OS Therapies Announces Phase 2b Clinical Trial of OST-HER2 Achieves Primary Endpoint with Statistical Significance in the Prevention of Recurrent, Fully Resected, Lung Metastatic Osteosarcoma
OS Therapies (NYSE-A: OSTX) announced positive results from its Phase 2b clinical trial of OST-HER2, showing statistically significant outcomes in treating recurrent, fully resected, lung metastatic osteosarcoma. The trial achieved its primary endpoint with 33.3% event-free survival (EFS) at 12 months compared to 20% historical control (p=0.0158).
The study demonstrated promising interim results for overall survival (OS), with 91% one-year survival and 61% two-year survival rates, compared to historical controls of 80% and 40% respectively. All patients achieving 12-month EFS remain alive in follow-up. The trial included 39 evaluable patients aged 12-39 years across 21 centers, with treatment consisting of 16 doses over 48 weeks.
Post-hoc analyses revealed higher EFS rates in females (47%) compared to males (20%), and better outcomes in patients with multiple prior lung resections (55%) versus single resection (25%). The treatment demonstrated a favorable safety profile in this population with no currently approved therapies.
OS Therapies (NYSE-A: OSTX) ha annunciato risultati positivi dal suo trial clinico di Fase 2b per OST-HER2, mostrando risultati statisticamente significativi nel trattamento dell'osteosarcoma metastatico polmonare ricorrente, completamente resecato. Lo studio ha raggiunto il suo obiettivo primario con un 33,3% di sopravvivenza libera da eventi (EFS) a 12 mesi rispetto al 20% del controllo storico (p=0.0158).
La ricerca ha dimostrato risultati intermedi promettenti per la sopravvivenza complessiva (OS), con tassi di 91% di sopravvivenza a un anno e 61% di sopravvivenza a due anni, rispetto ai controlli storici dell'80% e del 40% rispettivamente. Tutti i pazienti con EFS a 12 mesi sono rimasti in vita durante il follow-up. Il trial ha incluso 39 pazienti valutabili di età compresa tra 12 e 39 anni in 21 centri, con un trattamento composto da 16 dosi distribuite su 48 settimane.
Le analisi post-hoc hanno rivelato tassi di EFS più elevati nelle femmine (47%) rispetto ai maschi (20%), e risultati migliori nei pazienti con più resezioni polmonari precedenti (55%) rispetto a una singola resezione (25%). Il trattamento ha mostrato un profilo di sicurezza favorevole in questa popolazione, senza terapie attualmente approvate.
OS Therapies (NYSE-A: OSTX) anunció resultados positivos de su ensayo clínico de Fase 2b de OST-HER2, mostrando resultados estadísticamente significativos en el tratamiento del osteosarcoma metastásico pulmonar recurrente y completamente resecado. El ensayo alcanzó su objetivo principal con un 33,3% de supervivencia libre de eventos (EFS) a 12 meses en comparación con el 20% del control histórico (p=0.0158).
El estudio demostró resultados intermedios prometedores para la supervivencia global (OS), con tasas de 91% de supervivencia a un año y 61% de supervivencia a dos años, en comparación con los controles históricos del 80% y el 40% respectivamente. Todos los pacientes que alcanzaron EFS a 12 meses siguen vivos en el seguimiento. El ensayo incluyó 39 pacientes evaluables de entre 12 y 39 años en 21 centros, con un tratamiento que consistió en 16 dosis durante 48 semanas.
Los análisis post-hoc revelaron tasas de EFS más altas en mujeres (47%) en comparación con hombres (20%), y mejores resultados en pacientes con múltiples resecciones pulmonares anteriores (55%) frente a una sola resección (25%). El tratamiento demostró un perfil de seguridad favorable en esta población, sin terapias actualmente aprobadas.
OS Therapies (NYSE-A: OSTX)는 OST-HER2의 2b상 임상시험에서 긍정적인 결과를 발표했습니다. 이 시험에서는 재발성, 완전 절제된 폐 전이 골육종 치료에서 통계적으로 유의미한 결과를 보여주었습니다. 이 시험은 12개월 동안의 사건 발생 없는 생존율(EFS) 33.3%을 목표로 했고, 역사적 대조군의 20% (p=0.0158)와 비교되었습니다.
