Why This Fund Made a $189 Million Bet on Erasca as Shares Skyrocket 800%

RTW Investments disclosed in a May 15, 2026, SEC filing that it bought 16,010,524 shares of Erasca (NASDAQ:ERAS), an estimated $189.23 million trade based on quarterly average pricing.

What happened

According to a May 15, 2026, SEC filing, RTW Investments increased its holdings in Erasca by 16,010,524 shares during the first quarter of 2026. The estimated transaction value is $189.23 million, calculated using the average closing price for the period. The fund’s quarter-end stake in Erasca was valued at $261.42 million, up $260.88 million from the prior quarter, a figure that incorporates both share purchases and pricing effects.

What else to know

• This was a buy; as of March 31, 2026, Erasca made up 2.6% of RTW Investments’ 13F reportable AUM.
• Top holdings after the filing:
  • NASDAQ:MDGL: $1.04 billion (10.4% of AUM)
  • NASDAQ:INSM: $791.91 million (7.9% of AUM)
  • NASDAQ:PTGX: $533.22 million (5.3% of AUM)
  • NASDAQ:PTCT: $527.76 million (5.3% of AUM)
  • NASDAQ:ARGX: $518.07 million (5.2% of AUM)
• As of Friday, Erasca shares were priced at $12.84, up nearly 800% over the past year and well outperforming the S&P 500, which is up 28%.

Company Overview

Company Snapshot

• Erasca develops oral inhibitors targeting the RAS/MAPK pathway for cancer treatment, with lead candidates including ERAS-007 (ERK1/2 inhibitor), ERAS-601 (SHP2 inhibitor), and ERAS-801 (EGFR inhibitor).
• The firm pursues a clinical-stage biopharmaceutical model focused on discovering, developing, and commercializing targeted oncology therapies; it currently generates no revenue as all assets are in development.
• It serves patients with RAS/MAPK pathway-driven cancers, targeting oncologists, healthcare providers, and research institutions specializing in oncology therapeutics.

Erasca is a clinical-stage biotechnology company headquartered in San Diego, California, with a focus on developing targeted therapies for cancer driven by the RAS/MAPK pathway. The company leverages a robust pipeline of oral inhibitors designed to address significant unmet needs in oncology. Erasca's strategy emphasizes innovation in precision medicine to achieve durable clinical outcomes in challenging cancer indications.

What this transaction means for investors

RTW Investments is leaning in big on Erasca amid some pretty big excitement around ERAS-0015, the company's lead pan-RAS molecular glue program. Earlier this year, Erasca reported encouraging early data showing robust responses in patients with KRAS-driven lung and pancreatic cancers, alongside what management described as a favorable safety profile. CEO Jonathan Lim said the drug's potential as a future "backbone" combination therapy is becoming increasingly clear as clinical development advances ahead of schedule.

The company has also been busy building optionality. Erasca recently expanded collaborations with both Tango Therapeutics (in March) and Merck (this month), positioning ERAS-0015 for combination studies across multiple cancer settings. Several important data readouts are expected between late this year and the first half of 2027.

Just as important, Erasca has the balance sheet to pursue those opportunities. Following an upsized financing completed in January, the company ended March with $408.5 million in cash, cash equivalents, and marketable securities, which management expects will fund operations into the second half of 2028.

Ultimately, the stock's massive gain reflects growing optimism, but future returns will likely depend on whether upcoming trial results continue validating Erasca's strategy of targeting the RAS pathway across multiple cancers.

Jonathan Ponciano has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Argenx Se. The Motley Fool recommends Protagonist Therapeutics. The Motley Fool has a disclosure policy.