Infographic: Which Rare Diseases Are The Most Common?

Pharmaceuticals have come a long way since the apothecary days of prescribing cocaine drops for toothaches, or dispensing tapeworm diet pills.

Today, medical breakthroughs like antibiotics and vaccines save millions of lives, and contribute to the industry’s mammoth size. Yet even with rapid advancements, a select group of rare diseases still fly under the radar — and together, they affect over 350 million people worldwide.

What Are Rare Diseases?

Today’s infographic from Raconteur breaks down occurrence rates of notable rare diseases, and their collective impact on pharmaceutical drug sales. But first, let’s look at how they’re defined.

Diseases are considered rare, or “orphan” if they affect only a small proportion of the population. In general, it’s estimated that 1 in 17 people will be afflicted by a rare disease in their lifetime. At the same time, as many as 7,000 rare diseases exist, with more discovered every year.

A report by the global investment bank Torreya looks at the most common types of rare diseases that are a focus for therapeutic companies around the world:

  • Multiple sclerosis emerges above all others, at 90 patients per 100,000 people.
  • Narcolepsy—intermittent, uncontrollable episodes of sleepiness—affects 50 patients per 100,000.
  • Primary biliary cholangitis, the damage of bile ducts in the liver, affects 40 people in 100,000.
  • Rounding out the top five orphan diseases are Fabry disease (30 patients per 100,000), and cystic fibrosis (25 patients per 100,000).

One catch behind these stats? There’s actually no universal definition of what constitutes a rare disease. This means prevalence data like the above is often inconsistent, making it difficult to record the precise rate of natural occurrence.

The Cost of Rare Diseases

This gap in knowledge comes at a price—many rare diseases have constrained options for treatment. Orphan drugs are often commercially underdeveloped, as their limited end-market usage means they aren’t usually profitable enough for traditional research.

In the United States, government-backed incentives such as tax credits for R&D costs and clinical trials are speeding up the pathways from drug to market. Other places like the EU, Japan, and Australia are also following suit.

In total, it’s estimated that pharma companies focused on rare diseases are worth about half a trillion in enterprise value, roughly equal to 17.5% of the value of Big Pharma:

  • Non-oncology value: $315.7B
  • Oncology value: $193.1B
  • Total enterprise value: $508.8B

Source: Torreya Report. Market values are for the top 31 pure play rare disease therapeutic companies.

The average cost of an orphan drug per U.S. patient annually can climb to near $151,000 (a whopping 4.5 times that of a non-orphan drug, at $34,000). That’s why the pharma industry is urgently advancing rare disease therapeutics across different categories.

Dominant Orphan Drug Sales

According to other estimates, orphan drugs are set to capture over one-fifth of global prescription sales by 2024. Blood, central nervous system, and respiratory-related drugs are currently the top therapeutic categories and are expected to keep this status into the future.

The figures below break down global orphan drug sales by therapy category, and their present and estimated future market share. Note that oncology-related orphan drug sales are excluded from this table.

Therapy Category 2018 Sales Market Share 2024E Sales Market Share Change in Market Share
Total Sales $67.9B $118.5B
Blood $21.3B 31.4% $33.1B 27.9% -3.4%
Central nervous system (CNS) $11.1B 16.3% $20.3B 17.1% 0.8%
Respiratory $7.8B 11.5% $13.6B 11.5% 0%
Immunomodulators $7B 10.3% $12.5B 10.5% 0.2%
Cardiovascular $6.7B 9.9% $8.5B 7.2% -2.7%
Endocrine $3.8B 5.6% $5.6B 4.7% -0.9%
Musculoskeletal $3.5B 5.2% $11B 9.3% 4.1%
Systemic anti-infectives $3.1B 4.6% $4.2B 3.5% -1%
Gastro-intestinal $2.9B 4.3% $6B 5.1% 0.8%
Genito-urinary $0.6B 0.9% $1.5B 1.3% 0.4%
Sensory organs $0.1B 0.1% $1.5B 1.3% 1.1%
Dermatology $0B 0% $0.7B 0.6% 0.6%

Source: EvaluatePharma. Industry sales are based on the top 500 pharma and biotech companies.

Much is still unknown about rare diseases in the health community. Frequent misdiagnosis, and up to an average of 8 years for an accurate diagnosis, continue to be a problem for patients.

There are two sides to the situation. On one, tech giants like Microsoft are providing digital health solutions to speed up diagnosis, through machine learning and blockchain-based patient registry.

On the other, many skeptics question whether the industry is interested in finding cures for rare diseases at all, especially when they account for a significant portion of industry revenues.

Is curing patients a sustainable business model?

Goldman Sachs