections. Novartis' phase 3 trial will also test LEE011 with letrozole against letrozole alone. The trial, which consists of 500 women, is expected to complete by November 2016.

Meanwhile, Lilly still trails far behind both Pfizer and Novartis, and is still testing the drug on a much wider variety of indications.

Targeting a larger market
Both Novartis and Pfizer are attempting to treat HER2 negative and ER (estrogen receptor) positive breast cancer. This means that both targeted treatments are aiming at a much larger potential market than Roche's treatments, since HER2 negative and ER positive breast cancers both account for over 75% of all breast-cancer cases.

Whereas Roche's treatments generally target the overexpression of HER2 by blocking the cancer cells' growth receptors and marking them for the immune system to "see," these newer CDK inhibitors target enzymes, which could treat other cancers in addition to breast cancer.

Roche's Avastin was originally used as a wider reaching treatment for women with late-stage breast cancer, but the FDA revoked that indication in November 2011 due to questionable efficacy and potentially serious side effects.

What CDK inhibitors could mean for Pfizer, Novartis, and Eli Lilly
Going forward, these new treatments represent strong growth opportunities for Pfizer, Novartis, and Eli Lilly, which have all struggled with patent expirations of blockbuster drugs.

Pfizer's problems are perhaps the best known -- sales of its blockbuster cholesterol drug Lipitor, once the best-selling drug in the world, have plunged since its patent expiration in 2011. To fill the void left by the drug, which generated peak sales of $13 billion in 2011, Pfizer has looked toward growing its oncology portfolio.

Pfizer's oncology portfolio is tiny, only accounting for 3% of its total sales last quarter, but it is also the fastest growing segment, posting 24% year-over-year growth. Pfizer's two fastest-growing cancer treatments are Xalkori, a treatment for non-small-cell-lung cancer, and Inlyta, a late-stage kidney-cancer treatment. Sales of Xalkori and Inlyta respectively climbed 93% and 186% last quarter, but together they only generated $156 million in sales. Therefore, adding palbociclib to its oncology portfolio could seriously increase its oncology's portfolio weight and growth potential.

Meanwhile, Novartis investors have been worried about the patent expiry of the blood pressure treatment Diovan, its second top-selling drug, which generated $4.4 billion in 2012 sales. Diovan's patent expired last year, but no generic competitors have emerged yet. Novartis also must deal with the upcoming patent expiration of Glivec, its best-selling blood-cancer treatment that generated $4.7 billion in sales last year. A new breast-cancer treatment could assist its MS treatment Gilenya and respiratory portfolio in offsetting future losses.

For Eli Lilly, the benefits are clear -- it has failed to produce any viable replacements for Cymbalta, its expiring blockbuster antidepressant that generated $5 billion in revenue last year. To make matters worse, it reported two major failures in Alzheimer's treatments, which cast serious doubts on the future direction of the company. But Lilly's CDK inhibitor lags too far behind Pfizer and Novartis' treatments to make a noticeable impact.

The Foolish bottom line
In closing, investors should pay close attention to how the CDK competition between Pfizer, Novartis, and Eli Lilly plays out, since it could unlock a promising new method of treating various types of cancer. These treatments could also represent new opportunities for Pfizer and Novartis to boost their oncology portfolios to finally challenge Roche, the 800-pound gorilla in the field.

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The article 3 New Breast Cancer Treatments Worth Watching originally appeared on Fool.com.

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