This is a clinical trial for adults who have been diagnosed with solid tumor cancer and whose cancer is currently unresponsive to approved treatments or for whom FDA-approved treatments are worsening symptoms, as well as people who have declined to receive approved treatments.
   
This research study involves two experimental drugs called JTX-8064 (also known as the “study drug”) and JTX-4014. JTX-8064 and JTX-4014 are investigational drugs. The term “investigational” refers to any drug or device that is being tested and is not approved for sale by regulatory agencies in the country the disease or diseases are being studied. 
   
This is a first-in-human (FIH) study for JTX-8064 meaning it has not been previously tested in humans.

Depending on the part of the study, some participants may only receive the study drug (JTX-8064) whereas other subjects may receive the study drug in combination with JTX-4014, pembrolizumab, or cemiplimab. The brand name for pembrolizumab is KEYTRUDA® and the brand name for cemiplimab is LIBTAYO®. Keytruda and Libtayo have been approved by the United States Food and Drug Administration (FDA) for several different cancer indications, however they have not been approved for use in combination with JTX-8064. JTX-8064 administered alone or in combination with JTX-4014, Keytruda or Libtayo is considered experimental.
   
For this study, participants will be given JTX-8064 alone or in combination with JTX-4014, Keytruda, or Libtayo directly through a vein every 3 weeks. This is called an intravenous (IV) infusion. This infusion is done by having a needle or catheter inserted into a vein, usually in the arm. In some cases, the infusion is done through a tube or port that is connected to a vein in the chest by a surgeon. The infusion should last about 60 minutes for JTX-8064, 60 minutes for JTX-4014, and 30 minutes for Keytruda and Libtayo. For participants who are receiving two drugs, the drugs will be given one after the other with a break in between.
   
The total length of participation in the study is anticipated to be 18 to 24 months.