Cocrystal Pharma Receives IRB Approval from Emory University School of Medicine for Phase 1b Human Challenge Study with CDI-988 for Prevention and Treatment of Norovirus

Rhea-AI Summary

Cocrystal Pharma (Nasdaq: COCP) received Institutional Review Board approval from Emory University School of Medicine to start a Phase 1b human challenge study of CDI-988 for prevention and treatment of norovirus.

Key facts: the study follows FDA IND clearance and a Study May Proceed letter, will enroll up to 40 healthy adults (ages 18-49), use norovirus GII.2 challenge, and expects subject enrollment in Q1 2026. Primary endpoint is reduction in clinical symptoms; secondary endpoints include viral shedding and disease severity.

Positive

• Emory IRB approval secured on Dec 18, 2025
• FDA IND clearance and a Study May Proceed letter obtained
• Favorable Phase 1 safety/tolerability across dose cohorts through 1200 mg
• First oral broad‑spectrum norovirus antiviral targeting conserved 3CL protease

Negative

• Phase 1b trial size limited to up to 40 subjects
• Study restricted to healthy adults ages 18–49
• No efficacy results reported yet from the Phase 1b challenge study

Key Figures

Study start target Q1 2026 Enrollment for Phase 1b norovirus human challenge study

Phase 1b subjects Up to 40 healthy subjects Randomized, double-blind, placebo-controlled study at Emory University

Subject age range 18–49 years Eligibility criteria for Phase 1b norovirus challenge study

Prior max dose 1200 mg Highest CDI-988 dose with favorable Phase 1 safety and tolerability

Global norovirus burden 700 million cases each year Estimated worldwide annual norovirus infections cited in release

Virus strain GII.2 (Snow Mountain Virus) Norovirus strain used to infect participants in challenge study

Key viral targets GII.4 and GII.17 Norovirus genogroups targeted via 3CL protease inhibition

IRB approval institution Emory University School of Medicine Site granting IRB approval for Phase 1b challenge study

Market Reality Check

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Common Catalyst Peer Athira Pharma also had a clinical-development headline, but broader sector trading appears stock-specific rather than a unified biotech move.

Historical Context

Date	Event	Sentiment	Move	Catalyst
Dec 01	Conference presentation	Neutral	-2.8%	Announcement of Noble Capital conference presentation and webcast details.
Nov 14	Earnings and pipeline	Negative	+0.0%	Q3 2025 results with going concern language and pipeline status updates.
Oct 30	Insider private placement	Positive	+1.9%	Insider-led private placement with warrants to support development programs.
Oct 27	NIH grant award	Positive	+4.2%	Non-dilutive NIH/NIAID SBIR Phase I award for influenza program.
Oct 02	Conference presentation	Neutral	-3.2%	Virtual Noble Capital conference appearance and investor meetings.

Pattern Detected

Recent news around financings, grants and clinical progress has produced modest, mixed price reactions, with positive pipeline or insider events sometimes aligning with gains while conference updates have coincided with small pullbacks.

Recent Company History

Over the past few months, Cocrystal issued multiple updates spanning financing, pipeline, and investor outreach. An October 2025 NIH SBIR award for influenza and insider-funded private placement were followed by small positive reactions. Q3 2025 results on Nov 14 detailed tighter liquidity and going‑concern language alongside antiviral pipeline progress, with a flat price response. Conference presentation announcements on Oct 2 and Dec 1 saw mild declines. Today’s IRB approval for the CDI‑988 norovirus Phase 1b challenge study builds directly on the earlier FDA IND clearance noted in the Q3 filings.

Market Pulse Summary

This announcement details IRB approval at Emory for a Phase 1b human challenge study of CDI‑988 in norovirus, with enrollment targeted for Q1 2026 and up to 40 healthy adults. It builds on prior FDA IND clearance and favorable Phase 1 safety up to 1200 mg. Historically, Cocrystal’s news flow has mixed pipeline progress with tight liquidity disclosures and insider financings. Investors may watch study initiation, early efficacy signals, and future funding steps as key next datapoints.

