CompletedPhase IInterventional

A Phase Ia/Ib study of STA551 as a single agent and in combination with atezolizumab in patients with solid tumors

Researchers are testing a new immunotherapy drug called STA551 for adults with advanced solid tumour cancers. Immunotherapy uses the body's natural defences to fight cancer cells. STA551 is designed to turn on immune cells mainly inside tumour tissue, which may help limit damage to healthy parts of the body. This early-stage study is for people whose cancer has spread or grown, and for whom standard treatments are no longer working or suitable. Patients will receive STA551 on its own, or together with an established immunotherapy called atezolizumab. A small group may also receive a special imaging dye to help scans track immune cells. Because this is an early phase trial, the main goals are to check the drug's safety, look for side effects, find the right dose, and see if it helps shrink tumours.

At a glance

Status

Completed

Phase

Phase I

Sponsor

Chugai Pharmaceutical Co., Ltd. (Japan)

Enrolment target

233

Start

11 Mar 2020

Estimated completion

12 Aug 2025

Locally advanced or metastatic solid tumors

What is this study about?

Cancer remains very difficult to treat once it spreads to other parts of the body. In recent years, immunotherapy has changed cancer care by helping the body's own immune system find and attack cancer cells. However, existing treatments do not work for everyone, and new options are urgently needed.

STA551 is a new experimental drug created to boost the immune response. It works by targeting a specific protein called CD137 found on immune cells. By activating this protein, the drug helps immune cells grow, survive, and attack the tumour. What makes STA551 unique is that it is designed to activate mostly within tumour tissue, which doctors hope will lower the risk of unwanted side effects in healthy organs.

In this trial, doctors want to find out how safe STA551 is, how the human body processes it, and what dose works best. They will test it alone and in combination with atezolizumab, an existing immunotherapy medicine. The trial will also observe whether the treatment shows early signs of slowing tumour growth or shrinking tumours in patients with advanced cancer.

Key takeaways

Testing a new immunotherapy drug (STA551) alone and combined with atezolizumab.
Aimed at adults with advanced solid tumours who have run out of standard treatment options.
Focuses mainly on finding a safe dose and checking for side effects.
Treatment is given via a drip in hospital once every three weeks.
Participation is entirely voluntary and you can stop taking part at any time.

Who may be eligible?

This trial is open to adults aged 18 and older who have an advanced solid tumour cancer that has spread locally or to other parts of the body. To take part, standard NHS cancer treatments must have stopped working, caused intolerable side effects, or not be suitable for your situation. You must also be well enough to carry out daily activities and have reasonably healthy liver, kidney, and bone marrow function.

You cannot join this study if you have significant heart problems, such as a heart attack within the last three months, unstable angina, or heart failure. People with a history of autoimmune diseases (where the body attacks its own tissues) are also not eligible, as immunotherapy could make these conditions worse.

Additionally, if you have previously had drugs that target CD137, or if you had to permanently stop previous immunotherapy treatments due to severe side effects, you will not be able to participate.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

I am aged 18 or older.
I have been diagnosed with an advanced or metastatic solid tumour.
Standard treatments for my cancer have stopped working or are not suitable for me.
I am generally mobile and able to look after myself day-to-day.
I do not have a history of serious heart trouble or autoimmune conditions.
I have not had severe reactions to immunotherapy in the past.

Answer every question to see your result.

What does participation involve?

If you take part, you will be placed into one of three treatment groups. You will receive either STA551 on its own, STA551 combined with atezolizumab, or both drugs alongside an imaging dye. Both medicines are given through a drip into a vein every 21 days (three weeks).

You will need to attend regular hospital appointments for check-ups and safety monitoring. These visits will include physical examinations, blood tests, heart checks (ECGs), and monitoring of your blood pressure and temperature. You will also have routine imaging scans, such as CT or MRI scans, to see how your tumour responds to treatment. Those receiving the imaging dye will have additional PET scans.

You can stay on the trial for as long as the treatment is helping you and the side effects remain manageable. The overall study is expected to run until August 2027.

Potential risks and benefits

Because STA551 is a new medicine, there is no guarantee that taking part will improve your cancer. However, the trial will help doctors learn more about treating cancer in the future. As with any new medicine, there are risks of side effects. STA551 can cause liver irritation, allergic reactions during the drip, and immune-related reactions like severe skin rash or itching. Atezolizumab is known to cause tiredness, joint and muscle aches, breathlessness, cough, sickness, and diarrhoea. Because these medicines may harm an unborn baby, reliable contraception is required. Taking part is completely voluntary, and you can leave the trial at any time without your regular NHS medical care being affected.

Locations (2)

Royal Marsden Hospital
Approximate
Sutton, England
The Christie
Approximate
Manchester, England

Common questions

What phase is this trial and what does that mean?

This is a Phase 1 study, which is the earliest stage of human testing. Its main focus is checking safety, finding the right dose, and tracking side effects, rather than proving how well it cures cancer.

Will I have to pay for the trial treatment?

No, the trial drugs and any study-related tests are provided free of charge by the study sponsor.

How often do I need to go to the hospital?

Treatments are given once every three weeks, but you may need extra visits for blood tests, health checks, and scans, particularly during your first few months on the trial.

Can I leave the study if I change my mind?

Yes. You have the right to withdraw from the trial at any time for any reason, and your regular medical team will continue to look after you.

Can I take my usual medications during the trial?

Some medications might interfere with the trial drugs. The study doctor will carefully review everything you take, including over-the-counter tablets and supplements, to make sure they are safe.

How to find out more

Udai Banerji

udai.banerji@icr.ac.uk +44 208 642 6011 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.