Clinical Results Summary
A clinical study to learn about the effects of PLX3397 when given topeople with advanced solid tumors in addition to paclitaxel
Protocol number: PLX108-07

Thank You!

Daiichi Sankyo, Inc., the sponsor of this study, would like to thank the participants who
took part in this study for PLX3397, also known as pexidartinib. Each participant helped toadvance medical research for people affected with advanced solid tumors. Their
contribution to medicine and healthcare is greatly appreciated.

Important note: This summary only shows the results of a single study. Other studies may have different
findings. Researchers and health authorities look at the results of many studies to understand which
treatments work and how they work. It takes a lot of people in many studies around the world to advance
medical science and healthcare.
Do not use the results of this study to make health decisions. Please talk to a doctor before changing any
treatment you are taking or if you have any questions about these study results.

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What was the main purpose of this study?
Advanced solid tumor
A solid tumor is a type of cancer that starts in an organ, muscle, or bone of the body. A tumor is considered tobe “advanced” if it has spread to other parts of the body. The most common symptoms of advanced tumors
are pain, breathing problems, loss of appetite, weight loss, feeling very tired, depression, vomiting, and feelingsick to the stomach. Researchers have found that certain kind of protein called ‘kinase’ helps tumor cells
divide and grow. It is believed that by stopping this protein from working, the growth of the tumor cells can bestopped. PLX3397, also known as pexidartinib, is a study drug that is being tested for its ability to stop thegrowth of tumor cells by preventing this protein from working.
Some types of advanced solid tumors include:•epithelial ovarian cancer develop from the cells that cover the outer surface of the ovary. Ovaries
are female organs that produce eggs.

•primary peritoneal cancer is a rare cancer that develops in a thin layer of tissue that lines thestomach, uterus, bladder, and rectum.

•fallopian cancer starts in the fallopian tubes. Fallopian tubes connect the ovaries to the womb.

All 3 types of cancers are similar and are not easily diagnosed at early stages. At later stages, the symptoms of
all 3 cancers are similar.
A few treatments, such as paclitaxel, are available for advanced solid tumors. However, some people either do
not respond to treatment or their cancer comes back after being treated.
In this study, researchers wanted to learn if giving participants both pexidartinib and paclitaxel together canhelp decrease the size of their tumors.

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Treatments given in this study

Main goals of this study
This study had 3 parts. The main questions the researchers wanted to answer in each part were:Parts 1 and 2:

Part 3:

Other goals of this study
Researchers also wanted to answer the following questions:

Parts 1 and 2:•

How many participants had tumors that completely disappeared or became at least 30% smaller after
treatment?
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•For participants whose tumors completely disappeared or became at least 30% smaller, how long did theeffect of treatment last?

Part 3:•For participants whose tumors completely disappeared or became at least 30% smaller, how long did theeffect of treatment last?

•How long did participants live with their cancer before it got worse or led to death?

Researchers monitored the health of the participants throughout the study.

How long was this study?
The study was designed so that participants could
continue in it as long as their cancer did not get worse, orthey did not have serious side effects, or they did not ask
to be removed.
The study started in May 2012 and ended in June 2017.
The study was completed as planned.

Who was in this study?
The study included 72 participants from 8 study sites in the United States.
Participants could take part in this study if they:•

were at least 18 years of age,•

had an advanced solid tumor (for Parts 1 and 2),•

had advanced epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer (for Part 3),•

had stopped previous therapies at least 15 days before the start of treatment, and•were fully active, OR unable to do a hard physical activity but able to walk and do light housework or office
work, OR unable to work but able to walk and take care of themselves.

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Participants included in this study:

What happened during this study?
This was a Phase 1b study that was divided into 3 parts. Phase 1b studies are sometimes done to find thehighest dose of a drug that can be safely given to participants. This study was also “open-label”. This meansthat both the researchers and the participants knew which treatment was given to which participants.
Part 1 was done to find the highest dose of a pexidartinib that can be safely given to participants in addition topaclitaxel. In Part 2, researchers wanted to see if the highest safe dose of pexidartinib determined in Part 1,
when given in addition to paclitaxel, was effective in reducing tumor size for participants. In Part 3,
researchers were trying to learn if 1200 milligrams (mg) of pexidartinib daily, when given in addition topaclitaxel, can reduce tumor size for participants with epithelial ovarian cancer, primary peritoneal cancer, orfallopian tube cancer.
Participants first completed a screening period to find out if they could take part in the study.

Part 1In Part 1, researchers started by giving the first group of participants 600 mg of pexidartinib daily in addition to80 mg/m2 of paclitaxel once a week. Meter squared, or m2, means the dose of paclitaxel was based on theparticipants’ individual body surface area. If this dose was considered to be safe by the researchers, the nextgroup of participants received a higher dose of pexidartinib. This process was repeated with increasingly
higher doses, as shown in the study design figure, until the highest safe dose was identified.
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For all groups, pexidartinib was given by mouth as 2 divided doses, one in the morning and one in the evening
each day. For example, the 600 mg daily group received 300 mg in the morning and 300 mg in the evening.
Paclitaxel was given as an injection in a vein once a week. The researchers identified 1600 mg daily as thehighest dose of pexidartinib that could safely be given to participants.
Participants continued to receive treatment as long as they did not show a worsening of cancer, have serious
side effects, or asked to be removed from the study.

