Image source: National Cancer Institute.

Cancer is an utterly terrifying six-letter word since it's a disease that's still largely a mystery to researchers, and in many cases, there are no definitive cures. Chances are better than not that you, or someone close to you, has battled cancer, with men and women having a respective 42% and 38% chance of developing cancer during their lifetimes.

However, some types of cancer are considerably scarier than others. Although everything depends on the stage at which cancer is diagnosed, men with prostate cancer have about a 99% chance of surviving for at least five years post-diagnosis according to the 2016 Cancer Facts and Figures report from the American Cancer Society. In this respect, a cancer diagnosis, while scary, is far from a death sentence.

On the other end of the spectrum are diseases like pancreatic cancer and lung/bronchus cancer, which have much lower five-year survival rates. Per ACS data, pancreatic cancer has just an 8% five-year survival rate, with a five-year survival rate of just 18% for lung and bronchus cancer. The latter disease is a particular worry since lung cancer is the leading cancer-related cause of death in the United States. ACS estimated that more than 158,000 people would die of lung cancer in 2016 compared to the next-deadliest cancer type, colorectal cancer, with around 49,200 estimated deaths this year.

A number of new lung cancer drugs have recently hit pharmacy shelves

Still, researchers aren't sitting idly by and letting cancer proliferate at will. If you haven't been paying close attention to the latest drug breakthroughs, you'd have missed not one, two, or three... but five new lung cancer drug approvals since October.

These new therapies generally fall into one of two categories: immunotherapy or gene-specific.

Opdivo & Keytruda

Unquestionably the biggest step forward in lung cancer treatment came in the form of a label expansion for Bristol-Myers Squibb's (BMY -1.89%) Opdivo and Merck's (MRK -0.01%) Keytruda.

Image source: Bristol-Myers Squibb.

Opdivo and Keytruda are both cancer immunotherapies, a new type of drug designed to expose cancer cells to the immune system to allow it to attack. Opdivo and Keytruda work to inhibit PD-1, a checkpoint protein found on a type of immune system cell known as a T-cell. By binding with PD-1, it disallows the interaction of PD-1 with PD-L1 receptors on the outside of cancer cells, cutting off cancer's ability to hide from the immune system.

Currently, Opdivo is approved to treat second-line metastatic non-small cell lung cancer (NSCLC) for both squamous and non-squamous NSCLC (Opdivo received FDA approval for squamous NSCLC in March 2015 and the larger non-squamous indication in Oct. 2015). Merck's Keytruda is approved to treat second-line metastatic NSCLC in instances where patients have high levels of PD-L1 expression from their tumors. It, too, received FDA approval for this indication in October.

Opdivo's approval came after overall survival improved to an average of 12.2 months compared to the docetaxel arm, where median survival was 9.4 months. Additionally, 19% of patients treated with Opdivo exhibited a complete or partial response, with those experiencing a response having a median duration of 17 months. Comparatively, the docetaxel arm has a 12% complete or partial tumor shrinkage rate, with an average duration of just six months. Bristol-Myers is currently running dozens of additional combination studies with Opdivo with the possibility that peak annual sales could eventually top $10 billion. 

Image source: Merck.

Merck's Keytruda had its label expanded after it met its primary endpoint of a superior overall response rate relative to the placebo. In the subgroup of patients tested, Keytruda generated a 41% overall response rate with an average duration lasting between 2.1 months and 9.1 months. Mind you, typical response rates for NSCLC could be anywhere from 10% to 20%, so Keytruda is a major step forward. Sales of Merck's Keytruda should easily eclipse $1 billion in 2016.

Alecensa & Tagrisso

As researchers learn more about why cancer forms and how it spreads, they've discovered certain genetic mutations along the way believed to lead to the formation of cancer. They've therefore spent the time to develop drugs to target these mutations. Two newly approved gene-based lung cancer therapies are Roche's (RHHBY 0.38%) Alecensa and AstraZeneca's (AZN -0.79%) Tagrisso.

The thing to know about gene-focused medicines is that they're inherently patient-pool-inhibitive. In other words, they're typically focused on only a small percentage of a diseases patient population. On the other hand, focusing on a specific genetic mutation can lead to unparalleled response rates.

For example, Roche's Alecensa is an oral therapy that targets patients with ALK-positive advanced NSCLC. This is a gene mutation found in about 5% of NSCLC patients. But the clinical results from its two studies that led to approval were phenomenal. In the first study, the overall response rate was 38% with an average duration of response of 7.5 months. The second study was even more impressive, with an overall response rate of 44% and an average duration of response of 11.2 months! Additionally, 61% of patients who also had measurable brain metastases experienced a complete or partial reduction in the size of their brain tumors.

Image source: Getty Images. 

AstraZeneca's Tagrisso is another oral advanced NSCLC medication that targets a specific mutation -- in this instance, epidermal growth factor receptor (EGFR) mutation T790M. Tagrisso had some of the most impressive response rates we've seen for a cancer drug. Over two studies, 57% and 61% of T790M mutation-positive patients experienced a complete or partial reduction in their tumor size despite progressing on a prior EGFR-blocking medication.

These gene-focused therapies aren't cheap, but they've given patients with these rare mutations a much better chance of exhibiting a durable response.


Lastly, the FDA also approved Eli Lilly's (LLY 0.69%) Portrazza, a drug used in combination with two other forms of chemotherapy to treat first-line advanced squamous NSCLC patients.

Portrazza is a monoclonal antibody that's targeted at inhibiting EGFR, the aforementioned protein commonly found on squamous NSCLC tumors. In clinical studies, Lilly's Portrazza helped improve median overall survival to 11.5 months in combination with Gemzar and cisplatin as opposed to a median overall survival of 9.9 months that the placebo cisplatin and Gemzar arm produced.

The point is, we are beginning to see meaningful progress in even the toughest-to-treat cancer indications. This progress may not be of the same lightning speed with which we saw an effective hepatitis C cure produced, but it's progress in the right direction that drugmakers can be proud of.