Sponsor: Portage Biotech (industry)
Phase: 1/2
Start date: June 23, 2023
Planned enrollment: 90
TT-4 is an oral small‑molecule antagonist of the adenosine A2B receptor (A2BR) being developed by Tarus Therapeutics for cancer immunotherapy. An IND for TT‑4 was cleared by the FDA in May 2021. A first‑in‑human Phase 1/2 study (NCT04976660) was registered to evaluate TT‑4 in advanced solid tumors, but the trial was later listed as withdrawn/not active and no results have been posted as of October 7, 2025. (itbusinessnet.com)
Note: Several background reviews on adenosine pathway targeting (A2A/A2B) provide additional context but do not report TT‑4 clinical results. (mdpi.com)
Last updated: Oct 2025
TT-10 (PORT-6) is an oral, selective adenosine A2A receptor (A2AR) antagonist being developed for immuno-oncology. It originated at Tarus Therapeutics (as TT-10) and is now being developed by Portage Biotech (renamed PORT-6). A Phase 1/2, first‑in‑human study (ADPORT‑601; NCT04969315) is evaluating PORT‑6 alone, with a companion A2B antagonist (PORT‑7/TT‑4), and in combination, across selected advanced solid tumors (notably mCRPC, RCC, and NSCLC). As of 2025, the study is in dose escalation with enrollment resumed in March 2025 after a funding‑related pause. (accessnewswire.com)
Note: TT‑10 (PORT‑6) in oncology is distinct from an unrelated preclinical “TT‑10” reported in cardiology literature for cardiomyocyte proliferation.
Adenosine accumulates in hypoxic tumor microenvironments and suppresses anti‑tumor immunity via A2A (on T and NK cells) and A2B (largely myeloid) receptors. PORT‑6 selectively blocks A2A signaling to counter adenosine‑mediated immunosuppression; the ADPORT‑601 program also explores selective A2B blockade (PORT‑7) and dual blockade. (ascopubs.org)
Publicly available human efficacy results (e.g., objective response rate, duration of response) have not been reported as of October 7, 2025. An ASCO 2024 abstract noted that updated safety/efficacy/PK data would be presented and emphasized the biologic rationale (including bone‑metastatic mCRPC) but did not include response rates in the published abstract text. (ascopubs.org)
If additional peer‑reviewed clinical data (e.g., response rates) become available from ADPORT‑601, those results can be incorporated once published or presented with extractable details.
Last updated: Oct 2025
Goal: Evaluate safety, tolerability, and preliminary antitumor activity of TT-10 (PORT-6, an A2A receptor antagonist), TT-4 (PORT-7, an A2B receptor antagonist), and their combination; determine MTD/RP2D for each regimen and estimate early efficacy in advanced solid tumors lacking standard options.
Patients: Adults ≥18 years with histologically/cytologically confirmed advanced solid tumors after or ineligible for standard therapies. Phase Ia dose-escalation cohorts: TT-10 in RCC, mCRPC, NSCLC, SCCHN; TT-4 in CRC, mCRPC, NSCLC, endometrial, and ovarian cancers. Combination cohort includes one or more of these tumor types per safety monitoring committee guidance. ECOG 0–1, measurable disease per RECIST 1.1 (exceptions for PSA-only mCRPC with approval), adequate marrow, hepatic, and renal function, ability to swallow capsules, and willingness for baseline biopsy unless exceptions apply. Key exclusions include active CNS/leptomeningeal disease (unless treated/stable without steroids), recent major surgery/radiation/systemic therapy, need for strong CYP3A4/2C9/2C19 modulators or acid-reducing agents, significant cardiac/pulmonary GI risk factors, active infections, and pregnancy/breastfeeding.
Design: Multicenter, open-label, nonrandomized Phase I/II study with dose escalation followed by expansion. Three parallel dose-escalation cohorts (TT-10, TT-4, and TT-10+TT-4) to define MTD/RP2D, then expansion at RP2D to further characterize safety and preliminary efficacy.
Treatments: TT-10 (PORT-6) is an oral small-molecule antagonist of the adenosine A2A receptor designed to reverse adenosine-mediated immunosuppression in hypoxic tumor microenvironments. Preclinical data show high-affinity binding with slow dissociation and monotherapy activity in murine tumor models. Early clinical safety from the ongoing program has reported mainly grade 1–2 AEs without dose-limiting toxicities to date in a small cohort; full efficacy remains investigational. Dosing is oral BID in 28-day cycles with ascending dose levels. TT-4 (PORT-7) is an oral small-molecule antagonist of the adenosine A2B receptor intended to block adenosine-driven immunosuppression and protumorigenic signaling; human efficacy data are not yet established. Dosing is oral QD in 28-day cycles with ascending dose levels or adjusted frequency. The combination arm administers TT-10 plus TT-4 orally with dose levels informed by monotherapy safety, aiming to assess dual adenosine receptor blockade.
