Merck & Co. Inc. (MRK Quick QuoteMRK - Free Report) attended the annual meeting of the American Society of Clinical Oncology (ASCO), where the company presented data on anti-PD-1 therapy, Keytruda (pembrolizumab).

As a Treatment of Cancer Deficient in DNA Mismatch Repair

Merck presented updated findings from a phase II study on Keytruda for the treatment of patients with advanced cancers characterized as deficient for DNA mismatch repair (MMR). The study evaluated the clinical activity of the drug (10 mg/kg every two weeks) in patients with previously treated, progressive metastatic disease with or without MMR-deficiency.

Results from the study revealed overall response rates (ORR) of 53% and 57% in patients with MMR-deficient advanced non-colorectal cancers, and MMR-deficient advanced colorectal cancer, respectively. However, patients with MMR-proficient advanced colorectal cancer did not respond to the therapy. The safety profile of the drug was consistent with that observed in previous studies.

Meanwhile, Keytruda is being evaluated in two phase II studies – KEYNOTE-164 and KEYNOTE-158 – in patients with previously treated, locally advanced unresectable or metastatic (Stage IV) MMR-deficient or microsatellite instability-high (MSI-H) colorectal cancer; and in patients with advanced tumors classified as MSI-H, excluding colorectal carcinoma. Moreover, Merck is evaluating Keytruda in a phase III study (KEYNOTE-177) in a treatment-naïve patient population.

As a Treatment of Advanced Melanoma

Merck also presented data from three separate studies on Keytruda – MASTERKEY-265, KEYNOTE-022, and KEYNOTE-029.

The MASTERKEY-265 (phase 1b) study evaluated the safety, efficacy and tolerability of Keytruda, in combination with Imlygic (talimogene laherparepvec), in patients with previously untreated, unresectable advanced melanoma. The KEYNOTE-022 study (phase I/II) evaluated Keytruda, in combination with Tafinlar (dabrafenib) plus Mekinist (trametinib), in patients with advanced melanoma, while the KEYNOTE-029 (phase I/II) study evaluated the drug, in combination with low-dose Yervoy (ipilimumab), in patients with advanced melanoma.

Data from the MASTERKEY-265 study showed that the combination resulted in a confirmed ORR of 57.1%, while the KEYNOTE-029 study demonstrated an ORR of 57%.

As a Treatment of Non-Small Cell Lung Cancer

Merck announced findings from a phase I/II study (KEYNOTE-021) on Keytruda, in combination with Paraplatin (carboplatin) and paclitaxel, with or without Avastin (bevacizumab), in previously untreated patients with non-small cell lung cancer (NSCLC). Results from the study revealed an ORR of 48–71%, depending on the therapy used.

Meanwhile, Merck has initiated two phase III studies in patients with previously untreated NSCLC – KEYNOTE-189 and KEYNOTE-407. KEYNOTE-189 will evaluate Keytruda, in combination with a platinum/Alimta (pemetrexed)-based chemotherapy regimen, in patients with non-squamous NSCLC, while the KEYNOTE-407 study will evaluate the drug, in combination with Paraplatin and paclitaxel or nab-paclitaxel, in patients suffering from squamous NSCLC.

We note that Keytruda is currently approved in the U.S. for the treatment of patients with unresectable or metastatic melanoma, and for the treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors express PD-L1 as determined by an FDA-approved test with disease progression on or after platinum-containing chemotherapy.

The company generated Keytruda sales of $249 million in the first-quarter of 2016, up 200% year over year.

Merck currently carries a Zacks Rank #3 (Hold). Some better-ranked stocks in the health care sector include Bristol-Myers Squibb Co. (BMY Quick QuoteBMY - Free Report) , ANI Pharmaceuticals, Inc. (ANIP Quick QuoteANIP - Free Report) and Pfizer Inc. (PFE Quick QuotePFE - Free Report) , each sporting a Zacks Rank #1 (Strong Buy).

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