Theratechnologies Presents Encouraging Virologic Suppression Data from the PROMISE-US Trial of Ibalizumab at CROI

Rhea-AI Summary

Theratechnologies (NASDAQ: THTX) presented encouraging data from the PROMISE-US trial of ibalizumab for HIV treatment at CROI 2025. The real-world observational study demonstrated that patients receiving ibalizumab-containing regimens achieved similar viral suppression rates compared to control groups, despite having more severe baseline conditions.

The interim analysis included 112 participants (70 in control Cohort 1, 42 in ibalizumab Cohort 2). Among viremic patients, 47% in the ibalizumab group achieved undetectable viral load after 6 months, compared to 50% in controls. At 12 months, undetectable rates were 42% for ibalizumab versus 53% for controls.

Notably, ibalizumab-treated patients started with more challenging baseline characteristics, including lower CD4 counts and higher viral loads. The drug demonstrated good tolerability with no infusion reactions or treatment discontinuations due to adverse events.

Positive

• Demonstrated efficacy in treating severe HIV cases with similar viral suppression rates to controls
• Strong safety profile with no infusion reactions or treatment discontinuations
• Successfully treated patients with more challenging baseline characteristics

Negative

• Slightly lower 12-month viral suppression rate (42%) compared to control group (53%)

Insights

Infectious Disease Specialist

The PROMISE-US trial data presented by Theratechnologies at CROI 2025 offers meaningful clinical validation for ibalizumab in heavily treatment-experienced (HTE) HIV patients with multidrug resistance. The results demonstrate that ibalizumab-containing regimens achieved comparable virologic suppression rates to control treatments, despite the ibalizumab group having significantly worse baseline disease characteristics.

What makes these findings particularly notable is the context: patients in the ibalizumab cohort had lower CD4 counts and higher baseline viral loads, yet still achieved undetectable viral loads (47% at 6 months, 42% at 12 months) statistically similar to the control group (50% and 53% respectively). The clean safety profile with no reported infusion reactions or treatment discontinuations due to adverse events further strengthens ibalizumab's clinical utility.

From a commercial perspective, this real-world evidence reinforces ibalizumab's position in a specialized but critical market segment. While the HTE population represents a relatively small subset of HIV patients, these individuals have treatment options and typically require more intensive healthcare resources. The data helps secure ibalizumab's place in treatment protocols and potentially supports reimbursement decisions for this premium-priced therapy.

For Theratechnologies, these results represent an incremental positive that validates an existing revenue stream rather than opening entirely new markets. As the first registry capturing long-term outcomes in this population, PROMISE-US provides clinicians with confidence in ibalizumab's durability and reinforces its role as a vital component in constructing effective regimens for multidrug-resistant HIV.

Results show similar levels of virus undetectability in patients on ibalizumab-containing regimens as in controls, despite greater baseline severity of HIV

Ibalizumab continues to demonstrate long-term efficacy and safety as part of combination antiretroviral therapy in heavily treatment-experienced people with multidrug resistant HIV

MONTREAL, March 12, 2025 (GLOBE NEWSWIRE) -- Theratechnologies Inc. (“Theratechnologies” or the “Company”) (TSX: TH) (NASDAQ: THTX), a commercial-stage biopharmaceutical company, today presented data from a real-world, observational, registry study demonstrating the efficacy and safety of ibalizumab in reducing HIV RNA to undetectable levels in heavily treatment-experienced (HTE) patients with multidrug resistant HIV.

In a poster session at the 2025 Conference on Retroviruses and Opportunistic Infections (CROI) in San Francisco, Calif., investigators from the Prospective Observational Study of Multidrug-Resistant Patient Outcomes with and without Ibalizumab in a Real-World Setting: United States (PROMISE-US) reported that patients treated with regimens containing ibalizumab achieved undetectable HIV viral load levels at similar rates as those receiving non-ibalizumab-containing regimens, despite displaying characteristics indicative of more severe HIV disease at baseline.

“The availability of long-term injectable therapies has not eliminated the phenomenon of multidrug resistance, and heavily treatment-experienced people with HIV deserve fully suppressive antiretroviral regimens that can help them establish and maintain virologic control,” stated presenting author Smitha Gudipati, MD, an infectious disease specialist at Henry Ford Hospital in Detroit, Mich. “We are therefore encouraged to see such impressive reductions in viremia in patients whose regimens include ibalizumab, despite having lower CD4 counts and higher viral loads at baseline than the non-ibalizumab control group.”

Theratechnologies previously announced the study design and baseline characteristics of participants in PROMISE-US (ClinicalTrials.gov identifier: NCT05388474), a phase 4, multicenter, retrospective and prospective, observational, non-interventional registry study. The trial is designed to assess risk factors and predictors of virologic and immunologic response in HTE people with HIV (PWH) and specific sub-populations. Its primary objective is to evaluate the long-term efficacy and durability of ibalizumab, a CD4-directed post-attachment inhibitor of HIV, in combination with other antiretroviral therapies by comparing the clinical outcomes of patients receiving ibalizumab (Cohort 2) versus matched patients not receiving ibalizumab (Cohort 1).

