Up to $400,000,000

Common Stock

We have previously entered into a Sales Agreement, or the sales agreement, with Leerink Partners LLC, or Leerink Partners, dated November 21, 2025, relating to the sale of shares of our common stock, par value $0.001 per share. We previously filed a prospectus supplement on November 21, 2025, relating to the offer and sale of shares of our common stock having an aggregate offering price of up to $100,000,000 from time to time through Leerink Partners, acting as our sales agent, or the prior prospectus supplement. As of the date of this prospectus supplement, we have sold an aggregate amount of approximately $64,389,566 of shares of our common stock under the prior prospectus supplement pursuant to the sales agreement. We are terminating the offering pursuant to the prior prospectus supplement and we will not make any further offer or sale of shares of our common stock pursuant to the prior prospectus supplement.

We are filing this prospectus supplement in accordance with the terms of the sales agreement, relating to the offer and sale of shares of our common stock having an aggregate offering price of up to $400,000,000 from time to time through Leerink Partners acting as our sales agent.

Our common stock is listed on The Nasdaq Global Market under the symbol "TNGX." On August 10, 2026, the closing sale price of our common stock on The Nasdaq Global Market was $27.67 per share.