A Rollover Study Evaluating Sotorasib With or Without Panitumumab in Participants With KRAS p.G12C Mutation

Inclusion Criteria: * Signed informed consent. * Age ≥ 18 years. * Life expectancy of \> 3 months, in the opinion of the investigator. * Ability to take oral medications and willing to record daily adherence to sotorasib through the use of a written diary. * Participant is currently receiving treatment with sotorasib alone or in combination therapy in an Amgen-sponsored trial that has met its endpoints or otherwise will be stopping (also referred to as parent study) and are continuing to receive clinical benefit in the opinion of the investigator. * For a participant on combination therapy in their parent study, treatment with other anti-cancer therapies is allowed provided it matches the parent study. * Eastern Cooperative Oncology Group Performance Status of ≤ 2. Exclusion Criteria: * Participant had permanently discontinued from sotorasib study treatment in the parent study before the parent study's completion. * Ongoing, unresolved toxicity requiring interruption of sotorasib treatment at the time of the termination of the parent study. * Local access to commercially available investigational product(s) at no cost to the participant as permitted by local/country regulation. * Anticipated toxicities of sotorasib study treatment outweigh the clinical benefit to the participant in the opinion of the investigator. * Participant unlikely to be able to complete all protocol-required procedures, restrictions and requirements, in the judgment of the individual and investigator. * Significant uncontrolled concomitant disease that could affect compliance with protocol procedures or interpretation of results or that pose a risk to participant safety, in the opinion of the investigator. * Female participants of childbearing potential unwilling to use protocol-specified method of contraception during treatment and for an additional: * 7 days after the last dose of sotorasib. * 2 months after the last dose of panitumumab. * Female participants who are breastfeeding or who plan to breastfeed while on study through: * 7 days after the last dose of sotorasib. * 2 months after the last dose of panitumumab. * Female participants planning to become pregnant while on study through: * 7 days after the last dose of sotorasib. * 2 months after the last dose of panitumumab. * Female participants of childbearing potential with a positive pregnancy test assessed at screening or day 1 by a highly sensitive urine or serum pregnancy test. * Male participants with a female partner of childbearing potential who are unwilling to practice sexual abstinence (refrain from heterosexual intercourse) or use contraception during treatment and for an additional 7 days after the last dose of sotorasib. * Male participants with a pregnant partner who are unwilling to practice abstinence or use a condom during treatment and for an additional 7 days after the last dose of sotorasib. * Male participants unwilling to abstain from donating sperm during treatment and for an additional 7 days after the last dose of sotorasib.