At CROI, the PROMISE-US investigators presented an interim, unmatched subgroup analysis comprising 112 participants, of whom 70 were enrolled in Cohort 1 and 42 in Cohort 2. At baseline, 27 of participants in Cohort 1 and 25 in Cohort 2 were viremic, defined as viral load above 50 RNA copies/mL (39% and 57%, respectively; p=0.0279). Three-quarters (74%) of participants in Cohort 1 who had baseline viremia had more than 200 CD4 T-cells/mm³ at baseline, compared to only 44% of those in Cohort 2 who were viremic at baseline (p=0.0376).

Among those with baseline viremia, 50% of Cohort 1 participants and 47% in Cohort 2 achieved undetectable viral load (≤50 RNA copies/mL) after six months of treatment (p=0.873). At 12 months, viral load was undetectable in 53% of Cohort 1 participants and in 42% of those in Cohort 2 (p=0.0.524). Ibalizumab was well-tolerated with no infusion reactions reported and no discontinuation of treatment by participants in Cohort 2 due to a treatment emergent adverse event.

“The PROMISE-US trial is the first registry to capture long-term clinical outcomes for highly treatment-experienced patients with multidrug-resistant HIV in a real-world setting and in the US specifically,” commented Christian Marsolais, Ph.D., Senior Vice President and Chief Medical Officer of Theratechnologies. “The data presented today suggest that ibalizumab can be a critical component of therapeutic regimens in the modern antiretroviral era. We look forward to validating these interim findings as we continue to enroll and monitor patients in this ongoing study.”

About Theratechnologies

Theratechnologies (TSX: TH) (NASDAQ: THTX) is a specialty biopharmaceutical company focused on the commercialization of innovative therapies that have the potential to redefine standards of care. Further information about Theratechnologies is available on the Company's website at www.theratech.com, on SEDAR+ at www.sedarplus.ca and on EDGAR at www.sec.gov. Follow Theratechnologies on Linkedin and X.

Forward-Looking Information

This press release contains forward-looking statements and forward-looking information (collectively, the “Forward-Looking Statements”), within the meaning of applicable securities laws, that are based on our management’s beliefs and assumptions and on information currently available to our management. You can identify Forward-Looking Statements by terms such as “may”, “will”, “should”, “could”, “promising”, “would”, “outlook”, “believe”, “plan”, “envisage”, “anticipate”, “expect” and “estimate”, or the negatives of these terms, or variations of them. The Forward-Looking Statements contained in this press release include, but are not limited to, statements regarding the long-term safety and efficacy of ibalizumab, the effect of ibalizumab on the reductions of viremia and the use of ibalizumab as a component of therapeutic regimens in the modern antiretroviral era. Forward-looking statements involve a number of assumptions, risks and uncertainties. Some of these assumptions include, but are not limited to, the fact that patients receiving ibalizumab will achieve undetectable HIV viral load levels. The Company refers current and potential investors to the “Risk Factors” section of its Annual Information Form filed under the Company’s Form 20-F dated February 26, 2025 available on SEDAR+ at www.sedarplus.ca and on EDGAR at www.sec.gov under Theratechnologies’ public filings for the risks associated with the business of Theratechnologies. The reader is cautioned to consider these and other risks and uncertainties carefully and not to put undue reliance on forward-looking statements. Forward-Looking Statements reflect current expectations regarding future events and speak only as of the date of this press release and represent the Company’s expectations as of that date.

The Company undertakes no obligation to update or revise the information contained in this press release, whether as a result of new information, future events or circumstances or otherwise, except as may be required by applicable law.

Contacts:

Media inquiries:
Julie Schneiderman
Senior Director, Communications & Corporate Affairs
communications@theratech.com
1-514-336-7800

Investor Inquiries:
Joanne Choi
Senior Director, Investor Relations
jchoi@theratech.com
1-551-261-0401

FAQ

What were the key findings of THTX's PROMISE-US trial for ibalizumab presented at CROI 2025?

The trial showed ibalizumab-containing regimens achieved similar viral suppression rates (47% at 6 months) compared to controls (50%), despite treating patients with more severe baseline HIV conditions.

How many patients were included in the PROMISE-US trial interim analysis for THTX's ibalizumab?

The interim analysis included 112 participants: 70 in control Cohort 1 and 42 in the ibalizumab-treated Cohort 2.

What was the 12-month viral suppression rate for THTX's ibalizumab in the PROMISE-US trial?

At 12 months, 42% of patients in the ibalizumab group achieved undetectable viral load, compared to 53% in the control group.

What safety results were reported for THTX's ibalizumab in the PROMISE-US trial?

Ibalizumab was well-tolerated with no infusion reactions reported and no treatment discontinuations due to adverse events.