연구는 전체 생존율(OS)에서 유망한 중간 결과를 보여주었고, 1년 생존율 91% 및 2년 생존율 61%을 기록했으며, 이는 역사적 대조군의 각각 80% 및 40%와 비교됩니다. 12개월 EFS에 도달한 모든 환자는 추적 조사에서 생존했습니다. 이 시험은 21개 센터에서 12세에서 39세 사이의 39명의 평가 가능한 환자를 포함했으며, 치료는 48주에 걸쳐 16회의 투여로 구성되었습니다.
사후 분석 결과, 여성의 EFS 비율이 47%로 남성의 20%보다 높았으며, 다수의 폐 절제력을 가진 환자(55%)가 단일 절제(EFS 25%)보다 더 나은 결과를 보여주었습니다. 이 치료법은 현재 승인된 치료법이 없는 인구 집단에서 유리한 안전성 프로필을 보여주었습니다.
OS Therapies (NYSE-A: OSTX) a annoncé des résultats positifs de son essai clinique de phase 2b de l'OST-HER2, montrant des résultats statistiquement significatifs dans le traitement de l'ostéosarcome pulmonaire métastatique récurrent, complètement réséqué. L'essai a atteint son objectif principal avec un 33,3 % de survie sans événement (EFS) à 12 mois par rapport à 20 % dans le contrôle historique (p=0.0158).
L'étude a démontré des résultats intermédiaires prometteurs pour la survie globale (OS), avec des taux de 91 % de survie à un an et 61 % de survie à deux ans, par rapport aux contrôles historiques de 80 % et 40 % respectivement. Tous les patients atteignant un EFS à 12 mois sont restés en vie lors du suivi. L'essai a inclus 39 patients évaluables âgés de 12 à 39 ans dans 21 centres, le traitement consistant en 16 doses réparties sur 48 semaines.
Les analyses post-hoc ont révélé des taux d'EFS plus élevés chez les femmes (47 %) par rapport aux hommes (20 %), et de meilleurs résultats chez les patients ayant subi plusieurs résections pulmonaires antérieures (55 %) par rapport à une seule résection (25 %). Le traitement a montré un profil de sécurité favorable dans cette population, sans thérapies actuellement approuvées.
OS Therapies (NYSE-A: OSTX) hat positive Ergebnisse aus seiner Phase 2b-Studie zu OST-HER2 bekannt gegeben, die statistisch signifikante Ergebnisse bei der Behandlung von rezidivierendem, vollständig resezierten, lungemetastasiertem Osteosarkom zeigt. Die Studie erreichte ihr primäres Endziel mit einer Ereignis-freien Überlebensrate (EFS) von 33,3 % nach 12 Monaten im Vergleich zu 20 % in der historischen Kontrollgruppe (p=0.0158).
Die Studie zeigte vielversprechende vorläufige Ergebnisse für das Gesamtüberleben (OS) mit einer einjährigen Überlebensrate von 91% und einer zwei jährigen Überlebensrate von 61%, im Vergleich zu historischen Kontrollen von 80 % und 40 %. Alle Patienten mit EFS von 12 Monaten sind im Follow-up noch am Leben. Die Studie umfasste 39 bewertbare Patienten im Alter von 12 bis 39 Jahren an 21 Zentren, wobei die Behandlung aus 16 Dosen über 48 Wochen bestand.
Post-hoc-Analysen zeigten höhere EFS-Raten bei Frauen (47 %) im Vergleich zu Männern (20 %), sowie bessere Ergebnisse bei Patienten mit mehreren vorausgehenden Lungenresektionen (55 %) im Vergleich zur Einzelresektion (25 %). Die Behandlung zeigte ein positives Sicherheitsprofil in dieser Population ohne derzeit zugelassene Therapien.
