Alkermes plc ALKS announced that it has expanded an ongoing phase I study evaluating its immuno-oncology candidate, ALKS 4230. The company a study arm to evaluate ALKS 4230 in combination with FDA-approved PD-1 inhibitor, Merck’s MRK Keytruda (pembrolizumab) in patients with advanced solid tumors. The study arm will evaluate the safety and anti-tumor activity of ALKS 4230 when administered in combination with Keytruda.The candidate works by activating and increasing immunostimulatory tumor-killing immune cells and avoids expansion of immunosuppressive cells, which interfere with anti-tumor response. Keytruda works by increasing the ability of the body's immune system in detecting and fighting tumor cells. The company expects the combination to bring synergies which will lead to improved clinical benefits.The study arm will evaluate the combination in certain PD-1 approved tumor types in both refractory and treatment naive patients, including non-small cell lung cancer, head and neck squamous cell carcinoma, gastric cancer, urothelial carcinoma, microsatellite instability-high cancers and certain PD-1 unapproved tumor types.Alkermes’s shares have decreased 26.7% so far this year compared with the industry’s fall of 4.5%.The company has several marketed products and pipeline candidates under development for the treatment of major central nervous system ("CNS") disorders including schizophrenia, depression, addiction and multiple sclerosis.The company’s top line was driven by its proprietary products, Vivitrol and Aristada, in the first half of 2018. In July, the FDA approved an extended release version of Aristada, which has achieved faster improvement in schizophrenia patients compared to Aristada.Apart from Aristada, the company is developing ALKS 3831 in phase III study for treating schizophrenia. Top-line data from the study is expected in the fourth quarter of 2018. Meanwhile, Alkermes is developing a treatment for relapsing forms of multiple sclerosis in collaboration with Biogen BIIB.With the development of ALKS 4230, the company has diversified in the oncology segment. Successful development of these treatments is likely to boost the company’s prospects.Alkermes plc Price Alkermes plc Price | Alkermes plc QuoteZacks Rank & Stock to ConsiderAlkermes currently carries a Zacks Rank #3 (Hold). Ligand Pharmaceuticals Incorporated LGND is a better-ranked stock from the pharma space, sporting a Zacks Rank #1 (Strong Buy). You can see the complete list of today’s Zacks #1 Rank stocks here.Ligand’s earnings per share estimates increased from $5.64 to $6.33 for 2018 and from $5.59 to $5.74 for 2019 in the last 30 days. The company delivered a positive earnings surprise in all the trailing four quarters, with an average beat of 59.54%. The company’s shares have rallied 85.9% year to date.5 Medical Stocks to Buy NowZacks names 5 companies poised to ride a medical breakthrough that is targeting cures for leukemia, AIDS, muscular dystrophy, hemophilia, and other conditions.New products in this field are already generating substantial revenue and even more wondrous treatments are in the pipeline. Early investors could realize exceptional profits.Click here to see the 5 stocks >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Merck & Co., Inc. (MRK): Free Stock Analysis Report Alkermes plc (ALKS): Free Stock Analysis Report Ligand Pharmaceuticals Incorporated (LGND): Free Stock Analysis Report Biogen Inc. (BIIB): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research