Outcomes: Primary: incidence of dose-limiting toxicities during dose escalation; determination of MTD/RP2D; and, in expansion, incidence and severity of treatment-related adverse events (CTCAE v5.0). Secondary: overall response rate per RECIST 1.1, duration of response, progression-free survival, and pharmacokinetics of TT-10 (Cmax, AUC, half-life) with intensive sampling around dosing.
Burden on patient: High. As a first-in-human Phase I/II with oral agents, patients should expect frequent on-site visits in early cycles, intensive PK blood draws at multiple time points (predose through 24 hours), mandated baseline tumor biopsy or recent archival tissue, and regular safety labs and imaging per RECIST. Concomitant medication restrictions (strong CYP modulators and acid-reducing agents) may necessitate regimen changes. Combination dosing and potential dose escalations add monitoring complexity. Travel frequency is greater than standard care early in treatment, though pill administration is at home once dosing is established.
Last updated: Oct 2025
To be eligible for inclusion in the dose escalation cohorts or expansion cohorts in this study, participants must meet all of the following criteria:
1. Participants must be ≥18 years of age.
2. Participants or their legal representative must be able to provide written informed consent to participate in the study prior to the performance of any study-specific procedures.
3. Diagnosis of histologically or cytologically confirmed advanced selected solid tumors:
Cohort A - TT-10 dose escalation:
1. RCC: Participants with locally advanced or metastatic RCC that have previously received at least two prior systemic regimens, including vascular endothelial growth factor (VEGF)-targeted therapy and checkpoint inhibitor therapy
2. CRPC: Participants with metastatic CRPC who have previously received a second-generation hormonal agent (unless contraindicated) and a taxane-based chemotherapy.
3. SCCHN: Participants with advanced or metastatic SCCHN that is incurable by surgery or radiotherapy and that has progressed during or after a platinum-based chemotherapy and/or checkpoint inhibitor therapy (separately or in combination)
4. NSCLC: Participants with metastatic NSCLC that is intolerant or resistant to standard therapy or for which no standard therapy is available
Cohort B - TT-4 dose escalation:
1. CRC: Participants with metastatic CRC that is intolerant or resistant to standard therapy or for which no standard therapy is available
2. CRPC: Participants with metastatic CRPC who have previously received a second-generation hormonal agent (unless contraindicated) and a taxane-based chemotherapy
3. NSCLC: Participants with metastatic NSCLC that is intolerant or resistant to standard therapy or for which no standard therapy is available
4. Endometrial cancer: Participants with metastatic endometrial cancer that is intolerant or resistant to standard therapy or for which no standard therapy is available
5. Ovarian cancer: Participants with metastatic ovarian cancer that is intolerant or resistant to standard therapy or for which no standard therapy is available
Cohort C- TT-10 + TT- 4 dose escalation and expansion:
a. The tumor types will include 1 or more of those enrolled in the respective Escalation Cohorts (A and B), and will be determined following review of the dose escalation data by the SMC.
4. Eastern Cooperative Oncology Group (ECOG) performance status (PS) score 0 - 1
5. Have measurable disease per RECIST 1.1 as assessed by the local site investigator/radiology. Lesions situated in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions.
a. Participants with CRPC who have metastatic disease that is non-measurable are eligible if screening PSA ≥ 2.0 ng/mL and with Sponsor approval
6. Failure to respond to standard therapy, or for whom no appropriate therapies are available (based on the judgment of the investigator)
7. Consent to baseline biopsy, with the following exceptions:
1. Participants whose only site(s) of disease are in areas considered moderate or high risk may be enrolled without a fresh biopsy with Sponsor approval;
2. Archival tissue may be submitted in lieu of a fresh biopsy if collected within 6 months of screening and without intervening systemic therapy.
8. Participants must have adequate hematologic function based on the following:
* ANC ≥ 1.5 x 109/L
* Platelet count ≥ 100 x 109/L
* Hemoglobin ≥ 9.0 g/dL
9. Participants must have adequate hepatic function based on the following:
* Total bilirubin \< 1.5 x upper limit of normal (ULN) (unless elevated due to Gilbert's syndrome)
* ALT/AST ≤ 2.5 x ULN (≤ 5 x ULN for participants with known hepatic metastases)
10. Participants must have adequate renal function based on the following:
* Serum creatinine ≤ 1.5 x ULN; or
* Serum creatinine clearance ≥ 60 mL/min, as determined by Cockcroft-Gault equation
11. For women of childbearing potential (WCBP): negative urine pregnancy test (UPT) within 1 week before first treatment (WCBP defined as a sexually mature woman who has not undergone surgical sterilization or who has not been naturally post-menopausal for at least 12 consecutive months for women \> 55 years of age). WCBP should be placed on effective birth control directly after testing negative for pregnancy; if not, then WCBP should have a UPT on Day 1 of every cycle, prior to study intervention administration. Any positive or indeterminant UPT result must be confirmed by serum.
a. Female participants of childbearing potential must use a highly effective mode of contraception or abstain from heterosexual activity for the duration of the study and for 120 days following the last dose of study intervention. A female is NOT of childbearing potential if she has undergone bilateral salpingoophorectomy or is menopausal, defined as an absence of menses for 12 consecutive months. Male participants must agree to use highly effective contraception.
