This study is being done to see how effective and safe four doses of the experimental drug oregovomab is when given through a vein in your arm at the same time as specific cycles of the chemotherapy regimen paclitaxel and carboplatin.

If you have ovarian cancer and are able to participate in this research study, you would have already gone through surgery to remove as much cancer as possible. You are either getting ready to start your first round (or cycle) of chemotherapy after this surgery or you will be resuming chemotherapy after taking three rounds (or cycles) of chemotherapy and having undergone surgery to remove as much cancer as possible.

The Sponsor is trying to answer the following question in this clinical research study:

• After you have had surgery to remove as much of your cancer as possible, will adding experimental drug oregovomab to the usual approach of using the chemotherapies (paclitaxel and carboplatin) prolong the time that you are cancer free?

The usual approach is defined as the care most people get for ovarian cancer (see section below called "What is the usual approach to my ovarian cancer?").

The usual approach for patients diagnosed with ovarian cancer is treatment with surgery, and/or anti-cancer drugs.

Surgical options may include surgery to remove as much cancer as possible cancer – a procedure called "debulking".

There are several chemotherapy and other anti-cancer drugs approved for use in your country that are commonly used.

You also may have been offered one or more of the following treatments: paclitaxel, carboplatin, cisplatin, docetaxel, bevacizumab, gemcitabine, liposomal doxorubicin, and others. Sometimes, combinations of these treatments are used. In some countries, the treatment may be called by another name. Your doctor can explain which treatment may be best for you.

In addition, if you no longer want to pursue treatment or there are no available treatment options for you, supportive care may be provided to improve your quality of life. It may include alleviating any health issues or symptoms caused by cancer treatments. This approach is sometimes also known as palliative care.

Therefore, it is important that you discuss all your options with your Study Doctor before deciding whether you will participate in this clinical research study.

• You may choose to have the usual approach described above.
• You may choose to take part in a different research study, if one is available.
• You may choose not to be treated for cancer.
• You may choose to only get care to help relieve your symptoms and not get treated for your cancer.

If you decide not to take part in this study, your Study Doctor will suggest alternative therapies available for your further treatment. You should discuss the risks and benefits of those with your Study Doctor.

Your physician will determine which cohort you belong to based on when you had your debulking surgery and whether you are getting ready to start chemotherapy or to resume chemotherapy after already taking three rounds (or cycles) of chemotherapy. Following this process, you will be randomized to either one of the two study groups – an experimental group and a placebo group.

First, your Study Doctor will use a computer to assign you to one of the treatment groups by chance like the flip of a coin. This process is called “randomization.” It means that your doctor will not choose, and you cannot choose in which study group you will get placed. Your doctor will also not know which group you will get placed. This is called “double-blind”, which means that you, your study doctor or the study staff will not know whether you are taking oregovomab or placebo until the end of the study. If your safety is at risk, your study doctor can find out what you are receiving. Another way to find out what will happen to you during this study is to read the chart below. Start reading at the left side and read across to the right, following the lines and arrows.

If you meet the study requirements, you will be given study drug at specific times up to 24 weeks during the treatment period. After stopping study drug, your Study Doctor will check on you every 3 months for 2 years after treatment. After that, they will check on you every 6 months for the third year and beyond. This means you could keep seeing the Study Doctor for 3 years or more after stopping the study drug. Patients may be in trial for upto 3.5 years, and the study may take upto 4-5 years to complete.

It is currently not known if you will receive any benefit by taking part in this clinical study. If you decide to take part, your disease and overall condition will be closely evaluated by your Study Doctor. The information from this study will help researchers learn more about oregovomab as treatment for cancer. This information may help future cancer subjects.

There may be risks of side-effects from study treatment (study drug or study chemotherapy drugs) on this study or from some of the procedures or tests that will be done. Also, your cancer condition may get better, but it could stay the same or even get worse.

Below you will find the most common side effects doctors know about for the study drug (oregovomab) being studied and the chemotherapy drugs (paclitaxel and carboplatin). Keep in mind that there might be other side effects doctors do not yet know about. If important new side effects are found, the Study Doctor will discuss these with you.

Oregovomab known side effects when given alone:

Infusion-related reactions are the most common side effects known for the study drug oregovomab when it is taken alone. Infusion-related reactions include reactions such as flushing (warmth and reddening of skin), rash, fever, rigors (feeling of cold with shivering), chills, shortness of breath, and mild low blood pressure. Infusion-related reactions were seen in 20% or more of the patients who received the drug in the past, but for the majority of the cases, they were mild, easily managed and generally prevented when pre-medications were taken by patients before they received oregovomab.

Side effects of combination (Oregovomab, paclitaxel and carboplatin):

There have been several different side effects seen in previous studies when oregovomab was given with paclitaxel and carboplatin. Possible side effects could include Anemia (person does not have enough healthy red blood cells to carry adequate oxygen to his or her body's tissues), Leukopenia (person has fewer white blood cells in their bloodstream than they should), Neutropenia (person has a low level of white blood cells called neutrophils), Thrombocytopenia (person has low platelet levels), Asthenia (weakness), Fatigue, Nausea, Constipation, Diarrhea, Vomiting, Paresthesia (tingling ‘pins and needles’ feeling), Peripheral sensory neuropathy (nerve damage outside of the brain and spinal cord, often causes weakness, numbness and pain, usually in your hands and feet), and Alopecia (hair loss). The more uncommon side effects seen in less than 5% of patients include arthralgia (joint pain) and myalgia (muscle pain).

Yes, you are free to stop taking part in the study at any time and without giving a reason. If you decide to stop, let your Study Doctor know as soon as possible. It is important that you stop safely.

If you choose to stop taking the study drug before the study ends, you should discuss the following options with the Study Doctor:

• You can stop taking the study drug but continue to visit the Study Doctor for study related procedures or tests.
• You can stop the study but allow the Study Doctor or the study staff to collect information about your health by reviewing your medical records, by contacting you, a family member, or a legal representative.
• Even if you decide to completely leave the study and the Study Doctor cannot reach you, official public sources will be consulted where allowed to verify your well-being and to use this information for the study.
• You can completely leave the study and have no more contact with the Study Doctor and the study staff for study related procedures or questions as of the date of your request.

If you stop taking part in the study, no new additional information will be collected from you. You may be requested to undergo an end of study assessment for your safety. Your Study Doctor may ask if they can continue to contact you to see how you are doing. You can decide if you want to keep letting the Study Doctor know how you are doing.

Withdrawing from taking part in the study will not affect the standard of care you receive.

Taking part in this study is your choice. No matter what decision you make, and even if your decision changes, there will be no penalty to you and the quality of your care will not be affected. You will not lose medical care or any legal rights by signing this informed consent form.