Phase 1/2A Study of OTP-01 to Evaluate Safety and Anti‑Tumor Activity in Patients with Advanced Solid Tumors

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What is this study about?

The study focuses on people with advanced solid tumors, which are cancers that have grown beyond their original location. Participants will receive an investigational medicine called OTP-01, a laboratory‑made antibody that simultaneously targets two proteins, PD-1 and VEGFR2. These proteins help cancer cells avoid the immune system and grow new blood vessels; blocking them may allow the body’s defenses to attack the tumor. The purpose of the study is to identify a safe and effective dose of OTP-01 and to observe early signs that it can shrink or control the tumors.

In the first part of the trial, small groups of participants will receive increasing amounts of the drug given by an intravenous infusion (a medicine delivered directly into a vein) to determine how the body tolerates it and to find the dose that seems most promising. Once a recommended dose is set, the second part continues with more participants receiving that dose, while doctors watch for side effects and check how the tumors respond. Tumor changes are measured using a standard method called RECIST v1.1, which compares scans taken before and after treatment to see if the cancer gets smaller, stays the same, or grows.

Throughout the study, participants will have regular medical visits, blood tests, and imaging scans to monitor safety and any signs that the tumor is responding. Researchers will record any adverse events, track how long any tumor shrinkage lasts, and note how long participants remain free from disease progression. The overall goal is to gather information that could lead to larger studies and eventually new treatment options for people with advanced solid tumors.

1 screening and baseline assessments

after joining the study, undergo screening procedures to confirm eligibility for treatment of advanced solid tumors. this includes a review of medical history, physical exam, laboratory tests, and imaging scans to establish baseline tumor measurements.

2 first dose of otp-01

receive the study medication otp-01 by intravenous infusion, which is a liquid administered directly into a vein. the exact dose and frequency are set by the study protocol and may be adjusted during the trial.

3 regular treatment visits

return to the clinic on the schedule defined by the study to receive additional otp-01 infusions. each visit includes observation for any new or worsening adverse events (side effects) and routine safety checks such as blood work and vital‑sign measurements.

4 safety monitoring

at every treatment visit, clinic staff assess the severity and frequency of any adverse events or serious adverse events. laboratory tests are repeated to monitor organ function and overall health.

5 tumor response evaluations

periodically undergo imaging studies (for example, CT or MRI scans) to measure tumor size. results are evaluated using recist v1.1, a standardized method to determine whether the tumor is shrinking, stable, or growing.

6 continuation or discontinuation of therapy

continue receiving otp-01 infusions until one of the following occurs: disease progression as shown by imaging, occurrence of unacceptable adverse events, or completion of the planned treatment period defined by the study.

7 end‑of‑study visit

attend a final visit in which all safety data, tumor measurements, and overall outcomes are collected. this information contributes to the study objectives of determining the recommended phase 2 dose, assessing safety, and evaluating preliminary anti‑tumor activity.

Who Can Join the Study?

Histologically or cytologically confirmed advanced solid tumors – meaning a doctor has examined your tumor tissue or cells under a microscope and diagnosed a solid cancer that cannot be cured, has come back, cannot be removed by surgery, or has spread to other parts of the body.
You must have a type of solid tumor that is listed in the study plan and your disease must have gotten worse after the most recent systemic treatment (such as chemotherapy) or you could not tolerate that treatment.
You should have already tried an approved standard therapy that is known to help, unless it was not suitable for you, caused unacceptable side effects, or you chose not to take it (your decision must be recorded in your medical record).
ECOG performance status 0‑1 – this is a simple scale that measures how well you can carry out daily activities. 0 means fully active, and 1 means you are restricted in physically strenuous activity but can do light work.
A life expectancy of at least 3 months.
Willingness to provide a tumor sample taken before treatment, either from an existing sample in your records or a new small tissue sample (biopsy).
Any side effects from previous cancer treatments must have mostly cleared, leaving only mild (Grade 1) effects according to the NCI CTCAE v5.0 grading system, except for hair loss (alopecia) or nerve problems (neuropathy) which can be up to moderate (Grade 2).
Blood tests must show that your bone marrow (blood‑forming tissue), kidneys, and liver are working well enough for the study.
Additional criteria defined in the study protocol must also be met.
You must have disease that can be measured by the standard RECIST v1.1 criteria (which assess tumor size), and patients with breast or ovarian cancer that have disease that can be evaluated even if not directly measurable are also allowed.

Who Cannot Join the Study?

You have taken strong systemic corticosteroids (steroid medicines that affect the whole body) at a dose higher than 10 mg of prednisone each day within the four weeks before signing the consent form.
You have had a very severe (Grade 4) allergic or anaphylactic reaction to a previous monoclonal antibody drug or to any ingredient in the study medication.
You previously experienced side‑effects from cancer immunotherapy that were serious enough to stop that treatment forever.
You have an active autoimmune disease (a condition where the immune system attacks your own body) that needed systemic (whole‑body) treatment in the past two years (routine hormone replacement does not count).
You have had an organ or stem‑cell transplant, or you need medicines that suppress the immune system (immunosuppressive treatment).
Your urine test showed protein levels higher than 2 + within seven days before starting the study medication (proteinuria means protein in the urine).
You received any chemotherapy, immunotherapy, or experimental cancer treatment within three weeks (or five drug half‑lives, whichever is shorter, with a minimum of two weeks) before the first dose of the study drug.
You had definitive radiation therapy within six weeks, or palliative radiation therapy within two weeks, before the first dose of the study drug; and if you were previously irradiated, the treated areas must have shown clear growth before being counted as target lesions.
Other study‑specific reasons may also make you ineligible to join the trial.

Where you can join this trial?

Verified and Recommended Sites

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Verified Sites

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Other Sites

Site Name	City	Country	Status
Hospital Universitario Fundacion Jimenez Diaz	Madrid	Spain

Trial status

Country	Status	Recruitment Start
Ireland	Recruiting	08.04.2026
Portugal	Recruiting	08.04.2026
Spain	Recruiting	08.04.2026

Trial locations

OTP-01 is an experimental antibody that is designed to block two proteins, PD‑1 and VEGFR2, which tumors often use to grow and avoid the immune system. In this study participants receive OTP‑01 through an intravenous (IV) infusion. The main goals are to find a safe dose for later trials, see how well patients tolerate the drug, and look for any signs that the tumor shrinks or stops growing. By targeting both PD‑1 and VEGFR2 at the same time, OTP‑01 aims to boost the body’s natural ability to fight cancer while also cutting off blood vessels that feed the tumor.

Advanced solid tumor – A solid tumor is a mass of abnormal cells that develops in organs or tissues such as the lung, breast, colon, or bone. When the tumor grows larger and spreads to nearby structures or distant sites, it is described as advanced. The disease often starts as a localized growth that gradually enlarges and infiltrates surrounding tissue. Over time, cancer cells may enter the bloodstream or lymphatic system and form new tumors in other parts of the body. This spread increases the overall disease burden and is tracked by changes in size and location on imaging studies.

Trial ID:

2025-524111-37-00

Trial Phase:

Phase I and Phase II (Integrated) – First administration to humans

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Phase 1/2A Study of OTP-01 to Evaluate Safety and Anti‑Tumor Activity in Patients with Advanced Solid Tumors

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?