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

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 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 , on SEDAR+ at  and on EDGAR at . Follow Theratechnologies on  and .

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  and on EDGAR at  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.

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