Gilead Sciences Inc. knew the $1,000-a-pill launch price for its hepatitis treatment would be out of reach for many patients and cause “extraordinary problems” for government health programs, according to a U.S. Senate report released Tuesday.

The 144-page committee report adds to a chorus of criticism of escalating drug prices from patients, doctors, insurers and some presidential candidates. U.S. congressional committees also have opened inquiries into drug-pricing practices by other companies including Valeant Pharmaceuticals...