12. Ability to adhere to the study visit schedule and all protocol requirements
13. Must be able to swallow capsules
Participants will be excluded from the study if they satisfy any of the following criteria at the Screening visit unless otherwise stated:
Participants are to be excluded from the study if they meet any of the following criteria:
1. Major surgery within 4 weeks prior to Screening
2. Participants with active CNS metastases; however, participants who have undergone radiation and/or surgery for the treatment of CNS metastases, who are neurologically stable and who are no longer taking pharmacologic doses of corticosteroids are eligible; participants with leptomeningeal metastases are not eligible.
3. Has received prior radiotherapy within 2 weeks of start of study intervention. Participants must have recovered from all radiation-related toxicities, not require corticosteroids and not have had radiation pneumonitis. A 1-week washout is permitted for palliative radiation (≤ 2 weeks of radiotherapy) to non-CNS disease.
4. Prior anti-cancer therapy within 4 weeks prior to the start of study intervention. A 2 week washout is acceptable for short-acting drugs (eg, tyrosine kinase inhibitors). Any treatment-related toxicities must be resolved to Grade 0 - 1.
5. Human immunodeficiency virus (HIV)-infected participants
6. Participants who are hepatitis B surface antigen positive are eligible if they have received hepatitis B virus (HBV) antiviral therapy for at least 4 weeks and have undetectable HBV viral load prior to enrollment.
Note: Participants should remain on antiviral therapy throughout study intervention and follow local guidelines for HBV antiviral therapy post completion of study intervention.
Hepatitis B screening tests are not required unless:
* Known history of HBV infection
* As mandated by local health authority
7. Participants with a history of hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable at Screening. Note: Participants must have completed curative antiviral therapy at least 4 weeks prior to enrollment.
Hepatitis C screening tests are not required unless:
* Known history of HCV infection
* As mandated by local health authority
8. Participants who require immunosuppressive therapy including, but not limited to, treatment with corticosteroids in pharmacologic doses (equivalent to ≥ 10 mg prednisone daily), cyclosporine, mycophenolate, azathioprine, methotrexate, adalimumab, infliximab, vedolizumab, tofacitinib, dupilumab, rituximab, etc. or systemic steroids (except for steroid use as cortisol replacement therapy in documented adrenal insufficiency)
9. Participants requiring administration of drugs known to be strong inhibitors or inducers of CYP3A4, 2C9 or 2C19
10. Participants requiring drugs that modify gastric pH, such as proton-pump inhibitors (PPIs) or H2 blockers. Antacids, such as calcium carbonate or aluminum hydroxide-based products, will be allowed during the study, but are recommended to be taken either 4 hours before or 2 hours after dosing of TT 10 (PORT 6) or PORT-7.
11. Ongoing systemic bacterial, fungal or viral infections at Screening
a. NOTE: Participants on antimicrobial, antifungal or antiviral prophylaxis are not specifically excluded if all other inclusion/exclusion criteria are met
12. Administration of a live vaccine within 6 weeks of first dose of study intervention. Messenger ribonucleic acid (mRNA) vaccines for the prevention of Coronavirus Disease 2019 (COVID-19) infection are permitted.
13. Baseline QT interval corrected with Fridericia's method (QTcF) \> 470 ms (average of triplicate readings)
a. NOTE: Criterion does not apply to participants with a right or left bundle branch block.
14. Prior surgery or gastrointestinal dysfunction that may affect drug absorption (eg, gastric bypass surgery, gastrectomy)
15. Female participants who are pregnant or breastfeeding
16. Concurrent active malignancy other than non-melanoma skin cancer, carcinoma in situ of the cervix or prostate intraepithelial neoplasia
17. Past medical history of interstitial lung disease, drug-induced interstitial lung disease, radiation pneumonitis which required steroid treatment, or any evidence of clinically active interstitial lung disease
18. History of peptic ulcer and/or gastrointestinal bleed within the past 6 months prior to Screening
19. History of stroke, unstable angina, myocardial infarction or ventricular arrhythmia requiring medication or mechanical control within the last 6 months prior to Screening
20. Unstable or severe uncontrolled medical condition (eg, unstable cardiac function, unstable pulmonary condition including pneumonitis and/or interstitial lung disease, uncontrolled diabetes) or any important medical illness or abnormal laboratory finding that would, in the investigator's judgment, increase the risk to the participant associated with his or her participation in the study
Los Angeles, California, 90033, United States
No email / No phone
Status: Recruiting
Louisville, Kentucky, 40241, United States
No email / No phone
Status: Recruiting
Houston, Texas, 77030, United States
No email / No phone
Status: Recruiting