Part 2In Part 2, 1600 mg of pexidartinib daily was given to all participants in addition to 80 mg/m² of paclitaxel oncea week. Participants continued to receive treatment as long as they did not show a worsening of cancer, haveserious side effects, or asked to be removed from the study.

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Part 3Part 3 included participants with epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer
who were receiving other treatment for cancer but either did not respond to treatment or whose cancer hadcome back after treatment. Participants were assigned to 1 of 3 treatment groups, as shown in the figure
below, which could last from 28 to 35 days.

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Changes to the study plan
Researchers found that the initial results of Part 3 for participants given pexidartinib in addition to paclitaxel
were not as beneficial as the effect of giving participants paclitaxel alone. After careful consideration, it wasdecided that no additional participants should be enrolled in Part 3 after 02 March 2017. At that time, only
18 participants were in Part 3, and they were allowed to continue in the study.

What were the key results of this study?
Key results from this study are shown for the total group of participants as average results. This summary does
not show the results from each individual participant. An individual participant’s results could be different
from the total group of participants. A full list of the questions the researchers wanted to answer and adetailed presentation of the results can be found on the website listed at the end of this summary.

Parts 1 and 2
How many participants had side effects during this study?
Side effects are medical problems (such as a feeling tired) that happened during the study which the study
doctor thought could be related to the treatments in the study.
In this study, side effects were monitored for 54 participants in Parts 1 and 2. Out of 54 participants,
51 participants (94%) reported side effects related to pexidartinib.
More detailed information about the side effects reported by participants is given below in the “MedicalProblems” section of this summary.

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Part 3How many participants had tumors that completely disappeared or became atleast 30% smaller after treatment?
The 14 participants in Part 3 were divided into 3 treatment groups, as shown below. Overall, 3 out of 14 (21%)
of participants had tumors that completely disappeared or became at least 30% smaller after treatment.

What were the other results of this study?
Parts 1 and 2
How many participants had tumors that completely disappeared or became atleast 30% smaller after treatment?
Overall, 6 out of 44 (16%) participants had tumors that completely disappeared or became at least
30% smaller after treatment. 1 participant (3%) had complete disappearance of tumors and5 participants (13%) had at least 30% reduction in tumor size.

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For participants whose tumors completely disappeared or became at least 30%smaller, how long did the effect of treatment last?
The participants who responded to treatment maintained the response for an average of about 14 weeks.
Part 3For participants whose tumors completely disappeared or became at least 30%
smaller, how long did the effect of treatment last?
The participants who responded to treatment maintained the response for an average of about 17 weeks.
How long did participants live with their cancer before it got worse or led todeath?
About half the participants lived for at least 8 weeks before their cancer got worse or led to death,
whichever occurred first.

What medical problems did the study participants have?
This section provides a summary of side effects related to the study treatment. The website listed at the endof this summary has more information about the medical problems that happened in this study.
Side effects are considered serious if they cause death, are life-threatening, cause lasting problems, or require
hospitalization. Some participants stop study treatment because of side effects.

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How many participants had serious side effects?
In this study, side effects were monitored for all 54 participants in Parts 1 and 2 and for all 18 participants inPart 3. There were no deaths reported in this study that were considered to be related to the study treatment.
Serious side effects related to pexidartinib are presented below.

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What were the most common side effects?
The most common side effects, both serious and non-serious, reported by at least 15% (15 out of 100) ofparticipants, are presented below.

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How was this study useful for patients and researchers?
This study helped researchers learn about the effects of pexidartinib in people with advanced solid tumors
when given in addition to paclitaxel. Findings from this study may be used in other studies of pexidartinib.
Other studies of pexidartinib are ongoing.
Please remember, this summary only shows the results of a single study. Other studies may have different
findings. Please talk to a doctor before changing any treatment you are taking or if you have any questions
about these study results.

Where can I learn more about this study?
You can find more information about this study on the following website:www.clinicaltrials.gov: Use the NCT identifier NCT01525602 in the search field.
Please remember that the results on this website may be presented in a different way. If you were a study
participant and have questions about the results of this study, please speak with the doctor or staff at yourstudy site.
Full study title: A Phase 1b Study to Assessthe Safety of PLX3397 and Paclitaxel in
Patients with Advanced Solid Tumors.

Sponsor: Daiichi Sankyo, Inc.
Sponsor contact information:
211 Mount Airy Road, Basking Ridge, NJ 07920
Email: CTRInfo@dsi.com
Phone number: 1-908-992-6640
Date of this summary: 27 January 2021

This summary was prepared by Kinapse, a Syneos Health® company.

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