Key Terms

institutional review board regulatory

"announces the approval from the Institutional Review Board (IRB) at Emory"

An institutional review board is an independent committee that reviews and approves research involving people to make sure studies are safe, ethical, and protect participants’ rights and privacy. For investors, IRB approval is a gatekeeper: it can determine whether a clinical trial can start or continue, affecting timelines, regulatory risk, cost and the credibility of trial results—similar to a safety inspector whose sign-off is required before work can proceed.

phase 1b medical

"to initiate a Phase 1b human challenge study with CDI-988"

"Phase 1b" is an early stage in testing a new medical treatment or vaccine, where it is given to a small group of people to evaluate its safety and determine the right dose. For investors, this phase signals progress in development, indicating the treatment is advancing through initial safety checks, which can influence expectations for future success and potential market impact.

human challenge study medical

"to initiate a Phase 1b human challenge study with CDI-988"

A human challenge study is a medical trial in which consenting volunteers are intentionally exposed to a virus, bacteria, or other agent under controlled conditions to test how well a vaccine or treatment works. For investors it matters because these studies can speed up or clarify whether a product is effective—like a controlled crash test for a new drug—while also carrying higher ethical, safety and regulatory risk that can affect timelines, approvals, costs and company reputation.

investigational new drug regulatory

"including U.S. Food and Drug Administration (FDA) clearance of its investigational New Drug (IND) application"

An investigational new drug is a medication that is still being tested in clinical trials to determine if it is safe and effective for treating a specific condition. For investors, it represents a potential breakthrough that could lead to a new treatment and significant financial gains if successful, but also carries risks since it has not yet been approved for widespread use.

broad-spectrum inhibitor medical

"designed as a broad-spectrum inhibitor by targeting a highly conserved region"

A broad-spectrum inhibitor is a drug or compound that blocks the activity of multiple related biological targets, such as several strains of a virus, types of bacteria, or a group of related enzymes in the body. For investors, it matters because one product that works across many targets can reach a larger market and reduce reliance on pinpoint accuracy, similar to a multi-tool that replaces several single-use gadgets, but it may also face broader safety and regulatory scrutiny.

3cl protease medical

"targeting a highly conserved region of the viral 3CL protease of all noroviruses"

3CL protease is an enzyme viruses use to cut long viral protein chains into the smaller parts needed to assemble new virus particles; it is often called the “main protease.” Investors care because blocking this molecular scissors can stop viral replication, making 3CL protease a prime drug target for antiviral therapies. Think of it like disabling the key machine on a factory line—successful inhibitors can create value by enabling effective treatments.

double-blind medical

"The randomized, double-blind, placebo-controlled Phase 1b study will be conducted"

A double-blind process means that neither the people conducting an activity nor the people involved know certain key details, such as who is receiving a treatment or a placebo. This approach helps prevent bias from influencing the results, making the outcome more trustworthy. For investors, it ensures that decisions or judgments are based on unbiased information rather than preconceived opinions or expectations.

pharmacokinetic medical

"The study will also assess the safety and pharmacokinetic profile of CDI-988"

Pharmacokinetic describes how a drug moves through and leaves the body — how it is absorbed, spread to tissues, broken down and excreted — like tracking a package from pickup to delivery and disposal. For investors, these properties determine effective dose, safety risks, how often a medicine must be taken, and how reliably it works, which in turn influence clinical trial success, regulatory approval chances, production complexity and a drug’s commercial value.

AI-generated analysis. Not financial advice.

