Crystal forms of immunomodulators

A method of therapeutically treating cancer in a subject in need thereof comprising administering to the subject an anhydrous crystalline compound having the structure of formula (I),

• wherein:
• the crystalline compound has 2θ values of 10.2±0.2, 15.2±0.2, 15.8±0.2, 16.5±0.2, 17.6±0.2, 18.1±0.2, 18.8±0.2, 20.5±0.2, 21.8±0.2, 22.3±0.2, 22.9±0.2, 24.2±0.2, 25.4±0.2, 26.1±0.2, 26.4±0.2, 27.5±0.2, 28.1±0.2, 28.8±0.2, 29.3±0.2, 30.4±0.2, 30.6±0.2, 32.0±0.2, 33.4±0.2, 33.6±0.2, 34.6±0.2, 35.8±0.2, 36.7±0.2, 37.3±0.2, 38.2±0.2, 38.6±0.2, and 39.2±0.2;
• and
• the cancer is selected from mesothelioma, non-small cell lung cancer (NSCLC), small-cell lung cancer, lung adenocarcinoma, lung squamous cell carcinoma, lung cancer, head and neck squamous cell carcinoma (HNSCC), cancer of the head or neck, Hodgkin's lymphoma, breast cancer, colon cancer, colorectal cancer, ovarian cancer, ovarian carcinoma, triple-negative breast cancer, primary ductal carcinoma, gastric cancer, glioblastoma, renal cancer, kidney cancer, multiple myeloma, leukemia, and lymphoma.