Caprelsa: AstraZeneca plc (ADR) (NYSE:AZN)‘s Caprelsa was approved to treat unresectable, locally advanced, or metastatic medullary thyroid cancer in April 2011. In trials, AstraZeneca plc (ADR) (NYSE:AZN)’s pill increased progression-free survival over the placebo and delivered an overall response rate of 44%, compared with just 1% for the placebo — although it should be noted that all responses were partial. However, Caprelsa also comes with a laundry list of side effects that range from something as simple as rash, nausea, and hypertension, to having resulted in death from respiratory arrest and cardiac failure with arrhythmia.
Cometriq: Exelixis, Inc. (NASDAQ:EXEL)‘s Cometriq was approved last November to treat progressive metastatic medullary thyroid cancer. The capsules work by inhibiting multiple tyrosine kinases, which are crucial to blood vessel growth in solid and metastasizing tumors. In late-stage trials, patients receiving Cometriq demonstrated an astounding 11.2 months of progression-free survival compared with just four months for the placebo. Further, the objective response rate was 27% in the Cometriq arm and a goose egg for the placebo arm. Similar to AstraZeneca plc (ADR) (NYSE:AZN)’s Caprelsa, severe adverse reactions tended to increase for Cometriq users relative to the placebo.
Just as we’ve witnessed with every previous cancer in this series, not every drug trial proves successful. Pfizer Inc. (NYSE:PFE)‘s Sutent, for instance, is a very successful treatment for kidney cancer, gastrointestinal stromal tumors, and pancreatic endocrine tumors, but it didn’t fare as well when it came to thyroid cancer. In a midstage trial targeting locally advanced or metastatic anaplastic differentiated thyroid cancer, Sutent was linked to two serious cardiac side effects that an independent monitoring committee felt required a close follow-up. This may not preclude Sutent from an eventual approval in helping advanced cases of thyroid cancer, but its side effects were enough to curb most of the enthusiasm investors had for the adding another indication.
What’s coming down the pipeline
With surgery and/or radioactive iodine therapy being such an effective tool in treating the majority of thyroid cancer cases, outside of early stage trials and preclinical studies there isn’t much going on in the thyroid cancer pipeline. There is one late-stage treatment in development that could provide a better outlook for those suffering with a more aggressive form of the disease: Nexavar.
Bayer and Onyx Pharmaceuticals, Inc. (NASDAQ:ONXX)‘s anti-cancer agent Nexavar could be well on its way to receiving FDA approval for patients with locally advanced or metastatic radioactive iodine-refractory differentiated thyroid cancer. Announced in early January, results from the late-stage trial demonstrated improved progression-free survival relative to the placebo. Nexavar, which is given in a tablet form twice daily, works by blocking receptors responsible for blood vessel growth, thereby starving the tumor, or tumors, of nutrients and oxygen needed to grow.
Your best investment
The good news with thyroid cancer is that a diagnosis isn’t a death sentence and that it’s curable if caught early enough. On the other hand, thyroid cancer also isn’t an area of intense research, since surgery and radioactive iodine treatments seem to cure a vast majority of the population, even if thyroid cases are on the rise.
Normally I would break this section into a riskier and safer investment option, but in this case I think both Exelixis, Inc. (NASDAQ:EXEL) and Onyx Pharmaceuticals, Inc. (NASDAQ:ONXX) represent one and the same. Nexavar is already approved to treat unresectable hepatocellular carcinoma and renal cell carcinoma and looks poised to gain the indication to treat an advanced form of thyroid cancer as well.
Likewise, Exelixis, Inc. (NASDAQ:EXEL) is the pure play on metastatic medullary thyroid cancer. The fact that Cometriq nearly tripled PFS in trials compared to the placebo makes it the clear choice over AstraZeneca plc (ADR) (NYSE:AZN)’s Caprelsa, and its efficacy in bone metastases in trials has thus far been very impressive. Exelixis, Inc. (NASDAQ:EXEL) will need additional indications for Cometriq to become profitable, but it appears to have the highest risk-versus-reward ratio here, depending on Cometriq’s success moving forward.
Stay tuned next week, when we tackle the current and upcoming therapies for the treatment of kidney cancer in this “Tackling Cancer” series.
The article Tackling Cancer: Thyroid Cancer’s Biggest Current and Upcoming Players originally appeared on Fool.com.
Fool contributor Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.The Motley Fool owns shares of, and recommends, Exelixis.
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