• Subject enrollment expected to begin in Q1 2026
• CDI-988 is the first oral broad-spectrum antiviral drug candidate for potential prevention of norovirus outbreaks and treatment of acute viral gastroenteritis caused by norovirus infection
• There are no approved treatments or vaccines currently available for norovirus infection
  

BOTHELL, Wash., Dec. 18, 2025 (GLOBE NEWSWIRE) -- Cocrystal Pharma, Inc. (Nasdaq: COCP) (“Cocrystal” or the “Company”) announces the approval from the Institutional Review Board (IRB) at Emory University School of Medicine to initiate a Phase 1b human challenge study with CDI-988. This study aims to evaluate CDI-988 as both a preventive and treatment for norovirus infections. Initial screening of study subjects is currently underway, with enrollment expected to begin in the first quarter of 2026. The IRB approval from Emory University School of Medicine follows Cocrystal’s prior regulatory milestones, including U.S. Food and Drug Administration (FDA) clearance of its investigational New Drug (IND) application.

CDI-988 is the first oral antiviral drug candidate developed for the prevention and treatment of norovirus acute gastroenteritis. It was specifically designed as a broad-spectrum inhibitor by targeting a highly conserved region of the viral 3CL protease of all noroviruses, including GII.4 and recently re-emerging GII.17.

The randomized, double-blind, placebo-controlled Phase 1b study will be conducted at Emory University and involve up to 40 healthy subjects ages 18-49. Participants will be screened and infected with the norovirus GII.2 (Snow Mountain Virus). The study’s primary efficacy endpoint is to assess the reduction in incidence of clinical symptoms, while the secondary efficacy endpoint focuses on the reduction in viral shedding and disease severity. The study will also assess the safety and pharmacokinetic profile of CDI-988. Additional information is available on clinicaltrials.gov.

“This approval from the Emory IRB marks a significant milestone in advancing our Phase 1b norovirus challenge study,” said Sam Lee, Ph.D., Cocrystal’s President and co-CEO. “We are very excited about collaborating with the Emory team, given their exceptional expertise in norovirus and experience in human challenge studies.

“Cocrystal’s norovirus challenge study is a critical step in addressing the global burden of norovirus outbreaks, which account for an estimated 700 million cases each year worldwide. We are committed to delivering innovative medicine for norovirus outbreaks and chronic norovirus infection among immunocompromised patients,” added Dr. Lee.

“CDI-988 may revolutionize the management of the highly contagious norovirus, which is known for quickly spreading in hospitals, nursing homes, cruise ships, schools, disaster relief sites, military settings and other semi-closed environments,” said James Martin, CFO and co-CEO. “Used as a prophylaxis, oral CDI-988 could offer a potential solution and add a new layer of defense.”

CDI-988 was designed with Cocrystal’s proprietary structure-based drug discovery platform technology. In August 2025 Cocrystal announced favorable Phase 1 safety and tolerability data from all CDI-988 dose cohorts including the highest dose of 1200 mg. In September 2025 the Company received a Study May Proceed Letter from the FDA for the Phase 1b challenge study.

About Norovirus

Norovirus is a common and highly contagious virus that afflicts people of all ages and causes symptoms of acute gastroenteritis including nausea, vomiting, stomach pain and diarrhea, as well as fatigue, fever and dehydration. This debilitating illness causes an estimated 200,000 deaths worldwide each year, with a societal cost of approximately $60 billion. In the U.S., norovirus is responsible for about 21 million cases of acute gastroenteritis annually, including 109,000 hospitalizations, 465,000 emergency department visits and nearly 900 deaths, with an estimated annual economic burden of $10.6 billion.

Cocrystal Pharma’s Structure-Based Drug Discovery Platform Technology

Cocrystal’s proprietary structural biology, along with its expertise in enzymology and medicinal chemistry, enable its development of novel antiviral agents. The Company’s platform provides a three-dimensional structure of inhibitor complexes at near-atomic resolution, providing immediate insight to guide Structure Activity Relationships. This helps identify novel binding sites and enables a rapid turnaround of structural information through highly automated X-ray data processing and refinement. The goal of this technology is to facilitate the development of novel broad-spectrum antivirals for the treatment of acute, chronic and potentially pandemic viral diseases.

About Cocrystal Pharma, Inc.

