One Rare Disease Biotech Posts 97% Margins but the Faster Growing Rival Just Turned Its First Profit

Corcept Therapeutics (NASDAQ: CORT) and Amicus Therapeutics (NASDAQ: FOLD | FOLD Price Prediction) delivered Q3 2025 results highlighting two rare disease biotechs at opposite ends of the profitability spectrum. Corcept posted revenue of $207.6 million, up 13.7% year-over-year, with net income of $19.4 million. Amicus reported revenue of $169.1 million, up 19.5%, while turning a quarterly profit of $17.3 million after years of losses.

Corcept Slows Down. Amicus Speeds Up.

Corcept built its business on Korlym, a cortisol modulation therapy for Cushing’s syndrome and related metabolic disorders. The product delivers gross margins of 97.8%, but the company burns cash on SG&A ($124 million) and R&D ($69 million) to support pipeline expansion. Operating margin sits at 4.9%, and annual earnings growth collapsed 61% year-over-year despite the revenue bump. The company trades at 42.6x trailing earnings, stretched given the growth deceleration.

Amicus relies on enzyme replacement therapies for lysosomal storage disorders, a narrower but faster-growing market. Its operating margin of 20.3% dwarfs Corcept’s, even though gross margins are lower at 87.4%. The company carries $392 million in long-term debt but just crossed into profitability after 18 consecutive years of losses. Revenue growth of 19.5% outpaces Corcept’s, and the company beat Q3 estimates by 100% ($0.06 actual versus $0.03 expected).

One Defends Turf. One Chases Expansion.

Corcept’s strategy centers on protecting Korlym’s dominant position while advancing its cortisol modulation platform into oncology and psychiatry. The company holds $399 million in investments and $125 million in cash, giving it flexibility to fund trials without tapping debt markets. But insider activity tells a cautious story. CEO Joseph Belanoff exercised 550,000 options at $3.88 on December 24, then immediately sold 306,846 shares at $83.59 the same day. Chief Development Officer William Guyer executed three separate exercise-and-sell cycles since November, acquiring at $21.65 and selling at $74 to $83. This pattern suggests executives are locking in gains, not betting on near-term upside.

Amicus focuses on expanding its enzyme therapy portfolio and improving supply chain efficiency. The company carries $178 million in inventory versus Corcept’s $12 million, reflecting a more complex manufacturing footprint. Management sold heavily into strength in early January, with four C-suite executives disposing of 153,278 shares at $14.27 after the stock recovered from $5.13 lows in November. That 178% recovery created an exit opportunity, and leadership took it.

Which Fits Your Portfolio Better?

If you want a proven, cash-generating business with minimal debt, Corcept fits that profile. But the 42.6x P/E and slowing earnings growth make it expensive. Analysts see upside to $91, but insider selling at $80-plus suggests management thinks the current price is fair.

Amicus offers a turnaround story with faster revenue growth and improving margins. The debt load is manageable if profitability holds, and the valuation is more reasonable given the growth trajectory. I would lean toward Amicus if you believe the profitability inflection is sustainable. Corcept makes more sense if you prioritize balance sheet strength and are willing to pay a premium for stability.