Japan's Ministry of Health, Labour and Welfare (MHLW) has become the first regulator in the world to OK the use of Otsuka's Samsca (tolvaptan), making it the first approved treatment for the rare disorder autosomal dominant polycystic kidney disease (ADPKD).

ADPKD is a genetic disease in which the kidneys become enlarged due to proliferation of fluid-filled cysts. With disease progression, renal function drops leading to complications such as hypertension, haematuria and abdominal pain, and by the age of 70 half of patents reach end-stage renal failure.

In Phase-III trials, Samsca was shown to reduce the rate of change in total kidney volume - a measure of disease progression in early-stage patients - by around 50% when compared to placebo, the firm said.

Eiji Higashihara, professor of nephrology at Kyorin University School of Medicine, noted that since there has been no drug treatment for ADPKD to date, the approval is "great news" for the 30,000 or so patients diagnosed in Japan.

An application for the drug's approval in Europe is currently under review, while in the US discussions with regulators are ongoing regarding resubmission of the drug following a rejection last year on lacking safety and efficacy data.

Elsewhere, the regulator also approved: 

United Therapeutics' Remodulin (treprostinil) Injection to treat pulmonary arterial hypertension (PAH) by subcutaneous and intravenous administration, to be sold in Japan under the brand name Treprost by Mochida Pharmaceutical Co;

AstraZeneca's Forxiga (dapagliflozin in 5mg and 10mg tablets) as a once-daily oral treatment for type 2 diabetes;

Takeda's fixed-dose combination antihypertensive pill Zacras (azilsartan and amlodipine), an angiotensin II receptor blocker, and the firm's peptic ulcer treatment Takelda (100mg aspirin with 15mg lansoprazole), the first FDC drug in Japan to combine low-dose aspirin with a proton pump inhibitor; and

Astellas and Medivation's oral androgen receptor inhibitor Xtandi (enzalutamide) for the treatment of patients with castration-resistant prostate cancer (CRPC).