Cocrystal Pharma, Inc. is a clinical-stage biotechnology company discovering and developing novel antiviral therapeutics that target the replication process of influenza viruses, coronaviruses (including SARS-CoV-2), noroviruses and hepatitis C viruses. Cocrystal employs unique structure-based technologies to create viable antiviral drugs. For further information about Cocrystal, please visit www.cocrystalpharma.com.

Cautionary Note Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, including statements regarding our initiation of the norovirus study in the first quarter of 2026 and the potential of CDI-988 for norovirus infections. The words "believe," "may," "estimate," "continue," "anticipate," "intend," "should," "plan," "could," "target," "potential," "is likely," "will," "expect" and similar expressions, as they relate to us, are intended to identify forward-looking statements. We have based these forward-looking statements largely on our current expectations and projections about future events. Some or all of the events anticipated by these forward-looking statements may not occur. Important factors that could cause actual results to differ from those in the forward-looking statements include, but are not limited to, the risks and uncertainties arising from inflation, affordability, the possibility of a recession, the impact of future interest rate changes on the economy, tariffs and the resulting litigation, and geopolitical conflicts including those in Ukraine and Middle East on our Company, our collaboration partners, and on the U.S. and global economies, including manufacturing and research delays arising from raw materials and labor shortages, supply chain disruptions and other business interruptions including any adverse impacts on our ability to obtain raw materials for and otherwise proceed with the planned norovirus study or subsequent studies as well as similar problems with our vendors and our current and any future clinical research organizations (CROs) and contract manufacturing organizations (CMOs), the progress and results of the studies including any adverse findings or delays, the ability of us and our CROs to recruit volunteers for, and to otherwise proceed with, clinical studies, our and our collaboration partners’ technology and software performing as expected, financial difficulties experienced by certain partners, the results of any current and future preclinical and clinical studies, general risks arising from clinical studies, receipt of regulatory approvals, regulatory changes and any adverse developments which may arise therefrom, potential mutations in a virus we are targeting that may result in variants that are resistant to a product candidate we develop, the potential for the development of effective treatments by competitors which could reduce or eliminate a prospective future market share commercializing any product candidates we may develop in the future, and our ability to meet our future liquidity needs. Further information on our risk factors is contained in our filings with the SEC, including the “Risk Factors” in Item 1A of our Annual Report on Form 10-K for the year ended December 31, 2024 and the Prospectus dated September 25, 2025. Any forward-looking statement made by us herein speaks only as of the date on which it is made. Factors or events that could cause our actual results to differ may emerge from time to time, and it is not possible for us to predict all of them. We undertake no obligation to publicly update any forward-looking statement, whether as a result of new information, future developments or otherwise, except as may be required by law.

Contact:

Alliance Advisors IR
Jody Cain
310-691-7100
jcain@allianceadvisors.com

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FAQ

What did Cocrystal (COCP) announce about the CDI-988 Phase 1b study on Dec 18, 2025?

Cocrystal announced Emory University IRB approval to start a randomized, double‑blind, placebo‑controlled Phase 1b norovirus challenge study with enrollment expected in Q1 2026.

When will subject enrollment for COCP's CDI-988 Phase 1b study begin?

Initial screening is underway and subject enrollment is expected to begin in Q1 2026.

What are the primary and secondary endpoints of the CDI-988 Phase 1b study (COCP)?

Primary endpoint: reduction in incidence of clinical symptoms; secondary endpoints: reduction in viral shedding and disease severity.

How many participants and what virus strain will COCP use in the CDI-988 challenge study?

The study will involve up to 40 healthy subjects (ages 18–49) and use norovirus GII.2 (Snow Mountain Virus).

Has CDI-988 shown safety in earlier trials reported by Cocrystal (COCP)?

Yes; in August 2025 Cocrystal reported favorable Phase 1 safety and tolerability across all CDI-988 dose cohorts, including the 1200 mg dose.

What regulatory milestones has COCP achieved for CDI-988 prior to the Phase 1b study?

Cocrystal secured FDA IND clearance and received a Study May Proceed letter ahead of the Emory IRB approval.