- Achieved primary endpoint with 33.3% 12-month EFS vs 20% historical control (p=0.0158)
- Strong interim OS data: 91% 1-year and 61% 2-year survival vs 80% and 40% historical control
- 100% survival rate among patients achieving 12-month EFS
- Favorable safety profile in treatment population
- Potential for accelerated FDA approval pathway
- Lower EFS response in male patients (20%) compared to females (47%)
- Non-significant results in some post-hoc analyses (p>0.05)
Insights
The Phase 2b clinical trial results for OST-HER2 represent a significant breakthrough in osteosarcoma treatment. The trial achieved its primary endpoint with a
The interim survival data is equally compelling -
This positive clinical data significantly strengthens OS Therapies' market position and potential revenue trajectory. With a market cap of
The strong efficacy data and clear regulatory pathway could attract strategic partnerships or acquisition interest from larger pharmaceutical companies seeking to expand their rare disease portfolios. For investors, this represents a potential inflection point - successful commercialization in this orphan indication could drive significant value creation, particularly given the current absence of approved treatments in this space.
-
The primary endpoint of 12-month Event Free Survival (EFS) for OST-HER2- treated patients (
33.3% ) was statistically significant (p= 0.0158) when compared with peer-reviewed comparable historical control (20% ) - Ongoing follow up demonstrates strong trend in favor of OST-HER2 in 1-year and 2-year interim analyses of the secondary endpoint, 3-year overall survival (OS) when compared with comparable peer-reviewed historical control
-
100% of patients who achieved 12-month EFS remain alive in OS follow-up - OST-HER2 was safe and well tolerated in the Phase 2b study
- OS Therapies reiterates clinical and regulatory path in recurrent, fully respected osteosarcoma with lung metastases, an indication with no currently approved treatments
“We are extremely pleased with these results of our Phase 2b clinical trial because they show that OST-HER2-treated patients achieved the primary endpoint of 12-month EFS in a statistically significantly higher ratio than comparable historical controls, in addition to increasing the likelihood of 1-year and 2-year survival as compared with comparable historical controls,” commented Dr. Robert Petit, Chief Medical & Scientific Officer of OS Therapies. “The strong safety profile shown in this study also supports the use of OST-HER2 in this incredibly difficult-to-treat population that has no currently approved therapies.”
“The achievement of the primary endpoint in the OST-HER2 phase 2b is a tremendous success that opens the possibility, for the first time, of meaningful therapy for patients suffering from osteosarcoma with lung metastases after resection. This is a leap forward in the development of OST-HER2 and we are pleased that our regulatory strategy is consistent with the FDA’s recent draft guidance update for accelerated approvals. With these positive data in hand, we are preparing to engage with
Phase 2b Clinical Trial Data
Enrollment Criteria:
- 12-39 years old
- Recurred, fully resected lung only metastatic (METS) Osteosarcoma
- 39 evaluable patients at 21 centers, single treatment arm
- 52 Weeks on Study: Dosed 16 times every 3 weeks for 48 weeks with 4-week follow-up final visit
Primary Endpoint of 12-month EFS:
-
33% for OST-HER2 vs.20% for historical control1 (p = 0.0158)
Interim Analysis of Ongoing Secondary Endpoint, OS:
-
1-year OS:
91% for OST-HER2 vs.80% for historical control2 (p = 0.0700) -
2-year OS:
61% for OST-HER2 vs.40% for historical control2 (p = 0.0576)
Post-Hoc Analyses
12-months EFS Subgroup Analysis in the OST-HER2 Treatment Group:
Gender (Males vs Females), n = 39:
-
Females (n=19) =
47% -
Males (n= 20) =
20%
(p= 0.0604)
Number of lung resections (1 Prior Resection vs. 2+ Prior Resections), n= 39:
-
1 Prior Resection (n= 28) =
25% -
2+ Prior Resections (n= 11) =
55%
(p = 0.1366)
12-month EFS Responders using a Non-Concurrent Control Group from the only existing US osteosarcoma database with patients qualified for disease-free status following a fully-resected lung-only metastasis of osteosarcoma origin:
-
OST-HER2, n=39
12-month EFS Responders = 13/39 (33% )
-
NCCG, n=9
12-month EFS Responders = 1/9 (11% )
(p = 0.1848)
Time to recurrence in patients who did not achieve 12-month EFS:
- OST-HER2, n=26 = 5.9 months
-
NCCG, n=8 = 4.7 months
(p = 0.1454)
About OST-HER2
OST-HER2 is an innovative immunotherapy using a HER2 bioengineered form of the bacteria Listeria monocytogenes (Lm) to trigger a strong immune response against cancer cells expressing HER2. This off-the-shelf immunotherapy treatment is designed to prevent metastasis, delay recurrence, kill primary tumors expressing HER2 alone and potentially in combination with existing approved therapies, and increase overall survival. OST-HER2 has received Rare Pediatric Disease Designation (RPDD) from the FDA and Fast Track and Orphan Drug Designations from the FDA and European Medicines Agency (EMA).
