Form 4: Cambrian BioPharma Sells SNSE Shares Under 10b5-1 Plan

Cambrian BioPharma Inc., a 10% owner of Sensei Biotherapeutics, Inc., reported multiple sales of common stock totaling 6,612 shares on December 9, 2025, alongside an option exercise, pursuant to a Rule 10b5-1 plan.

Summary

• Cambrian BioPharma Inc., a 10% owner of Sensei Biotherapeutics, Inc. (SNSE), reported transactions on December 9, 2025, under a Rule 10b5-1 plan.
• The reporting person exercised a stock option to acquire 395 shares of common stock at an exercise price of $6.40 per share.
• Following the option exercise, Cambrian BioPharma Inc. sold a total of 6,612 shares of Sensei Biotherapeutics common stock in multiple transactions.
• Sales included 3,105 shares at a weighted average price of $8.59 (ranging from $8.50 to $9.00), 2,666 shares at a weighted average price of $7.95 (ranging from $7.80 to $8.33), 395 shares at $8.04, and 446 shares at a weighted average price of $7.92 (ranging from $7.91 to $7.95).
• After these transactions, Cambrian BioPharma Inc. directly holds 155,142 shares of Sensei Biotherapeutics common stock.
• The stock option for 395 shares, with an exercise price of $6.40, was fully exercised, resulting in 0 derivative securities beneficially owned by the reporting person.
• The option was adjusted for a 1-for-20 stock split effectuated by the issuer and vests in 12 equal monthly installments over one year, fully vested on May 21, 2026, or the date of the Company's next annual stockholder meeting, subject to continuous service.

Sentiment

Score: 5

Explanation: The sentiment is neutral. While a 10% owner sold shares, the transactions were conducted under a pre-arranged Rule 10b5-1 plan, which typically indicates a scheduled liquidity event rather than a reaction to new, negative information about the company. The option exercise and subsequent sales also show a profitable transaction for the insider.

Positives

• The exercise of stock options at $6.40 per share and subsequent sales at higher prices (ranging from $7.92 to $9.00) indicate a profitable transaction for the reporting person.

Negatives

• The net disposition of 6,217 shares by a 10% owner could be perceived as a slight negative signal, although it was conducted under a pre-arranged Rule 10b5-1 plan.

Future Outlook

NA

Management Comments

• James Peyer, Chief Executive Officer of Cambrian BioPharma Inc., may direct the voting and disposition of shares held by Cambrian, subject to Board approval in certain instances, and disclaims beneficial ownership of such shares.

Industry Context

NA

Key Dates

Recommendation

The reported transactions are routine insider sales executed under a pre-arranged Rule 10b5-1 plan. Such sales are generally not indicative of new material information regarding the company's prospects and are often for personal financial planning. Therefore, this filing alone does not provide a strong basis for a 'buy' or 'sell' recommendation, suggesting a 'hold' position for investors awaiting more substantive company-specific news or financial results.

Keywords

Sensei Biotherapeutics, SNSE, Cambrian BioPharma, Insider Trading, Form 4, Stock Sale, Option Exercise, 10% Owner, Rule 10b5-1 Plan