If You Invested in HilleVax, Inc. (HLVX)

HilleVax, Inc. (Nasdaq: HLVX) is a clinical-stage biopharmaceutical company that has focused on the development and commercialization of novel vaccines. The company is associated with the biological product manufacturing sector and has concentrated its efforts on vaccine candidates targeting norovirus-related acute gastroenteritis (AGE), a significant cause of gastrointestinal illness worldwide.

According to multiple company disclosures, HilleVax’s initial and most advanced programs have been HIL-214 and HIL-216. These are described as virus-like particle (VLP) based vaccine candidates in development for the prevention of moderate-to-severe acute gastroenteritis caused by norovirus infection. Company materials note that the burden of norovirus falls disproportionately on young children and older adults, and that norovirus is associated with a very large number of AGE cases and substantial direct and societal costs globally.

HIL-214 has been highlighted in company communications as HilleVax’s most advanced norovirus vaccine program. It has been evaluated in clinical studies in adults and infants, including the NEST-IN1 Phase 2b clinical study in infants and other trials in adults. In July 2024, HilleVax reported that the NEST-IN1 study in infants did not meet its primary or secondary efficacy endpoints and stated that it would discontinue further development of HIL-214 in infants while exploring potential continued development of HIL-214 and HIL-216 in adults.

Throughout its public updates in 2024 and 2025, HilleVax described itself as a clinical-stage company, meaning its vaccine candidates were undergoing clinical testing and had not been described in the provided materials as approved commercial products. The company’s communications emphasize ongoing evaluation of strategic alternatives and business development activities related to its norovirus vaccine candidates, particularly in adult populations.

Corporate transaction and change in status

On August 4, 2025, HilleVax announced that it had entered into a definitive merger agreement with XOMA Royalty Corporation (XOMA Royalty). Under this agreement, XOMA Royalty agreed to acquire all issued and outstanding shares of HilleVax common stock for $1.95 in cash per share plus a non-transferable contingent value right (CVR) for each share, as described in the merger-related press release and subsequent SEC filings. The CVR provides a contractual right to potential future cash payments tied to specified items, including certain remaining cash, savings on a Boston office lease, and potential proceeds from any future sale, transfer, license or other disposition of remaining norovirus vaccine programs, subject to the terms of a Contingent Value Rights Agreement.

According to the company’s Form 8-K dated September 17, 2025, Parent (XOMA Royalty) and its acquisition subsidiary completed a tender offer and subsequent merger, resulting in XOMA Royalty’s wholly owned subsidiary merging with and into HilleVax. At the effective time of the merger, the separate existence of the acquisition subsidiary ceased and HilleVax continued as the surviving corporation and a wholly owned subsidiary of XOMA Royalty. Each outstanding share of HilleVax common stock (with specified exceptions) was automatically cancelled and converted into the right to receive the cash consideration and CVR described in the merger documentation.

In connection with the completion of the merger, HilleVax notified The Nasdaq Global Select Market of the transaction and requested that Nasdaq file a Form 25 to remove HilleVax’s common stock from listing and registration under Section 12(b) of the Securities Exchange Act of 1934. The Form 25 filed on September 17, 2025, identifies HilleVax, Inc. as the issuer and The Nasdaq Stock Market LLC as the exchange, and relates to the company’s common stock. Subsequently, on September 29, 2025, HilleVax filed a Form 15 to terminate the registration of its common stock under Section 12(g) of the Exchange Act and to suspend its duty to file periodic reports under Sections 13 and 15(d). The Form 15 notes that the approximate number of holders of record as of the certification date was one.

As a result of these steps, HilleVax’s common stock was delisted from Nasdaq and the company terminated its registration and periodic reporting obligations for that class of securities. HilleVax continues to exist as a corporate entity, but as disclosed in the 8-K, it operates as a wholly owned subsidiary of XOMA Royalty Corporation rather than as an independent, exchange-listed public company.

Business focus and development activities

Across its public communications, HilleVax has consistently described its business focus as the development and commercialization of novel vaccines, with a particular emphasis on norovirus vaccines. Its VLP-based vaccine candidates, including HIL-214 and HIL-216, have been developed for the prevention of moderate-to-severe AGE caused by norovirus infection. Company disclosures reference clinical trials such as NEST-IN1 in infants and earlier adult studies, and they describe ongoing evaluation of potential development paths in adults and related business development activities.

HilleVax’s disclosures also highlight that norovirus is estimated to cause a very large number of acute gastroenteritis cases and substantial global health system and societal costs, and that the burden is particularly high among young children and older adults. These contextual statements are presented by the company to explain the rationale for focusing on norovirus vaccine candidates.

HLVX stock and investor considerations

The ticker symbol HLVX historically represented HilleVax, Inc. common stock on The Nasdaq Global Select Market. Following the completion of the tender offer and merger with XOMA Royalty, and the subsequent filing of Form 25 and Form 15, HilleVax’s common stock has been removed from listing on Nasdaq and deregistered under the Exchange Act. The company’s SEC filings describe this as part of the process of becoming a wholly owned subsidiary of XOMA Royalty and ending its status as an independently listed public company.

For users researching HLVX, the symbol now primarily serves as a historical reference to HilleVax’s period as a Nasdaq-listed clinical-stage biopharmaceutical company focused on norovirus vaccine candidates and to the corporate transaction in which it was acquired by XOMA Royalty Corporation.