The US FDA granted OST-HER2 rare pediatric disease designation for osteosarcoma in 2021. The US FDA rare pediatric disease PRV program aims to incentivize drug development for rare pediatric diseases. Under this voucher program, a sponsor who receives an approval for a drug or biological product for a rare pediatric disease qualifies for a voucher that can be redeemed to receive priority review for a different product. The sponsor may also transfer or sell the voucher to another sponsor. OS Therapies intends to sell the PRV it would earn upon receiving an approval of OST-HER2 for recurrent, fully resected, lung metastatic osteosarcoma. The most recent publicly disclosed sale price of a PRV was on November 27th, 2024 when PTC Therapeutics announced selling its PRV to Kebilidi for
The most recent continuing resolution (CR) negotiations in the US House of Representatives failed to reauthorize the PRV program for pediatric cancers such as osteosarcoma. Despite this, as a result of OS Therapies’ having been granted OST-HER2’s rare pediatric disease designation prior to December 20, 2024 in addition to the Company’s aim to receive an approval for OST-HER2 in the rare pediatric disease osteosarcoma in 2025, prior to the September 30, 2026 deadline, OS Therapies remains eligible to receive the PRV upon approval of OST-HER2 in recurrent, resected metastatic osteosarcoma.
The osteosarcoma treatment market was estimated at
About OS Therapies
OS Therapies is a clinical stage oncology company focused on the identification, development, and commercialization of treatments for Osteosarcoma (OS) and other solid tumors. OST-HER2, the Company's lead asset, is an immunotherapy leveraging the immune-stimulatory effects of Listeria bacteria to initiate a strong immune response targeting the HER2 protein. The Company has completed enrollment for a 41-patient Phase 2b clinical trial of OST-HER2 in resected, recurrent osteosarcoma, with results expected in the fourth quarter of 2024. OST-HER2 has completed a Phase 1 clinical study primarily in breast cancer patients, in addition to showing preclinical efficacy data in various models of breast cancer. OST-HER2 has been conditionally approved by the
Forward-Looking Statements
Statements in this press release about future expectations, plans and prospects, as well as any other statements regarding matters that are not historical facts, may constitute forward-looking statements within the meaning of the federal securities laws. These forward-looking statements and terms such as "anticipate," "expect," "intend," "may," "will," "should" or other comparable terms involve risks and uncertainties because they relate to events and depend on circumstances that will occur in the future. Those statements include statements regarding the intent, belief or current expectations of OS Therapies and members of its management, as well as the assumptions on which such statements are based. OS Therapies cautions readers that forward-looking statements are based on management’s expectations and assumptions as of the date of this news release and are subject to certain risks and uncertainties that could cause actual results to differ materially, including, but not limited to the approval of OST-HER2 by the US FDA and grant of a priority review voucher and other risks and uncertainties described in “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in the Company’s registration statement on Form S-1 filed with the Securities and Exchange Commission (the “SEC”) on November 12, 2024, as amended on November 27, 2024, and other subsequent documents we file with the SEC, including but not limited to our Quarterly Reports on Form 10-Q. Any forward-looking statements contained in this press release speak only as of the date hereof, and, except as required by the federal securities laws, OS Therapies specifically disclaims any obligation to update any forward-looking statement, whether as a result of new information, future events or otherwise.
1 Lagmay JP, Krailo MD, Dang H, et al: Outcome of patients with recurrent osteosarcoma enrolled in seven Phase II trials through Children's Cancer Group, Pediatric Oncology Group, and Children's Oncology Group: learning from the past to move forward. J Clin Oncol. 2016;34:3031-8
2 A.H. Aljubran, A. Griffin, M. Pintilie, M. Blackstein; Osteosarcoma in adolescents and adults: survival analysis with and without lung metastases; Annals of Oncology; Volume 20, Issue 6; 2009;1136-41
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OS Therapies Contact Information:
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Irpr@ostherapies.com
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Source: OS Therapies, Inc.
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